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sys/vm/vnode_pager.c
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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: releng/9.1/sys/vm/vnode_pager.c 234466 2012-04-19 18:03:24Z mckusick $"); 55 56 #include <sys/param.h> 57 #include <sys/systm.h> 58 #include <sys/proc.h> 59 #include <sys/vnode.h> 60 #include <sys/mount.h> 61 #include <sys/bio.h> 62 #include <sys/buf.h> 63 #include <sys/vmmeter.h> 64 #include <sys/limits.h> 65 #include <sys/conf.h> 66 #include <sys/sf_buf.h> 67 68 #include <machine/atomic.h> 69 70 #include <vm/vm.h> 71 #include <vm/vm_object.h> 72 #include <vm/vm_page.h> 73 #include <vm/vm_pager.h> 74 #include <vm/vm_map.h> 75 #include <vm/vnode_pager.h> 76 #include <vm/vm_extern.h> 77 78 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 79 daddr_t *rtaddress, int *run); 80 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 81 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 82 static void vnode_pager_dealloc(vm_object_t); 83 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 84 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); 85 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 86 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 87 vm_ooffset_t, struct ucred *cred); 88 89 struct pagerops vnodepagerops = { 90 .pgo_alloc = vnode_pager_alloc, 91 .pgo_dealloc = vnode_pager_dealloc, 92 .pgo_getpages = vnode_pager_getpages, 93 .pgo_putpages = vnode_pager_putpages, 94 .pgo_haspage = vnode_pager_haspage, 95 }; 96 97 int vnode_pbuf_freecnt; 98 99 /* Create the VM system backing object for this vnode */ 100 int 101 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 102 { 103 vm_object_t object; 104 vm_ooffset_t size = isize; 105 struct vattr va; 106 107 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 108 return (0); 109 110 while ((object = vp->v_object) != NULL) { 111 VM_OBJECT_LOCK(object); 112 if (!(object->flags & OBJ_DEAD)) { 113 VM_OBJECT_UNLOCK(object); 114 return (0); 115 } 116 VOP_UNLOCK(vp, 0); 117 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 118 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0); 119 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 120 } 121 122 if (size == 0) { 123 if (vn_isdisk(vp, NULL)) { 124 size = IDX_TO_OFF(INT_MAX); 125 } else { 126 if (VOP_GETATTR(vp, &va, td->td_ucred)) 127 return (0); 128 size = va.va_size; 129 } 130 } 131 132 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 133 /* 134 * Dereference the reference we just created. This assumes 135 * that the object is associated with the vp. 136 */ 137 VM_OBJECT_LOCK(object); 138 object->ref_count--; 139 VM_OBJECT_UNLOCK(object); 140 vrele(vp); 141 142 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 143 144 return (0); 145 } 146 147 void 148 vnode_destroy_vobject(struct vnode *vp) 149 { 150 struct vm_object *obj; 151 152 obj = vp->v_object; 153 if (obj == NULL) 154 return; 155 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 156 VM_OBJECT_LOCK(obj); 157 if (obj->ref_count == 0) { 158 /* 159 * vclean() may be called twice. The first time 160 * removes the primary reference to the object, 161 * the second time goes one further and is a 162 * special-case to terminate the object. 163 * 164 * don't double-terminate the object 165 */ 166 if ((obj->flags & OBJ_DEAD) == 0) 167 vm_object_terminate(obj); 168 else 169 VM_OBJECT_UNLOCK(obj); 170 } else { 171 /* 172 * Woe to the process that tries to page now :-). 173 */ 174 vm_pager_deallocate(obj); 175 VM_OBJECT_UNLOCK(obj); 176 } 177 vp->v_object = NULL; 178 } 179 180 181 /* 182 * Allocate (or lookup) pager for a vnode. 183 * Handle is a vnode pointer. 184 * 185 * MPSAFE 186 */ 187 vm_object_t 188 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 189 vm_ooffset_t offset, struct ucred *cred) 190 { 191 vm_object_t object; 192 struct vnode *vp; 193 194 /* 195 * Pageout to vnode, no can do yet. 196 */ 197 if (handle == NULL) 198 return (NULL); 199 200 vp = (struct vnode *) handle; 201 202 /* 203 * If the object is being terminated, wait for it to 204 * go away. 205 */ 206 retry: 207 while ((object = vp->v_object) != NULL) { 208 VM_OBJECT_LOCK(object); 209 if ((object->flags & OBJ_DEAD) == 0) 210 break; 211 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 212 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); 213 } 214 215 if (vp->v_usecount == 0) 216 panic("vnode_pager_alloc: no vnode reference"); 217 218 if (object == NULL) { 219 /* 220 * Add an object of the appropriate size 221 */ 222 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 223 224 object->un_pager.vnp.vnp_size = size; 225 object->un_pager.vnp.writemappings = 0; 226 227 object->handle = handle; 228 VI_LOCK(vp); 229 if (vp->v_object != NULL) { 230 /* 231 * Object has been created while we were sleeping 232 */ 233 VI_UNLOCK(vp); 234 vm_object_destroy(object); 235 goto retry; 236 } 237 vp->v_object = object; 238 VI_UNLOCK(vp); 239 } else { 240 object->ref_count++; 241 VM_OBJECT_UNLOCK(object); 242 } 243 vref(vp); 244 return (object); 245 } 246 247 /* 248 * The object must be locked. 249 */ 250 static void 251 vnode_pager_dealloc(object) 252 vm_object_t object; 253 { 254 struct vnode *vp; 255 int refs; 256 257 vp = object->handle; 258 if (vp == NULL) 259 panic("vnode_pager_dealloc: pager already dealloced"); 260 261 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 262 vm_object_pip_wait(object, "vnpdea"); 263 refs = object->ref_count; 264 265 object->handle = NULL; 266 object->type = OBJT_DEAD; 267 if (object->flags & OBJ_DISCONNECTWNT) { 268 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 269 wakeup(object); 270 } 271 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 272 if (object->un_pager.vnp.writemappings > 0) { 273 object->un_pager.vnp.writemappings = 0; 274 vp->v_writecount--; 275 } 276 vp->v_object = NULL; 277 vp->v_vflag &= ~VV_TEXT; 278 VM_OBJECT_UNLOCK(object); 279 while (refs-- > 0) 280 vunref(vp); 281 VM_OBJECT_LOCK(object); 282 } 283 284 static boolean_t 285 vnode_pager_haspage(object, pindex, before, after) 286 vm_object_t object; 287 vm_pindex_t pindex; 288 int *before; 289 int *after; 290 { 291 struct vnode *vp = object->handle; 292 daddr_t bn; 293 int err; 294 daddr_t reqblock; 295 int poff; 296 int bsize; 297 int pagesperblock, blocksperpage; 298 int vfslocked; 299 300 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 301 /* 302 * If no vp or vp is doomed or marked transparent to VM, we do not 303 * have the page. 304 */ 305 if (vp == NULL || vp->v_iflag & VI_DOOMED) 306 return FALSE; 307 /* 308 * If the offset is beyond end of file we do 309 * not have the page. 310 */ 311 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 312 return FALSE; 313 314 bsize = vp->v_mount->mnt_stat.f_iosize; 315 pagesperblock = bsize / PAGE_SIZE; 316 blocksperpage = 0; 317 if (pagesperblock > 0) { 318 reqblock = pindex / pagesperblock; 319 } else { 320 blocksperpage = (PAGE_SIZE / bsize); 321 reqblock = pindex * blocksperpage; 322 } 323 VM_OBJECT_UNLOCK(object); 324 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 325 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 326 VFS_UNLOCK_GIANT(vfslocked); 327 VM_OBJECT_LOCK(object); 328 if (err) 329 return TRUE; 330 if (bn == -1) 331 return FALSE; 332 if (pagesperblock > 0) { 333 poff = pindex - (reqblock * pagesperblock); 334 if (before) { 335 *before *= pagesperblock; 336 *before += poff; 337 } 338 if (after) { 339 int numafter; 340 *after *= pagesperblock; 341 numafter = pagesperblock - (poff + 1); 342 if (IDX_TO_OFF(pindex + numafter) > 343 object->un_pager.vnp.vnp_size) { 344 numafter = 345 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 346 pindex; 347 } 348 *after += numafter; 349 } 350 } else { 351 if (before) { 352 *before /= blocksperpage; 353 } 354 355 if (after) { 356 *after /= blocksperpage; 357 } 358 } 359 return TRUE; 360 } 361 362 /* 363 * Lets the VM system know about a change in size for a file. 364 * We adjust our own internal size and flush any cached pages in 365 * the associated object that are affected by the size change. 366 * 367 * Note: this routine may be invoked as a result of a pager put 368 * operation (possibly at object termination time), so we must be careful. 369 */ 370 void 371 vnode_pager_setsize(vp, nsize) 372 struct vnode *vp; 373 vm_ooffset_t nsize; 374 { 375 vm_object_t object; 376 vm_page_t m; 377 vm_pindex_t nobjsize; 378 379 if ((object = vp->v_object) == NULL) 380 return; 381 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 382 VM_OBJECT_LOCK(object); 383 if (nsize == object->un_pager.vnp.vnp_size) { 384 /* 385 * Hasn't changed size 386 */ 387 VM_OBJECT_UNLOCK(object); 388 return; 389 } 390 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 391 if (nsize < object->un_pager.vnp.vnp_size) { 392 /* 393 * File has shrunk. Toss any cached pages beyond the new EOF. 394 */ 395 if (nobjsize < object->size) 396 vm_object_page_remove(object, nobjsize, object->size, 397 0); 398 /* 399 * this gets rid of garbage at the end of a page that is now 400 * only partially backed by the vnode. 401 * 402 * XXX for some reason (I don't know yet), if we take a 403 * completely invalid page and mark it partially valid 404 * it can screw up NFS reads, so we don't allow the case. 405 */ 406 if ((nsize & PAGE_MASK) && 407 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 408 m->valid != 0) { 409 int base = (int)nsize & PAGE_MASK; 410 int size = PAGE_SIZE - base; 411 412 /* 413 * Clear out partial-page garbage in case 414 * the page has been mapped. 415 */ 416 pmap_zero_page_area(m, base, size); 417 418 /* 419 * Update the valid bits to reflect the blocks that 420 * have been zeroed. Some of these valid bits may 421 * have already been set. 422 */ 423 vm_page_set_valid(m, base, size); 424 425 /* 426 * Round "base" to the next block boundary so that the 427 * dirty bit for a partially zeroed block is not 428 * cleared. 429 */ 430 base = roundup2(base, DEV_BSIZE); 431 432 /* 433 * Clear out partial-page dirty bits. 434 * 435 * note that we do not clear out the valid 436 * bits. This would prevent bogus_page 437 * replacement from working properly. 438 */ 439 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 440 } else if ((nsize & PAGE_MASK) && 441 __predict_false(object->cache != NULL)) { 442 vm_page_cache_free(object, OFF_TO_IDX(nsize), 443 nobjsize); 444 } 445 } 446 object->un_pager.vnp.vnp_size = nsize; 447 object->size = nobjsize; 448 VM_OBJECT_UNLOCK(object); 449 } 450 451 /* 452 * calculate the linear (byte) disk address of specified virtual 453 * file address 454 */ 455 static int 456 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 457 int *run) 458 { 459 int bsize; 460 int err; 461 daddr_t vblock; 462 daddr_t voffset; 463 464 if (address < 0) 465 return -1; 466 467 if (vp->v_iflag & VI_DOOMED) 468 return -1; 469 470 bsize = vp->v_mount->mnt_stat.f_iosize; 471 vblock = address / bsize; 472 voffset = address % bsize; 473 474 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 475 if (err == 0) { 476 if (*rtaddress != -1) 477 *rtaddress += voffset / DEV_BSIZE; 478 if (run) { 479 *run += 1; 480 *run *= bsize/PAGE_SIZE; 481 *run -= voffset/PAGE_SIZE; 482 } 483 } 484 485 return (err); 486 } 487 488 /* 489 * small block filesystem vnode pager input 490 */ 491 static int 492 vnode_pager_input_smlfs(object, m) 493 vm_object_t object; 494 vm_page_t m; 495 { 496 struct vnode *vp; 497 struct bufobj *bo; 498 struct buf *bp; 499 struct sf_buf *sf; 500 daddr_t fileaddr; 501 vm_offset_t bsize; 502 vm_page_bits_t bits; 503 int error, i; 504 505 error = 0; 506 vp = object->handle; 507 if (vp->v_iflag & VI_DOOMED) 508 return VM_PAGER_BAD; 509 510 bsize = vp->v_mount->mnt_stat.f_iosize; 511 512 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 513 514 sf = sf_buf_alloc(m, 0); 515 516 for (i = 0; i < PAGE_SIZE / bsize; i++) { 517 vm_ooffset_t address; 518 519 bits = vm_page_bits(i * bsize, bsize); 520 if (m->valid & bits) 521 continue; 522 523 address = IDX_TO_OFF(m->pindex) + i * bsize; 524 if (address >= object->un_pager.vnp.vnp_size) { 525 fileaddr = -1; 526 } else { 527 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 528 if (error) 529 break; 530 } 531 if (fileaddr != -1) { 532 bp = getpbuf(&vnode_pbuf_freecnt); 533 534 /* build a minimal buffer header */ 535 bp->b_iocmd = BIO_READ; 536 bp->b_iodone = bdone; 537 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 538 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 539 bp->b_rcred = crhold(curthread->td_ucred); 540 bp->b_wcred = crhold(curthread->td_ucred); 541 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 542 bp->b_blkno = fileaddr; 543 pbgetbo(bo, bp); 544 bp->b_vp = vp; 545 bp->b_bcount = bsize; 546 bp->b_bufsize = bsize; 547 bp->b_runningbufspace = bp->b_bufsize; 548 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 549 550 /* do the input */ 551 bp->b_iooffset = dbtob(bp->b_blkno); 552 bstrategy(bp); 553 554 bwait(bp, PVM, "vnsrd"); 555 556 if ((bp->b_ioflags & BIO_ERROR) != 0) 557 error = EIO; 558 559 /* 560 * free the buffer header back to the swap buffer pool 561 */ 562 bp->b_vp = NULL; 563 pbrelbo(bp); 564 relpbuf(bp, &vnode_pbuf_freecnt); 565 if (error) 566 break; 567 } else 568 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 569 KASSERT((m->dirty & bits) == 0, 570 ("vnode_pager_input_smlfs: page %p is dirty", m)); 571 VM_OBJECT_LOCK(object); 572 m->valid |= bits; 573 VM_OBJECT_UNLOCK(object); 574 } 575 sf_buf_free(sf); 576 if (error) { 577 return VM_PAGER_ERROR; 578 } 579 return VM_PAGER_OK; 580 } 581 582 /* 583 * old style vnode pager input routine 584 */ 585 static int 586 vnode_pager_input_old(object, m) 587 vm_object_t object; 588 vm_page_t m; 589 { 590 struct uio auio; 591 struct iovec aiov; 592 int error; 593 int size; 594 struct sf_buf *sf; 595 struct vnode *vp; 596 597 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 598 error = 0; 599 600 /* 601 * Return failure if beyond current EOF 602 */ 603 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 604 return VM_PAGER_BAD; 605 } else { 606 size = PAGE_SIZE; 607 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 608 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 609 vp = object->handle; 610 VM_OBJECT_UNLOCK(object); 611 612 /* 613 * Allocate a kernel virtual address and initialize so that 614 * we can use VOP_READ/WRITE routines. 615 */ 616 sf = sf_buf_alloc(m, 0); 617 618 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 619 aiov.iov_len = size; 620 auio.uio_iov = &aiov; 621 auio.uio_iovcnt = 1; 622 auio.uio_offset = IDX_TO_OFF(m->pindex); 623 auio.uio_segflg = UIO_SYSSPACE; 624 auio.uio_rw = UIO_READ; 625 auio.uio_resid = size; 626 auio.uio_td = curthread; 627 628 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 629 if (!error) { 630 int count = size - auio.uio_resid; 631 632 if (count == 0) 633 error = EINVAL; 634 else if (count != PAGE_SIZE) 635 bzero((caddr_t)sf_buf_kva(sf) + count, 636 PAGE_SIZE - count); 637 } 638 sf_buf_free(sf); 639 640 VM_OBJECT_LOCK(object); 641 } 642 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 643 if (!error) 644 m->valid = VM_PAGE_BITS_ALL; 645 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 646 } 647 648 /* 649 * generic vnode pager input routine 650 */ 651 652 /* 653 * Local media VFS's that do not implement their own VOP_GETPAGES 654 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 655 * to implement the previous behaviour. 656 * 657 * All other FS's should use the bypass to get to the local media 658 * backing vp's VOP_GETPAGES. 659 */ 660 static int 661 vnode_pager_getpages(object, m, count, reqpage) 662 vm_object_t object; 663 vm_page_t *m; 664 int count; 665 int reqpage; 666 { 667 int rtval; 668 struct vnode *vp; 669 int bytes = count * PAGE_SIZE; 670 int vfslocked; 671 672 vp = object->handle; 673 VM_OBJECT_UNLOCK(object); 674 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 675 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 676 KASSERT(rtval != EOPNOTSUPP, 677 ("vnode_pager: FS getpages not implemented\n")); 678 VFS_UNLOCK_GIANT(vfslocked); 679 VM_OBJECT_LOCK(object); 680 return rtval; 681 } 682 683 /* 684 * This is now called from local media FS's to operate against their 685 * own vnodes if they fail to implement VOP_GETPAGES. 686 */ 687 int 688 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 689 struct vnode *vp; 690 vm_page_t *m; 691 int bytecount; 692 int reqpage; 693 { 694 vm_object_t object; 695 vm_offset_t kva; 696 off_t foff, tfoff, nextoff; 697 int i, j, size, bsize, first; 698 daddr_t firstaddr, reqblock; 699 struct bufobj *bo; 700 int runpg; 701 int runend; 702 struct buf *bp; 703 int count; 704 int error; 705 706 object = vp->v_object; 707 count = bytecount / PAGE_SIZE; 708 709 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 710 ("vnode_pager_generic_getpages does not support devices")); 711 if (vp->v_iflag & VI_DOOMED) 712 return VM_PAGER_BAD; 713 714 bsize = vp->v_mount->mnt_stat.f_iosize; 715 716 /* get the UNDERLYING device for the file with VOP_BMAP() */ 717 718 /* 719 * originally, we did not check for an error return value -- assuming 720 * an fs always has a bmap entry point -- that assumption is wrong!!! 721 */ 722 foff = IDX_TO_OFF(m[reqpage]->pindex); 723 724 /* 725 * if we can't bmap, use old VOP code 726 */ 727 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL); 728 if (error == EOPNOTSUPP) { 729 VM_OBJECT_LOCK(object); 730 731 for (i = 0; i < count; i++) 732 if (i != reqpage) { 733 vm_page_lock(m[i]); 734 vm_page_free(m[i]); 735 vm_page_unlock(m[i]); 736 } 737 PCPU_INC(cnt.v_vnodein); 738 PCPU_INC(cnt.v_vnodepgsin); 739 error = vnode_pager_input_old(object, m[reqpage]); 740 VM_OBJECT_UNLOCK(object); 741 return (error); 742 } else if (error != 0) { 743 VM_OBJECT_LOCK(object); 744 for (i = 0; i < count; i++) 745 if (i != reqpage) { 746 vm_page_lock(m[i]); 747 vm_page_free(m[i]); 748 vm_page_unlock(m[i]); 749 } 750 VM_OBJECT_UNLOCK(object); 751 return (VM_PAGER_ERROR); 752 753 /* 754 * if the blocksize is smaller than a page size, then use 755 * special small filesystem code. NFS sometimes has a small 756 * blocksize, but it can handle large reads itself. 757 */ 758 } else if ((PAGE_SIZE / bsize) > 1 && 759 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 760 VM_OBJECT_LOCK(object); 761 for (i = 0; i < count; i++) 762 if (i != reqpage) { 763 vm_page_lock(m[i]); 764 vm_page_free(m[i]); 765 vm_page_unlock(m[i]); 766 } 767 VM_OBJECT_UNLOCK(object); 768 PCPU_INC(cnt.v_vnodein); 769 PCPU_INC(cnt.v_vnodepgsin); 770 return vnode_pager_input_smlfs(object, m[reqpage]); 771 } 772 773 /* 774 * If we have a completely valid page available to us, we can 775 * clean up and return. Otherwise we have to re-read the 776 * media. 777 */ 778 VM_OBJECT_LOCK(object); 779 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 780 for (i = 0; i < count; i++) 781 if (i != reqpage) { 782 vm_page_lock(m[i]); 783 vm_page_free(m[i]); 784 vm_page_unlock(m[i]); 785 } 786 VM_OBJECT_UNLOCK(object); 787 return VM_PAGER_OK; 788 } else if (reqblock == -1) { 789 pmap_zero_page(m[reqpage]); 790 KASSERT(m[reqpage]->dirty == 0, 791 ("vnode_pager_generic_getpages: page %p is dirty", m)); 792 m[reqpage]->valid = VM_PAGE_BITS_ALL; 793 for (i = 0; i < count; i++) 794 if (i != reqpage) { 795 vm_page_lock(m[i]); 796 vm_page_free(m[i]); 797 vm_page_unlock(m[i]); 798 } 799 VM_OBJECT_UNLOCK(object); 800 return (VM_PAGER_OK); 801 } 802 m[reqpage]->valid = 0; 803 VM_OBJECT_UNLOCK(object); 804 805 /* 806 * here on direct device I/O 807 */ 808 firstaddr = -1; 809 810 /* 811 * calculate the run that includes the required page 812 */ 813 for (first = 0, i = 0; i < count; i = runend) { 814 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr, 815 &runpg) != 0) { 816 VM_OBJECT_LOCK(object); 817 for (; i < count; i++) 818 if (i != reqpage) { 819 vm_page_lock(m[i]); 820 vm_page_free(m[i]); 821 vm_page_unlock(m[i]); 822 } 823 VM_OBJECT_UNLOCK(object); 824 return (VM_PAGER_ERROR); 825 } 826 if (firstaddr == -1) { 827 VM_OBJECT_LOCK(object); 828 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 829 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 830 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 831 (uintmax_t)foff, 832 (uintmax_t) 833 (object->un_pager.vnp.vnp_size >> 32), 834 (uintmax_t)object->un_pager.vnp.vnp_size); 835 } 836 vm_page_lock(m[i]); 837 vm_page_free(m[i]); 838 vm_page_unlock(m[i]); 839 VM_OBJECT_UNLOCK(object); 840 runend = i + 1; 841 first = runend; 842 continue; 843 } 844 runend = i + runpg; 845 if (runend <= reqpage) { 846 VM_OBJECT_LOCK(object); 847 for (j = i; j < runend; j++) { 848 vm_page_lock(m[j]); 849 vm_page_free(m[j]); 850 vm_page_unlock(m[j]); 851 } 852 VM_OBJECT_UNLOCK(object); 853 } else { 854 if (runpg < (count - first)) { 855 VM_OBJECT_LOCK(object); 856 for (i = first + runpg; i < count; i++) { 857 vm_page_lock(m[i]); 858 vm_page_free(m[i]); 859 vm_page_unlock(m[i]); 860 } 861 VM_OBJECT_UNLOCK(object); 862 count = first + runpg; 863 } 864 break; 865 } 866 first = runend; 867 } 868 869 /* 870 * the first and last page have been calculated now, move input pages 871 * to be zero based... 872 */ 873 if (first != 0) { 874 m += first; 875 count -= first; 876 reqpage -= first; 877 } 878 879 /* 880 * calculate the file virtual address for the transfer 881 */ 882 foff = IDX_TO_OFF(m[0]->pindex); 883 884 /* 885 * calculate the size of the transfer 886 */ 887 size = count * PAGE_SIZE; 888 KASSERT(count > 0, ("zero count")); 889 if ((foff + size) > object->un_pager.vnp.vnp_size) 890 size = object->un_pager.vnp.vnp_size - foff; 891 KASSERT(size > 0, ("zero size")); 892 893 /* 894 * round up physical size for real devices. 895 */ 896 if (1) { 897 int secmask = bo->bo_bsize - 1; 898 KASSERT(secmask < PAGE_SIZE && secmask > 0, 899 ("vnode_pager_generic_getpages: sector size %d too large", 900 secmask + 1)); 901 size = (size + secmask) & ~secmask; 902 } 903 904 bp = getpbuf(&vnode_pbuf_freecnt); 905 kva = (vm_offset_t) bp->b_data; 906 907 /* 908 * and map the pages to be read into the kva 909 */ 910 pmap_qenter(kva, m, count); 911 912 /* build a minimal buffer header */ 913 bp->b_iocmd = BIO_READ; 914 bp->b_iodone = bdone; 915 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 916 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 917 bp->b_rcred = crhold(curthread->td_ucred); 918 bp->b_wcred = crhold(curthread->td_ucred); 919 bp->b_blkno = firstaddr; 920 pbgetbo(bo, bp); 921 bp->b_vp = vp; 922 bp->b_bcount = size; 923 bp->b_bufsize = size; 924 bp->b_runningbufspace = bp->b_bufsize; 925 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 926 927 PCPU_INC(cnt.v_vnodein); 928 PCPU_ADD(cnt.v_vnodepgsin, count); 929 930 /* do the input */ 931 bp->b_iooffset = dbtob(bp->b_blkno); 932 bstrategy(bp); 933 934 bwait(bp, PVM, "vnread"); 935 936 if ((bp->b_ioflags & BIO_ERROR) != 0) 937 error = EIO; 938 939 if (!error) { 940 if (size != count * PAGE_SIZE) 941 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 942 } 943 pmap_qremove(kva, count); 944 945 /* 946 * free the buffer header back to the swap buffer pool 947 */ 948 bp->b_vp = NULL; 949 pbrelbo(bp); 950 relpbuf(bp, &vnode_pbuf_freecnt); 951 952 VM_OBJECT_LOCK(object); 953 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 954 vm_page_t mt; 955 956 nextoff = tfoff + PAGE_SIZE; 957 mt = m[i]; 958 959 if (nextoff <= object->un_pager.vnp.vnp_size) { 960 /* 961 * Read filled up entire page. 962 */ 963 mt->valid = VM_PAGE_BITS_ALL; 964 KASSERT(mt->dirty == 0, 965 ("vnode_pager_generic_getpages: page %p is dirty", 966 mt)); 967 KASSERT(!pmap_page_is_mapped(mt), 968 ("vnode_pager_generic_getpages: page %p is mapped", 969 mt)); 970 } else { 971 /* 972 * Read did not fill up entire page. 973 * 974 * Currently we do not set the entire page valid, 975 * we just try to clear the piece that we couldn't 976 * read. 977 */ 978 vm_page_set_valid(mt, 0, 979 object->un_pager.vnp.vnp_size - tfoff); 980 KASSERT((mt->dirty & vm_page_bits(0, 981 object->un_pager.vnp.vnp_size - tfoff)) == 0, 982 ("vnode_pager_generic_getpages: page %p is dirty", 983 mt)); 984 } 985 986 if (i != reqpage) { 987 988 /* 989 * whether or not to leave the page activated is up in 990 * the air, but we should put the page on a page queue 991 * somewhere. (it already is in the object). Result: 992 * It appears that empirical results show that 993 * deactivating pages is best. 994 */ 995 996 /* 997 * just in case someone was asking for this page we 998 * now tell them that it is ok to use 999 */ 1000 if (!error) { 1001 if (mt->oflags & VPO_WANTED) { 1002 vm_page_lock(mt); 1003 vm_page_activate(mt); 1004 vm_page_unlock(mt); 1005 } else { 1006 vm_page_lock(mt); 1007 vm_page_deactivate(mt); 1008 vm_page_unlock(mt); 1009 } 1010 vm_page_wakeup(mt); 1011 } else { 1012 vm_page_lock(mt); 1013 vm_page_free(mt); 1014 vm_page_unlock(mt); 1015 } 1016 } 1017 } 1018 VM_OBJECT_UNLOCK(object); 1019 if (error) { 1020 printf("vnode_pager_getpages: I/O read error\n"); 1021 } 1022 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 1023 } 1024 1025 /* 1026 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1027 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1028 * vnode_pager_generic_putpages() to implement the previous behaviour. 1029 * 1030 * All other FS's should use the bypass to get to the local media 1031 * backing vp's VOP_PUTPAGES. 1032 */ 1033 static void 1034 vnode_pager_putpages(object, m, count, sync, rtvals) 1035 vm_object_t object; 1036 vm_page_t *m; 1037 int count; 1038 boolean_t sync; 1039 int *rtvals; 1040 { 1041 int rtval; 1042 struct vnode *vp; 1043 int bytes = count * PAGE_SIZE; 1044 1045 /* 1046 * Force synchronous operation if we are extremely low on memory 1047 * to prevent a low-memory deadlock. VOP operations often need to 1048 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1049 * operation ). The swapper handles the case by limiting the amount 1050 * of asynchronous I/O, but that sort of solution doesn't scale well 1051 * for the vnode pager without a lot of work. 1052 * 1053 * Also, the backing vnode's iodone routine may not wake the pageout 1054 * daemon up. This should be probably be addressed XXX. 1055 */ 1056 1057 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 1058 sync |= OBJPC_SYNC; 1059 1060 /* 1061 * Call device-specific putpages function 1062 */ 1063 vp = object->handle; 1064 VM_OBJECT_UNLOCK(object); 1065 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 1066 KASSERT(rtval != EOPNOTSUPP, 1067 ("vnode_pager: stale FS putpages\n")); 1068 VM_OBJECT_LOCK(object); 1069 } 1070 1071 1072 /* 1073 * This is now called from local media FS's to operate against their 1074 * own vnodes if they fail to implement VOP_PUTPAGES. 1075 * 1076 * This is typically called indirectly via the pageout daemon and 1077 * clustering has already typically occured, so in general we ask the 1078 * underlying filesystem to write the data out asynchronously rather 1079 * then delayed. 1080 */ 1081 int 1082 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1083 int flags, int *rtvals) 1084 { 1085 int i; 1086 vm_object_t object; 1087 vm_page_t m; 1088 int count; 1089 1090 int maxsize, ncount; 1091 vm_ooffset_t poffset; 1092 struct uio auio; 1093 struct iovec aiov; 1094 int error; 1095 int ioflags; 1096 int ppscheck = 0; 1097 static struct timeval lastfail; 1098 static int curfail; 1099 1100 object = vp->v_object; 1101 count = bytecount / PAGE_SIZE; 1102 1103 for (i = 0; i < count; i++) 1104 rtvals[i] = VM_PAGER_ERROR; 1105 1106 if ((int64_t)ma[0]->pindex < 0) { 1107 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1108 (long)ma[0]->pindex, (u_long)ma[0]->dirty); 1109 rtvals[0] = VM_PAGER_BAD; 1110 return VM_PAGER_BAD; 1111 } 1112 1113 maxsize = count * PAGE_SIZE; 1114 ncount = count; 1115 1116 poffset = IDX_TO_OFF(ma[0]->pindex); 1117 1118 /* 1119 * If the page-aligned write is larger then the actual file we 1120 * have to invalidate pages occuring beyond the file EOF. However, 1121 * there is an edge case where a file may not be page-aligned where 1122 * the last page is partially invalid. In this case the filesystem 1123 * may not properly clear the dirty bits for the entire page (which 1124 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1125 * With the page locked we are free to fix-up the dirty bits here. 1126 * 1127 * We do not under any circumstances truncate the valid bits, as 1128 * this will screw up bogus page replacement. 1129 */ 1130 VM_OBJECT_LOCK(object); 1131 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1132 if (object->un_pager.vnp.vnp_size > poffset) { 1133 int pgoff; 1134 1135 maxsize = object->un_pager.vnp.vnp_size - poffset; 1136 ncount = btoc(maxsize); 1137 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1138 /* 1139 * If the object is locked and the following 1140 * conditions hold, then the page's dirty 1141 * field cannot be concurrently changed by a 1142 * pmap operation. 1143 */ 1144 m = ma[ncount - 1]; 1145 KASSERT(m->busy > 0, 1146 ("vnode_pager_generic_putpages: page %p is not busy", m)); 1147 KASSERT((m->aflags & PGA_WRITEABLE) == 0, 1148 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1149 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1150 pgoff); 1151 } 1152 } else { 1153 maxsize = 0; 1154 ncount = 0; 1155 } 1156 if (ncount < count) { 1157 for (i = ncount; i < count; i++) { 1158 rtvals[i] = VM_PAGER_BAD; 1159 } 1160 } 1161 } 1162 VM_OBJECT_UNLOCK(object); 1163 1164 /* 1165 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1166 * rather then a bdwrite() to prevent paging I/O from saturating 1167 * the buffer cache. Dummy-up the sequential heuristic to cause 1168 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1169 * the system decides how to cluster. 1170 */ 1171 ioflags = IO_VMIO; 1172 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1173 ioflags |= IO_SYNC; 1174 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1175 ioflags |= IO_ASYNC; 1176 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1177 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1178 1179 aiov.iov_base = (caddr_t) 0; 1180 aiov.iov_len = maxsize; 1181 auio.uio_iov = &aiov; 1182 auio.uio_iovcnt = 1; 1183 auio.uio_offset = poffset; 1184 auio.uio_segflg = UIO_NOCOPY; 1185 auio.uio_rw = UIO_WRITE; 1186 auio.uio_resid = maxsize; 1187 auio.uio_td = (struct thread *) 0; 1188 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1189 PCPU_INC(cnt.v_vnodeout); 1190 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1191 1192 if (error) { 1193 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1194 printf("vnode_pager_putpages: I/O error %d\n", error); 1195 } 1196 if (auio.uio_resid) { 1197 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1198 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1199 auio.uio_resid, (u_long)ma[0]->pindex); 1200 } 1201 for (i = 0; i < ncount; i++) { 1202 rtvals[i] = VM_PAGER_OK; 1203 } 1204 return rtvals[0]; 1205 } 1206 1207 void 1208 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1209 { 1210 vm_object_t obj; 1211 int i, pos; 1212 1213 if (written == 0) 1214 return; 1215 obj = ma[0]->object; 1216 VM_OBJECT_LOCK(obj); 1217 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1218 if (pos < trunc_page(written)) { 1219 rtvals[i] = VM_PAGER_OK; 1220 vm_page_undirty(ma[i]); 1221 } else { 1222 /* Partially written page. */ 1223 rtvals[i] = VM_PAGER_AGAIN; 1224 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1225 } 1226 } 1227 VM_OBJECT_UNLOCK(obj); 1228 } 1229 1230 void 1231 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1232 vm_offset_t end) 1233 { 1234 struct vnode *vp; 1235 vm_ooffset_t old_wm; 1236 1237 VM_OBJECT_LOCK(object); 1238 if (object->type != OBJT_VNODE) { 1239 VM_OBJECT_UNLOCK(object); 1240 return; 1241 } 1242 old_wm = object->un_pager.vnp.writemappings; 1243 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1244 vp = object->handle; 1245 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1246 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1247 vp->v_writecount++; 1248 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1249 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1250 vp->v_writecount--; 1251 } 1252 VM_OBJECT_UNLOCK(object); 1253 } 1254 1255 void 1256 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1257 vm_offset_t end) 1258 { 1259 struct vnode *vp; 1260 struct mount *mp; 1261 vm_offset_t inc; 1262 int vfslocked; 1263 1264 VM_OBJECT_LOCK(object); 1265 1266 /* 1267 * First, recheck the object type to account for the race when 1268 * the vnode is reclaimed. 1269 */ 1270 if (object->type != OBJT_VNODE) { 1271 VM_OBJECT_UNLOCK(object); 1272 return; 1273 } 1274 1275 /* 1276 * Optimize for the case when writemappings is not going to 1277 * zero. 1278 */ 1279 inc = end - start; 1280 if (object->un_pager.vnp.writemappings != inc) { 1281 object->un_pager.vnp.writemappings -= inc; 1282 VM_OBJECT_UNLOCK(object); 1283 return; 1284 } 1285 1286 vp = object->handle; 1287 vhold(vp); 1288 VM_OBJECT_UNLOCK(object); 1289 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1290 mp = NULL; 1291 vn_start_write(vp, &mp, V_WAIT); 1292 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1293 1294 /* 1295 * Decrement the object's writemappings, by swapping the start 1296 * and end arguments for vnode_pager_update_writecount(). If 1297 * there was not a race with vnode reclaimation, then the 1298 * vnode's v_writecount is decremented. 1299 */ 1300 vnode_pager_update_writecount(object, end, start); 1301 VOP_UNLOCK(vp, 0); 1302 vdrop(vp); 1303 if (mp != NULL) 1304 vn_finished_write(mp); 1305 VFS_UNLOCK_GIANT(vfslocked); 1306 }
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