1 /*- 2 * Copyright (c) 1990 University of Utah. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * Copyright (c) 1993, 1994 John S. Dyson 6 * Copyright (c) 1995, David Greenman 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 41 */ 42 43 /* 44 * Page to/from files (vnodes). 45 */ 46 47 /* 48 * TODO: 49 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 50 * greatly re-simplify the vnode_pager. 51 */ 52 53 #include <sys/cdefs.h> 54 __FBSDID("$FreeBSD$"); 55 56 #include "opt_vm.h" 57 58 #include <sys/param.h> 59 #include <sys/systm.h> 60 #include <sys/proc.h> 61 #include <sys/vnode.h> 62 #include <sys/mount.h> 63 #include <sys/bio.h> 64 #include <sys/buf.h> 65 #include <sys/vmmeter.h> 66 #include <sys/limits.h> 67 #include <sys/conf.h> 68 #include <sys/rwlock.h> 69 #include <sys/sf_buf.h> 70 71 #include <machine/atomic.h> 72 73 #include <vm/vm.h> 74 #include <vm/vm_param.h> 75 #include <vm/vm_object.h> 76 #include <vm/vm_page.h> 77 #include <vm/vm_pager.h> 78 #include <vm/vm_map.h> 79 #include <vm/vnode_pager.h> 80 #include <vm/vm_extern.h> 81 82 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 83 daddr_t *rtaddress, int *run); 84 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 85 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 86 static void vnode_pager_dealloc(vm_object_t); 87 static int vnode_pager_local_getpages0(struct vnode *, vm_page_t *, int, int, 88 vop_getpages_iodone_t, void *); 89 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 90 static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int, 91 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 if (obj->ref_count == 0) { 170 /* 171 * don't double-terminate the object 172 */ 173 if ((obj->flags & OBJ_DEAD) == 0) 174 vm_object_terminate(obj); 175 else 176 VM_OBJECT_WUNLOCK(obj); 177 } else { 178 /* 179 * Woe to the process that tries to page now :-). 180 */ 181 vm_pager_deallocate(obj); 182 VM_OBJECT_WUNLOCK(obj); 183 } 184 vp->v_object = NULL; 185 } 186 187 188 /* 189 * Allocate (or lookup) pager for a vnode. 190 * Handle is a vnode pointer. 191 * 192 * MPSAFE 193 */ 194 vm_object_t 195 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 196 vm_ooffset_t offset, struct ucred *cred) 197 { 198 vm_object_t object; 199 struct vnode *vp; 200 201 /* 202 * Pageout to vnode, no can do yet. 203 */ 204 if (handle == NULL) 205 return (NULL); 206 207 vp = (struct vnode *) handle; 208 209 /* 210 * If the object is being terminated, wait for it to 211 * go away. 212 */ 213 retry: 214 while ((object = vp->v_object) != NULL) { 215 VM_OBJECT_WLOCK(object); 216 if ((object->flags & OBJ_DEAD) == 0) 217 break; 218 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 219 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0); 220 } 221 222 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference")); 223 224 if (object == NULL) { 225 /* 226 * Add an object of the appropriate size 227 */ 228 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 229 230 object->un_pager.vnp.vnp_size = size; 231 object->un_pager.vnp.writemappings = 0; 232 233 object->handle = handle; 234 VI_LOCK(vp); 235 if (vp->v_object != NULL) { 236 /* 237 * Object has been created while we were sleeping 238 */ 239 VI_UNLOCK(vp); 240 vm_object_destroy(object); 241 goto retry; 242 } 243 vp->v_object = object; 244 VI_UNLOCK(vp); 245 } else { 246 object->ref_count++; 247 #if VM_NRESERVLEVEL > 0 248 vm_object_color(object, 0); 249 #endif 250 VM_OBJECT_WUNLOCK(object); 251 } 252 vref(vp); 253 return (object); 254 } 255 256 /* 257 * The object must be locked. 258 */ 259 static void 260 vnode_pager_dealloc(vm_object_t object) 261 { 262 struct vnode *vp; 263 int refs; 264 265 vp = object->handle; 266 if (vp == NULL) 267 panic("vnode_pager_dealloc: pager already dealloced"); 268 269 VM_OBJECT_ASSERT_WLOCKED(object); 270 vm_object_pip_wait(object, "vnpdea"); 271 refs = object->ref_count; 272 273 object->handle = NULL; 274 object->type = OBJT_DEAD; 275 if (object->flags & OBJ_DISCONNECTWNT) { 276 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 277 wakeup(object); 278 } 279 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 280 if (object->un_pager.vnp.writemappings > 0) { 281 object->un_pager.vnp.writemappings = 0; 282 VOP_ADD_WRITECOUNT(vp, -1); 283 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 284 __func__, vp, vp->v_writecount); 285 } 286 vp->v_object = NULL; 287 VOP_UNSET_TEXT(vp); 288 VM_OBJECT_WUNLOCK(object); 289 while (refs-- > 0) 290 vunref(vp); 291 VM_OBJECT_WLOCK(object); 292 } 293 294 static boolean_t 295 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 296 int *after) 297 { 298 struct vnode *vp = object->handle; 299 daddr_t bn; 300 int err; 301 daddr_t reqblock; 302 int poff; 303 int bsize; 304 int pagesperblock, blocksperpage; 305 306 VM_OBJECT_ASSERT_WLOCKED(object); 307 /* 308 * If no vp or vp is doomed or marked transparent to VM, we do not 309 * have the page. 310 */ 311 if (vp == NULL || vp->v_iflag & VI_DOOMED) 312 return FALSE; 313 /* 314 * If the offset is beyond end of file we do 315 * not have the page. 316 */ 317 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 318 return FALSE; 319 320 bsize = vp->v_mount->mnt_stat.f_iosize; 321 pagesperblock = bsize / PAGE_SIZE; 322 blocksperpage = 0; 323 if (pagesperblock > 0) { 324 reqblock = pindex / pagesperblock; 325 } else { 326 blocksperpage = (PAGE_SIZE / bsize); 327 reqblock = pindex * blocksperpage; 328 } 329 VM_OBJECT_WUNLOCK(object); 330 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 331 VM_OBJECT_WLOCK(object); 332 if (err) 333 return TRUE; 334 if (bn == -1) 335 return FALSE; 336 if (pagesperblock > 0) { 337 poff = pindex - (reqblock * pagesperblock); 338 if (before) { 339 *before *= pagesperblock; 340 *before += poff; 341 } 342 if (after) { 343 /* 344 * The BMAP vop can report a partial block in the 345 * 'after', but must not report blocks after EOF. 346 * Assert the latter, and truncate 'after' in case 347 * of the former. 348 */ 349 KASSERT((reqblock + *after) * pagesperblock < 350 roundup2(object->size, pagesperblock), 351 ("%s: reqblock %jd after %d size %ju", __func__, 352 (intmax_t )reqblock, *after, 353 (uintmax_t )object->size)); 354 *after *= pagesperblock; 355 *after += pagesperblock - (poff + 1); 356 if (pindex + *after >= object->size) 357 *after = object->size - 1 - pindex; 358 } 359 } else { 360 if (before) { 361 *before /= blocksperpage; 362 } 363 364 if (after) { 365 *after /= blocksperpage; 366 } 367 } 368 return TRUE; 369 } 370 371 /* 372 * Lets the VM system know about a change in size for a file. 373 * We adjust our own internal size and flush any cached pages in 374 * the associated object that are affected by the size change. 375 * 376 * Note: this routine may be invoked as a result of a pager put 377 * operation (possibly at object termination time), so we must be careful. 378 */ 379 void 380 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 381 { 382 vm_object_t object; 383 vm_page_t m; 384 vm_pindex_t nobjsize; 385 386 if ((object = vp->v_object) == NULL) 387 return; 388 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 389 VM_OBJECT_WLOCK(object); 390 if (object->type == OBJT_DEAD) { 391 VM_OBJECT_WUNLOCK(object); 392 return; 393 } 394 KASSERT(object->type == OBJT_VNODE, 395 ("not vnode-backed object %p", object)); 396 if (nsize == object->un_pager.vnp.vnp_size) { 397 /* 398 * Hasn't changed size 399 */ 400 VM_OBJECT_WUNLOCK(object); 401 return; 402 } 403 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 404 if (nsize < object->un_pager.vnp.vnp_size) { 405 /* 406 * File has shrunk. Toss any cached pages beyond the new EOF. 407 */ 408 if (nobjsize < object->size) 409 vm_object_page_remove(object, nobjsize, object->size, 410 0); 411 /* 412 * this gets rid of garbage at the end of a page that is now 413 * only partially backed by the vnode. 414 * 415 * XXX for some reason (I don't know yet), if we take a 416 * completely invalid page and mark it partially valid 417 * it can screw up NFS reads, so we don't allow the case. 418 */ 419 if ((nsize & PAGE_MASK) && 420 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 421 m->valid != 0) { 422 int base = (int)nsize & PAGE_MASK; 423 int size = PAGE_SIZE - base; 424 425 /* 426 * Clear out partial-page garbage in case 427 * the page has been mapped. 428 */ 429 pmap_zero_page_area(m, base, size); 430 431 /* 432 * Update the valid bits to reflect the blocks that 433 * have been zeroed. Some of these valid bits may 434 * have already been set. 435 */ 436 vm_page_set_valid_range(m, base, size); 437 438 /* 439 * Round "base" to the next block boundary so that the 440 * dirty bit for a partially zeroed block is not 441 * cleared. 442 */ 443 base = roundup2(base, DEV_BSIZE); 444 445 /* 446 * Clear out partial-page dirty bits. 447 * 448 * note that we do not clear out the valid 449 * bits. This would prevent bogus_page 450 * replacement from working properly. 451 */ 452 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 453 } else if ((nsize & PAGE_MASK) && 454 vm_page_is_cached(object, OFF_TO_IDX(nsize))) { 455 vm_page_cache_free(object, OFF_TO_IDX(nsize), 456 nobjsize); 457 } 458 } 459 object->un_pager.vnp.vnp_size = nsize; 460 object->size = nobjsize; 461 VM_OBJECT_WUNLOCK(object); 462 } 463 464 /* 465 * calculate the linear (byte) disk address of specified virtual 466 * file address 467 */ 468 static int 469 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 470 int *run) 471 { 472 int bsize; 473 int err; 474 daddr_t vblock; 475 daddr_t voffset; 476 477 if (address < 0) 478 return -1; 479 480 if (vp->v_iflag & VI_DOOMED) 481 return -1; 482 483 bsize = vp->v_mount->mnt_stat.f_iosize; 484 vblock = address / bsize; 485 voffset = address % bsize; 486 487 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 488 if (err == 0) { 489 if (*rtaddress != -1) 490 *rtaddress += voffset / DEV_BSIZE; 491 if (run) { 492 *run += 1; 493 *run *= bsize/PAGE_SIZE; 494 *run -= voffset/PAGE_SIZE; 495 } 496 } 497 498 return (err); 499 } 500 501 /* 502 * small block filesystem vnode pager input 503 */ 504 static int 505 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m) 506 { 507 struct vnode *vp; 508 struct bufobj *bo; 509 struct buf *bp; 510 struct sf_buf *sf; 511 daddr_t fileaddr; 512 vm_offset_t bsize; 513 vm_page_bits_t bits; 514 int error, i; 515 516 error = 0; 517 vp = object->handle; 518 if (vp->v_iflag & VI_DOOMED) 519 return VM_PAGER_BAD; 520 521 bsize = vp->v_mount->mnt_stat.f_iosize; 522 523 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 524 525 sf = sf_buf_alloc(m, 0); 526 527 for (i = 0; i < PAGE_SIZE / bsize; i++) { 528 vm_ooffset_t address; 529 530 bits = vm_page_bits(i * bsize, bsize); 531 if (m->valid & bits) 532 continue; 533 534 address = IDX_TO_OFF(m->pindex) + i * bsize; 535 if (address >= object->un_pager.vnp.vnp_size) { 536 fileaddr = -1; 537 } else { 538 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 539 if (error) 540 break; 541 } 542 if (fileaddr != -1) { 543 bp = getpbuf(&vnode_pbuf_freecnt); 544 545 /* build a minimal buffer header */ 546 bp->b_iocmd = BIO_READ; 547 bp->b_iodone = bdone; 548 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 549 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 550 bp->b_rcred = crhold(curthread->td_ucred); 551 bp->b_wcred = crhold(curthread->td_ucred); 552 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 553 bp->b_blkno = fileaddr; 554 pbgetbo(bo, bp); 555 bp->b_vp = vp; 556 bp->b_bcount = bsize; 557 bp->b_bufsize = bsize; 558 bp->b_runningbufspace = bp->b_bufsize; 559 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 560 561 /* do the input */ 562 bp->b_iooffset = dbtob(bp->b_blkno); 563 bstrategy(bp); 564 565 bwait(bp, PVM, "vnsrd"); 566 567 if ((bp->b_ioflags & BIO_ERROR) != 0) 568 error = EIO; 569 570 /* 571 * free the buffer header back to the swap buffer pool 572 */ 573 bp->b_vp = NULL; 574 pbrelbo(bp); 575 relpbuf(bp, &vnode_pbuf_freecnt); 576 if (error) 577 break; 578 } else 579 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 580 KASSERT((m->dirty & bits) == 0, 581 ("vnode_pager_input_smlfs: page %p is dirty", m)); 582 VM_OBJECT_WLOCK(object); 583 m->valid |= bits; 584 VM_OBJECT_WUNLOCK(object); 585 } 586 sf_buf_free(sf); 587 if (error) { 588 return VM_PAGER_ERROR; 589 } 590 return VM_PAGER_OK; 591 } 592 593 /* 594 * old style vnode pager input routine 595 */ 596 static int 597 vnode_pager_input_old(vm_object_t object, vm_page_t m) 598 { 599 struct uio auio; 600 struct iovec aiov; 601 int error; 602 int size; 603 struct sf_buf *sf; 604 struct vnode *vp; 605 606 VM_OBJECT_ASSERT_WLOCKED(object); 607 error = 0; 608 609 /* 610 * Return failure if beyond current EOF 611 */ 612 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 613 return VM_PAGER_BAD; 614 } else { 615 size = PAGE_SIZE; 616 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 617 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 618 vp = object->handle; 619 VM_OBJECT_WUNLOCK(object); 620 621 /* 622 * Allocate a kernel virtual address and initialize so that 623 * we can use VOP_READ/WRITE routines. 624 */ 625 sf = sf_buf_alloc(m, 0); 626 627 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 628 aiov.iov_len = size; 629 auio.uio_iov = &aiov; 630 auio.uio_iovcnt = 1; 631 auio.uio_offset = IDX_TO_OFF(m->pindex); 632 auio.uio_segflg = UIO_SYSSPACE; 633 auio.uio_rw = UIO_READ; 634 auio.uio_resid = size; 635 auio.uio_td = curthread; 636 637 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 638 if (!error) { 639 int count = size - auio.uio_resid; 640 641 if (count == 0) 642 error = EINVAL; 643 else if (count != PAGE_SIZE) 644 bzero((caddr_t)sf_buf_kva(sf) + count, 645 PAGE_SIZE - count); 646 } 647 sf_buf_free(sf); 648 649 VM_OBJECT_WLOCK(object); 650 } 651 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 652 if (!error) 653 m->valid = VM_PAGE_BITS_ALL; 654 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 655 } 656 657 /* 658 * generic vnode pager input routine 659 */ 660 661 /* 662 * Local media VFS's that do not implement their own VOP_GETPAGES 663 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 664 * to implement the previous behaviour. 665 * 666 * All other FS's should use the bypass to get to the local media 667 * backing vp's VOP_GETPAGES. 668 */ 669 static int 670 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 671 { 672 int rtval; 673 struct vnode *vp; 674 int bytes = count * PAGE_SIZE; 675 676 vp = object->handle; 677 VM_OBJECT_WUNLOCK(object); 678 rtval = VOP_GETPAGES(vp, m, bytes, reqpage); 679 KASSERT(rtval != EOPNOTSUPP, 680 ("vnode_pager: FS getpages not implemented\n")); 681 VM_OBJECT_WLOCK(object); 682 return rtval; 683 } 684 685 static int 686 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count, 687 int reqpage, vop_getpages_iodone_t iodone, void *arg) 688 { 689 struct vnode *vp; 690 int rtval; 691 692 vp = object->handle; 693 VM_OBJECT_WUNLOCK(object); 694 rtval = VOP_GETPAGES_ASYNC(vp, m, count * PAGE_SIZE, reqpage, 695 iodone, arg); 696 KASSERT(rtval != EOPNOTSUPP, 697 ("vnode_pager: FS getpages_async not implemented\n")); 698 VM_OBJECT_WLOCK(object); 699 return (rtval); 700 } 701 702 /* 703 * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for 704 * local filesystems, where partially valid pages can only occur at 705 * the end of file. 706 */ 707 int 708 vnode_pager_local_getpages(struct vop_getpages_args *ap) 709 { 710 711 return (vnode_pager_local_getpages0(ap->a_vp, ap->a_m, ap->a_count, 712 ap->a_reqpage, NULL, NULL)); 713 } 714 715 int 716 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap) 717 { 718 719 return (vnode_pager_local_getpages0(ap->a_vp, ap->a_m, ap->a_count, 720 ap->a_reqpage, ap->a_iodone, ap->a_arg)); 721 } 722 723 static int 724 vnode_pager_local_getpages0(struct vnode *vp, vm_page_t *m, int bytecount, 725 int reqpage, vop_getpages_iodone_t iodone, void *arg) 726 { 727 vm_page_t mreq; 728 729 mreq = m[reqpage]; 730 731 /* 732 * Since the caller has busied the requested page, that page's valid 733 * field will not be changed by other threads. 734 */ 735 vm_page_assert_xbusied(mreq); 736 737 /* 738 * The requested page has valid blocks. Invalid part can only 739 * exist at the end of file, and the page is made fully valid 740 * by zeroing in vm_pager_get_pages(). Free non-requested 741 * pages, since no i/o is done to read its content. 742 */ 743 if (mreq->valid != 0) { 744 vm_pager_free_nonreq(mreq->object, m, reqpage, 745 round_page(bytecount) / PAGE_SIZE, FALSE); 746 if (iodone != NULL) 747 iodone(arg, m, reqpage, 0); 748 return (VM_PAGER_OK); 749 } 750 751 return (vnode_pager_generic_getpages(vp, m, bytecount, reqpage, 752 iodone, arg)); 753 } 754 755 /* 756 * This is now called from local media FS's to operate against their 757 * own vnodes if they fail to implement VOP_GETPAGES. 758 */ 759 int 760 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount, 761 int reqpage, vop_getpages_iodone_t iodone, void *arg) 762 { 763 vm_object_t object; 764 off_t foff; 765 int i, j, size, bsize, first, *freecnt; 766 daddr_t firstaddr, reqblock; 767 struct bufobj *bo; 768 int runpg; 769 int runend; 770 struct buf *bp; 771 int count; 772 int error; 773 774 object = vp->v_object; 775 count = bytecount / PAGE_SIZE; 776 777 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 778 ("vnode_pager_generic_getpages does not support devices")); 779 if (vp->v_iflag & VI_DOOMED) 780 return VM_PAGER_BAD; 781 782 bsize = vp->v_mount->mnt_stat.f_iosize; 783 foff = IDX_TO_OFF(m[reqpage]->pindex); 784 785 /* 786 * Synchronous and asynchronous paging operations use different 787 * free pbuf counters. This is done to avoid asynchronous requests 788 * to consume all pbufs. 789 * Allocate the pbuf at the very beginning of the function, so that 790 * if we are low on certain kind of pbufs don't even proceed to BMAP, 791 * but sleep. 792 */ 793 freecnt = iodone != NULL ? 794 &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt; 795 bp = getpbuf(freecnt); 796 797 /* 798 * Get the underlying device blocks for the file with VOP_BMAP(). 799 * If the file system doesn't support VOP_BMAP, use old way of 800 * getting pages via VOP_READ. 801 */ 802 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL); 803 if (error == EOPNOTSUPP) { 804 relpbuf(bp, freecnt); 805 VM_OBJECT_WLOCK(object); 806 for (i = 0; i < count; i++) 807 if (i != reqpage) { 808 vm_page_lock(m[i]); 809 vm_page_free(m[i]); 810 vm_page_unlock(m[i]); 811 } 812 PCPU_INC(cnt.v_vnodein); 813 PCPU_INC(cnt.v_vnodepgsin); 814 error = vnode_pager_input_old(object, m[reqpage]); 815 VM_OBJECT_WUNLOCK(object); 816 return (error); 817 } else if (error != 0) { 818 relpbuf(bp, freecnt); 819 vm_pager_free_nonreq(object, m, reqpage, count, FALSE); 820 return (VM_PAGER_ERROR); 821 822 /* 823 * if the blocksize is smaller than a page size, then use 824 * special small filesystem code. NFS sometimes has a small 825 * blocksize, but it can handle large reads itself. 826 */ 827 } else if ((PAGE_SIZE / bsize) > 1 && 828 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 829 relpbuf(bp, freecnt); 830 vm_pager_free_nonreq(object, m, reqpage, count, FALSE); 831 PCPU_INC(cnt.v_vnodein); 832 PCPU_INC(cnt.v_vnodepgsin); 833 return vnode_pager_input_smlfs(object, m[reqpage]); 834 } 835 836 /* 837 * Since the caller has busied the requested page, that page's valid 838 * field will not be changed by other threads. 839 */ 840 vm_page_assert_xbusied(m[reqpage]); 841 842 /* 843 * If we have a completely valid page available to us, we can 844 * clean up and return. Otherwise we have to re-read the 845 * media. 846 */ 847 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 848 relpbuf(bp, freecnt); 849 vm_pager_free_nonreq(object, m, reqpage, count, FALSE); 850 return (VM_PAGER_OK); 851 } else if (reqblock == -1) { 852 relpbuf(bp, freecnt); 853 pmap_zero_page(m[reqpage]); 854 KASSERT(m[reqpage]->dirty == 0, 855 ("vnode_pager_generic_getpages: page %p is dirty", m)); 856 VM_OBJECT_WLOCK(object); 857 m[reqpage]->valid = VM_PAGE_BITS_ALL; 858 vm_pager_free_nonreq(object, m, reqpage, count, TRUE); 859 VM_OBJECT_WUNLOCK(object); 860 return (VM_PAGER_OK); 861 } else if (m[reqpage]->valid != 0) { 862 VM_OBJECT_WLOCK(object); 863 m[reqpage]->valid = 0; 864 VM_OBJECT_WUNLOCK(object); 865 } 866 867 /* 868 * here on direct device I/O 869 */ 870 firstaddr = -1; 871 872 /* 873 * calculate the run that includes the required page 874 */ 875 for (first = 0, i = 0; i < count; i = runend) { 876 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr, 877 &runpg) != 0) { 878 relpbuf(bp, freecnt); 879 /* The requested page may be out of range. */ 880 vm_pager_free_nonreq(object, m + i, reqpage - i, 881 count - i, FALSE); 882 return (VM_PAGER_ERROR); 883 } 884 if (firstaddr == -1) { 885 VM_OBJECT_WLOCK(object); 886 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 887 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 888 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 889 (uintmax_t)foff, 890 (uintmax_t) 891 (object->un_pager.vnp.vnp_size >> 32), 892 (uintmax_t)object->un_pager.vnp.vnp_size); 893 } 894 vm_page_lock(m[i]); 895 vm_page_free(m[i]); 896 vm_page_unlock(m[i]); 897 VM_OBJECT_WUNLOCK(object); 898 runend = i + 1; 899 first = runend; 900 continue; 901 } 902 runend = i + runpg; 903 if (runend <= reqpage) { 904 VM_OBJECT_WLOCK(object); 905 for (j = i; j < runend; j++) { 906 vm_page_lock(m[j]); 907 vm_page_free(m[j]); 908 vm_page_unlock(m[j]); 909 } 910 VM_OBJECT_WUNLOCK(object); 911 } else { 912 if (runpg < (count - first)) { 913 VM_OBJECT_WLOCK(object); 914 for (i = first + runpg; i < count; i++) { 915 vm_page_lock(m[i]); 916 vm_page_free(m[i]); 917 vm_page_unlock(m[i]); 918 } 919 VM_OBJECT_WUNLOCK(object); 920 count = first + runpg; 921 } 922 break; 923 } 924 first = runend; 925 } 926 927 /* 928 * the first and last page have been calculated now, move input pages 929 * to be zero based... 930 */ 931 if (first != 0) { 932 m += first; 933 count -= first; 934 reqpage -= first; 935 } 936 937 /* 938 * calculate the file virtual address for the transfer 939 */ 940 foff = IDX_TO_OFF(m[0]->pindex); 941 942 /* 943 * calculate the size of the transfer 944 */ 945 size = count * PAGE_SIZE; 946 KASSERT(count > 0, ("zero count")); 947 if ((foff + size) > object->un_pager.vnp.vnp_size) 948 size = object->un_pager.vnp.vnp_size - foff; 949 KASSERT(size > 0, ("zero size")); 950 951 /* 952 * round up physical size for real devices. 953 */ 954 if (1) { 955 int secmask = bo->bo_bsize - 1; 956 KASSERT(secmask < PAGE_SIZE && secmask > 0, 957 ("vnode_pager_generic_getpages: sector size %d too large", 958 secmask + 1)); 959 size = (size + secmask) & ~secmask; 960 } 961 962 bp->b_kvaalloc = bp->b_data; 963 964 /* 965 * and map the pages to be read into the kva, if the filesystem 966 * requires mapped buffers. 967 */ 968 if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 969 unmapped_buf_allowed) { 970 bp->b_data = unmapped_buf; 971 bp->b_kvabase = unmapped_buf; 972 bp->b_offset = 0; 973 bp->b_flags |= B_UNMAPPED; 974 } else 975 pmap_qenter((vm_offset_t)bp->b_kvaalloc, m, count); 976 977 /* build a minimal buffer header */ 978 bp->b_iocmd = BIO_READ; 979 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 980 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 981 bp->b_rcred = crhold(curthread->td_ucred); 982 bp->b_wcred = crhold(curthread->td_ucred); 983 bp->b_blkno = firstaddr; 984 pbgetbo(bo, bp); 985 bp->b_vp = vp; 986 bp->b_bcount = size; 987 bp->b_bufsize = size; 988 bp->b_runningbufspace = bp->b_bufsize; 989 for (i = 0; i < count; i++) 990 bp->b_pages[i] = m[i]; 991 bp->b_npages = count; 992 bp->b_pager.pg_reqpage = reqpage; 993 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 994 995 PCPU_INC(cnt.v_vnodein); 996 PCPU_ADD(cnt.v_vnodepgsin, count); 997 998 /* do the input */ 999 bp->b_iooffset = dbtob(bp->b_blkno); 1000 1001 if (iodone != NULL) { /* async */ 1002 bp->b_pager.pg_iodone = iodone; 1003 bp->b_caller1 = arg; 1004 bp->b_iodone = vnode_pager_generic_getpages_done_async; 1005 bp->b_flags |= B_ASYNC; 1006 BUF_KERNPROC(bp); 1007 bstrategy(bp); 1008 /* Good bye! */ 1009 } else { 1010 bp->b_iodone = bdone; 1011 bstrategy(bp); 1012 bwait(bp, PVM, "vnread"); 1013 error = vnode_pager_generic_getpages_done(bp); 1014 for (i = 0; i < bp->b_npages; i++) 1015 bp->b_pages[i] = NULL; 1016 bp->b_vp = NULL; 1017 pbrelbo(bp); 1018 relpbuf(bp, &vnode_pbuf_freecnt); 1019 } 1020 1021 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 1022 } 1023 1024 static void 1025 vnode_pager_generic_getpages_done_async(struct buf *bp) 1026 { 1027 int error; 1028 1029 error = vnode_pager_generic_getpages_done(bp); 1030 bp->b_pager.pg_iodone(bp->b_caller1, bp->b_pages, 1031 bp->b_pager.pg_reqpage, error); 1032 for (int i = 0; i < bp->b_npages; i++) 1033 bp->b_pages[i] = NULL; 1034 bp->b_vp = NULL; 1035 pbrelbo(bp); 1036 relpbuf(bp, &vnode_async_pbuf_freecnt); 1037 } 1038 1039 static int 1040 vnode_pager_generic_getpages_done(struct buf *bp) 1041 { 1042 vm_object_t object; 1043 off_t tfoff, nextoff; 1044 int i, error; 1045 1046 error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0; 1047 object = bp->b_vp->v_object; 1048 1049 if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) { 1050 if ((bp->b_flags & B_UNMAPPED) != 0) { 1051 bp->b_flags &= ~B_UNMAPPED; 1052 pmap_qenter((vm_offset_t)bp->b_kvaalloc, bp->b_pages, 1053 bp->b_npages); 1054 } 1055 bzero(bp->b_kvaalloc + bp->b_bcount, 1056 PAGE_SIZE * bp->b_npages - bp->b_bcount); 1057 } 1058 if ((bp->b_flags & B_UNMAPPED) == 0) 1059 pmap_qremove((vm_offset_t)bp->b_kvaalloc, bp->b_npages); 1060 if ((bp->b_vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0) { 1061 bp->b_data = bp->b_kvaalloc; 1062 bp->b_kvabase = bp->b_kvaalloc; 1063 bp->b_flags &= ~B_UNMAPPED; 1064 } 1065 1066 VM_OBJECT_WLOCK(object); 1067 for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex); 1068 i < bp->b_npages; i++, tfoff = nextoff) { 1069 vm_page_t mt; 1070 1071 nextoff = tfoff + PAGE_SIZE; 1072 mt = bp->b_pages[i]; 1073 1074 if (nextoff <= object->un_pager.vnp.vnp_size) { 1075 /* 1076 * Read filled up entire page. 1077 */ 1078 mt->valid = VM_PAGE_BITS_ALL; 1079 KASSERT(mt->dirty == 0, 1080 ("%s: page %p is dirty", __func__, mt)); 1081 KASSERT(!pmap_page_is_mapped(mt), 1082 ("%s: page %p is mapped", __func__, mt)); 1083 } else { 1084 /* 1085 * Read did not fill up entire page. 1086 * 1087 * Currently we do not set the entire page valid, 1088 * we just try to clear the piece that we couldn't 1089 * read. 1090 */ 1091 vm_page_set_valid_range(mt, 0, 1092 object->un_pager.vnp.vnp_size - tfoff); 1093 KASSERT((mt->dirty & vm_page_bits(0, 1094 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1095 ("%s: page %p is dirty", __func__, mt)); 1096 } 1097 1098 if (i != bp->b_pager.pg_reqpage) 1099 vm_page_readahead_finish(mt); 1100 } 1101 VM_OBJECT_WUNLOCK(object); 1102 if (error != 0) 1103 printf("%s: I/O read error %d\n", __func__, error); 1104 1105 return (error); 1106 } 1107 1108 /* 1109 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1110 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1111 * vnode_pager_generic_putpages() to implement the previous behaviour. 1112 * 1113 * All other FS's should use the bypass to get to the local media 1114 * backing vp's VOP_PUTPAGES. 1115 */ 1116 static void 1117 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 1118 int flags, int *rtvals) 1119 { 1120 int rtval; 1121 struct vnode *vp; 1122 int bytes = count * PAGE_SIZE; 1123 1124 /* 1125 * Force synchronous operation if we are extremely low on memory 1126 * to prevent a low-memory deadlock. VOP operations often need to 1127 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1128 * operation ). The swapper handles the case by limiting the amount 1129 * of asynchronous I/O, but that sort of solution doesn't scale well 1130 * for the vnode pager without a lot of work. 1131 * 1132 * Also, the backing vnode's iodone routine may not wake the pageout 1133 * daemon up. This should be probably be addressed XXX. 1134 */ 1135 1136 if (vm_cnt.v_free_count + vm_cnt.v_cache_count < 1137 vm_cnt.v_pageout_free_min) 1138 flags |= VM_PAGER_PUT_SYNC; 1139 1140 /* 1141 * Call device-specific putpages function 1142 */ 1143 vp = object->handle; 1144 VM_OBJECT_WUNLOCK(object); 1145 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals); 1146 KASSERT(rtval != EOPNOTSUPP, 1147 ("vnode_pager: stale FS putpages\n")); 1148 VM_OBJECT_WLOCK(object); 1149 } 1150 1151 1152 /* 1153 * This is now called from local media FS's to operate against their 1154 * own vnodes if they fail to implement VOP_PUTPAGES. 1155 * 1156 * This is typically called indirectly via the pageout daemon and 1157 * clustering has already typically occured, so in general we ask the 1158 * underlying filesystem to write the data out asynchronously rather 1159 * then delayed. 1160 */ 1161 int 1162 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1163 int flags, int *rtvals) 1164 { 1165 int i; 1166 vm_object_t object; 1167 vm_page_t m; 1168 int count; 1169 1170 int maxsize, ncount; 1171 vm_ooffset_t poffset; 1172 struct uio auio; 1173 struct iovec aiov; 1174 int error; 1175 int ioflags; 1176 int ppscheck = 0; 1177 static struct timeval lastfail; 1178 static int curfail; 1179 1180 object = vp->v_object; 1181 count = bytecount / PAGE_SIZE; 1182 1183 for (i = 0; i < count; i++) 1184 rtvals[i] = VM_PAGER_ERROR; 1185 1186 if ((int64_t)ma[0]->pindex < 0) { 1187 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1188 (long)ma[0]->pindex, (u_long)ma[0]->dirty); 1189 rtvals[0] = VM_PAGER_BAD; 1190 return VM_PAGER_BAD; 1191 } 1192 1193 maxsize = count * PAGE_SIZE; 1194 ncount = count; 1195 1196 poffset = IDX_TO_OFF(ma[0]->pindex); 1197 1198 /* 1199 * If the page-aligned write is larger then the actual file we 1200 * have to invalidate pages occuring beyond the file EOF. However, 1201 * there is an edge case where a file may not be page-aligned where 1202 * the last page is partially invalid. In this case the filesystem 1203 * may not properly clear the dirty bits for the entire page (which 1204 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1205 * With the page locked we are free to fix-up the dirty bits here. 1206 * 1207 * We do not under any circumstances truncate the valid bits, as 1208 * this will screw up bogus page replacement. 1209 */ 1210 VM_OBJECT_WLOCK(object); 1211 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1212 if (object->un_pager.vnp.vnp_size > poffset) { 1213 int pgoff; 1214 1215 maxsize = object->un_pager.vnp.vnp_size - poffset; 1216 ncount = btoc(maxsize); 1217 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1218 /* 1219 * If the object is locked and the following 1220 * conditions hold, then the page's dirty 1221 * field cannot be concurrently changed by a 1222 * pmap operation. 1223 */ 1224 m = ma[ncount - 1]; 1225 vm_page_assert_sbusied(m); 1226 KASSERT(!pmap_page_is_write_mapped(m), 1227 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1228 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1229 pgoff); 1230 } 1231 } else { 1232 maxsize = 0; 1233 ncount = 0; 1234 } 1235 if (ncount < count) { 1236 for (i = ncount; i < count; i++) { 1237 rtvals[i] = VM_PAGER_BAD; 1238 } 1239 } 1240 } 1241 VM_OBJECT_WUNLOCK(object); 1242 1243 /* 1244 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 1245 * rather then a bdwrite() to prevent paging I/O from saturating 1246 * the buffer cache. Dummy-up the sequential heuristic to cause 1247 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1248 * the system decides how to cluster. 1249 */ 1250 ioflags = IO_VMIO; 1251 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1252 ioflags |= IO_SYNC; 1253 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1254 ioflags |= IO_ASYNC; 1255 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1256 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1257 1258 aiov.iov_base = (caddr_t) 0; 1259 aiov.iov_len = maxsize; 1260 auio.uio_iov = &aiov; 1261 auio.uio_iovcnt = 1; 1262 auio.uio_offset = poffset; 1263 auio.uio_segflg = UIO_NOCOPY; 1264 auio.uio_rw = UIO_WRITE; 1265 auio.uio_resid = maxsize; 1266 auio.uio_td = (struct thread *) 0; 1267 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1268 PCPU_INC(cnt.v_vnodeout); 1269 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1270 1271 if (error) { 1272 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1273 printf("vnode_pager_putpages: I/O error %d\n", error); 1274 } 1275 if (auio.uio_resid) { 1276 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1277 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1278 auio.uio_resid, (u_long)ma[0]->pindex); 1279 } 1280 for (i = 0; i < ncount; i++) { 1281 rtvals[i] = VM_PAGER_OK; 1282 } 1283 return rtvals[0]; 1284 } 1285 1286 void 1287 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1288 { 1289 vm_object_t obj; 1290 int i, pos; 1291 1292 if (written == 0) 1293 return; 1294 obj = ma[0]->object; 1295 VM_OBJECT_WLOCK(obj); 1296 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1297 if (pos < trunc_page(written)) { 1298 rtvals[i] = VM_PAGER_OK; 1299 vm_page_undirty(ma[i]); 1300 } else { 1301 /* Partially written page. */ 1302 rtvals[i] = VM_PAGER_AGAIN; 1303 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1304 } 1305 } 1306 VM_OBJECT_WUNLOCK(obj); 1307 } 1308 1309 void 1310 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1311 vm_offset_t end) 1312 { 1313 struct vnode *vp; 1314 vm_ooffset_t old_wm; 1315 1316 VM_OBJECT_WLOCK(object); 1317 if (object->type != OBJT_VNODE) { 1318 VM_OBJECT_WUNLOCK(object); 1319 return; 1320 } 1321 old_wm = object->un_pager.vnp.writemappings; 1322 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1323 vp = object->handle; 1324 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1325 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1326 VOP_ADD_WRITECOUNT(vp, 1); 1327 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1328 __func__, vp, vp->v_writecount); 1329 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1330 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1331 VOP_ADD_WRITECOUNT(vp, -1); 1332 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1333 __func__, vp, vp->v_writecount); 1334 } 1335 VM_OBJECT_WUNLOCK(object); 1336 } 1337 1338 void 1339 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1340 vm_offset_t end) 1341 { 1342 struct vnode *vp; 1343 struct mount *mp; 1344 vm_offset_t inc; 1345 1346 VM_OBJECT_WLOCK(object); 1347 1348 /* 1349 * First, recheck the object type to account for the race when 1350 * the vnode is reclaimed. 1351 */ 1352 if (object->type != OBJT_VNODE) { 1353 VM_OBJECT_WUNLOCK(object); 1354 return; 1355 } 1356 1357 /* 1358 * Optimize for the case when writemappings is not going to 1359 * zero. 1360 */ 1361 inc = end - start; 1362 if (object->un_pager.vnp.writemappings != inc) { 1363 object->un_pager.vnp.writemappings -= inc; 1364 VM_OBJECT_WUNLOCK(object); 1365 return; 1366 } 1367 1368 vp = object->handle; 1369 vhold(vp); 1370 VM_OBJECT_WUNLOCK(object); 1371 mp = NULL; 1372 vn_start_write(vp, &mp, V_WAIT); 1373 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1374 1375 /* 1376 * Decrement the object's writemappings, by swapping the start 1377 * and end arguments for vnode_pager_update_writecount(). If 1378 * there was not a race with vnode reclaimation, then the 1379 * vnode's v_writecount is decremented. 1380 */ 1381 vnode_pager_update_writecount(object, end, start); 1382 VOP_UNLOCK(vp, 0); 1383 vdrop(vp); 1384 if (mp != NULL) 1385 vn_finished_write(mp); 1386 } 1387