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 * $FreeBSD$ 42 */ 43 44 /* 45 * Page to/from files (vnodes). 46 */ 47 48 /* 49 * TODO: 50 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 51 * greatly re-simplify the vnode_pager. 52 */ 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/proc.h> 57 #include <sys/vnode.h> 58 #include <sys/mount.h> 59 #include <sys/bio.h> 60 #include <sys/buf.h> 61 #include <sys/vmmeter.h> 62 #include <sys/conf.h> 63 64 #include <vm/vm.h> 65 #include <vm/vm_object.h> 66 #include <vm/vm_page.h> 67 #include <vm/vm_pager.h> 68 #include <vm/vm_map.h> 69 #include <vm/vnode_pager.h> 70 #include <vm/vm_extern.h> 71 72 static void vnode_pager_init __P((void)); 73 static vm_offset_t vnode_pager_addr __P((struct vnode *vp, vm_ooffset_t address, 74 int *run)); 75 static void vnode_pager_iodone __P((struct buf *bp)); 76 static int vnode_pager_input_smlfs __P((vm_object_t object, vm_page_t m)); 77 static int vnode_pager_input_old __P((vm_object_t object, vm_page_t m)); 78 static void vnode_pager_dealloc __P((vm_object_t)); 79 static int vnode_pager_getpages __P((vm_object_t, vm_page_t *, int, int)); 80 static void vnode_pager_putpages __P((vm_object_t, vm_page_t *, int, boolean_t, int *)); 81 static boolean_t vnode_pager_haspage __P((vm_object_t, vm_pindex_t, int *, int *)); 82 83 struct pagerops vnodepagerops = { 84 vnode_pager_init, 85 vnode_pager_alloc, 86 vnode_pager_dealloc, 87 vnode_pager_getpages, 88 vnode_pager_putpages, 89 vnode_pager_haspage, 90 NULL 91 }; 92 93 int vnode_pbuf_freecnt; 94 95 void 96 vnode_pager_init(void) 97 { 98 99 vnode_pbuf_freecnt = nswbuf / 2 + 1; 100 } 101 102 /* 103 * Allocate (or lookup) pager for a vnode. 104 * Handle is a vnode pointer. 105 */ 106 vm_object_t 107 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 108 vm_ooffset_t offset) 109 { 110 vm_object_t object; 111 struct vnode *vp; 112 113 GIANT_REQUIRED; 114 115 /* 116 * Pageout to vnode, no can do yet. 117 */ 118 if (handle == NULL) 119 return (NULL); 120 121 vp = (struct vnode *) handle; 122 123 /* 124 * Prevent race condition when allocating the object. This 125 * can happen with NFS vnodes since the nfsnode isn't locked. 126 */ 127 while (vp->v_flag & VOLOCK) { 128 vp->v_flag |= VOWANT; 129 tsleep(vp, PVM, "vnpobj", 0); 130 } 131 vp->v_flag |= VOLOCK; 132 133 /* 134 * If the object is being terminated, wait for it to 135 * go away. 136 */ 137 while (((object = vp->v_object) != NULL) && 138 (object->flags & OBJ_DEAD)) { 139 tsleep(object, PVM, "vadead", 0); 140 } 141 142 if (vp->v_usecount == 0) 143 panic("vnode_pager_alloc: no vnode reference"); 144 145 if (object == NULL) { 146 /* 147 * And an object of the appropriate size 148 */ 149 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 150 object->flags = 0; 151 152 object->un_pager.vnp.vnp_size = size; 153 154 object->handle = handle; 155 vp->v_object = object; 156 vp->v_usecount++; 157 } else { 158 object->ref_count++; 159 vp->v_usecount++; 160 } 161 162 vp->v_flag &= ~VOLOCK; 163 if (vp->v_flag & VOWANT) { 164 vp->v_flag &= ~VOWANT; 165 wakeup(vp); 166 } 167 return (object); 168 } 169 170 static void 171 vnode_pager_dealloc(object) 172 vm_object_t object; 173 { 174 struct vnode *vp = object->handle; 175 176 GIANT_REQUIRED; 177 if (vp == NULL) 178 panic("vnode_pager_dealloc: pager already dealloced"); 179 180 vm_object_pip_wait(object, "vnpdea"); 181 182 object->handle = NULL; 183 object->type = OBJT_DEAD; 184 vp->v_object = NULL; 185 vp->v_flag &= ~(VTEXT | VOBJBUF); 186 } 187 188 static boolean_t 189 vnode_pager_haspage(object, pindex, before, after) 190 vm_object_t object; 191 vm_pindex_t pindex; 192 int *before; 193 int *after; 194 { 195 struct vnode *vp = object->handle; 196 daddr_t bn; 197 int err; 198 daddr_t reqblock; 199 int poff; 200 int bsize; 201 int pagesperblock, blocksperpage; 202 203 GIANT_REQUIRED; 204 /* 205 * If no vp or vp is doomed or marked transparent to VM, we do not 206 * have the page. 207 */ 208 if ((vp == NULL) || (vp->v_flag & VDOOMED)) 209 return FALSE; 210 211 /* 212 * If filesystem no longer mounted or offset beyond end of file we do 213 * not have the page. 214 */ 215 if ((vp->v_mount == NULL) || 216 (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)) 217 return FALSE; 218 219 bsize = vp->v_mount->mnt_stat.f_iosize; 220 pagesperblock = bsize / PAGE_SIZE; 221 blocksperpage = 0; 222 if (pagesperblock > 0) { 223 reqblock = pindex / pagesperblock; 224 } else { 225 blocksperpage = (PAGE_SIZE / bsize); 226 reqblock = pindex * blocksperpage; 227 } 228 err = VOP_BMAP(vp, reqblock, (struct vnode **) 0, &bn, 229 after, before); 230 if (err) 231 return TRUE; 232 if ( bn == -1) 233 return FALSE; 234 if (pagesperblock > 0) { 235 poff = pindex - (reqblock * pagesperblock); 236 if (before) { 237 *before *= pagesperblock; 238 *before += poff; 239 } 240 if (after) { 241 int numafter; 242 *after *= pagesperblock; 243 numafter = pagesperblock - (poff + 1); 244 if (IDX_TO_OFF(pindex + numafter) > object->un_pager.vnp.vnp_size) { 245 numafter = OFF_TO_IDX((object->un_pager.vnp.vnp_size - IDX_TO_OFF(pindex))); 246 } 247 *after += numafter; 248 } 249 } else { 250 if (before) { 251 *before /= blocksperpage; 252 } 253 254 if (after) { 255 *after /= blocksperpage; 256 } 257 } 258 return TRUE; 259 } 260 261 /* 262 * Lets the VM system know about a change in size for a file. 263 * We adjust our own internal size and flush any cached pages in 264 * the associated object that are affected by the size change. 265 * 266 * Note: this routine may be invoked as a result of a pager put 267 * operation (possibly at object termination time), so we must be careful. 268 */ 269 void 270 vnode_pager_setsize(vp, nsize) 271 struct vnode *vp; 272 vm_ooffset_t nsize; 273 { 274 vm_pindex_t nobjsize; 275 vm_object_t object = vp->v_object; 276 277 GIANT_REQUIRED; 278 279 if (object == NULL) 280 return; 281 282 /* 283 * Hasn't changed size 284 */ 285 if (nsize == object->un_pager.vnp.vnp_size) 286 return; 287 288 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 289 290 /* 291 * File has shrunk. Toss any cached pages beyond the new EOF. 292 */ 293 if (nsize < object->un_pager.vnp.vnp_size) { 294 vm_freeze_copyopts(object, OFF_TO_IDX(nsize), object->size); 295 if (nobjsize < object->size) { 296 vm_object_page_remove(object, nobjsize, object->size, 297 FALSE); 298 } 299 /* 300 * this gets rid of garbage at the end of a page that is now 301 * only partially backed by the vnode. 302 * 303 * XXX for some reason (I don't know yet), if we take a 304 * completely invalid page and mark it partially valid 305 * it can screw up NFS reads, so we don't allow the case. 306 */ 307 if (nsize & PAGE_MASK) { 308 vm_offset_t kva; 309 vm_page_t m; 310 311 m = vm_page_lookup(object, OFF_TO_IDX(nsize)); 312 if (m && m->valid) { 313 int base = (int)nsize & PAGE_MASK; 314 int size = PAGE_SIZE - base; 315 316 /* 317 * Clear out partial-page garbage in case 318 * the page has been mapped. 319 */ 320 kva = vm_pager_map_page(m); 321 bzero((caddr_t)kva + base, size); 322 vm_pager_unmap_page(kva); 323 324 /* 325 * XXX work around SMP data integrity race 326 * by unmapping the page from user processes. 327 * The garbage we just cleared may be mapped 328 * to a user process running on another cpu 329 * and this code is not running through normal 330 * I/O channels which handle SMP issues for 331 * us, so unmap page to synchronize all cpus. 332 * 333 * XXX should vm_pager_unmap_page() have 334 * dealt with this? 335 */ 336 vm_page_protect(m, VM_PROT_NONE); 337 338 /* 339 * Clear out partial-page dirty bits. This 340 * has the side effect of setting the valid 341 * bits, but that is ok. There are a bunch 342 * of places in the VM system where we expected 343 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 344 * case is one of them. If the page is still 345 * partially dirty, make it fully dirty. 346 * 347 * note that we do not clear out the valid 348 * bits. This would prevent bogus_page 349 * replacement from working properly. 350 */ 351 vm_page_set_validclean(m, base, size); 352 if (m->dirty != 0) 353 m->dirty = VM_PAGE_BITS_ALL; 354 } 355 } 356 } 357 object->un_pager.vnp.vnp_size = nsize; 358 object->size = nobjsize; 359 } 360 361 /* 362 * calculate the linear (byte) disk address of specified virtual 363 * file address 364 */ 365 static vm_offset_t 366 vnode_pager_addr(vp, address, run) 367 struct vnode *vp; 368 vm_ooffset_t address; 369 int *run; 370 { 371 int rtaddress; 372 int bsize; 373 daddr_t block; 374 struct vnode *rtvp; 375 int err; 376 daddr_t vblock; 377 int voffset; 378 379 GIANT_REQUIRED; 380 if ((int) address < 0) 381 return -1; 382 383 if (vp->v_mount == NULL) 384 return -1; 385 386 bsize = vp->v_mount->mnt_stat.f_iosize; 387 vblock = address / bsize; 388 voffset = address % bsize; 389 390 err = VOP_BMAP(vp, vblock, &rtvp, &block, run, NULL); 391 392 if (err || (block == -1)) 393 rtaddress = -1; 394 else { 395 rtaddress = block + voffset / DEV_BSIZE; 396 if( run) { 397 *run += 1; 398 *run *= bsize/PAGE_SIZE; 399 *run -= voffset/PAGE_SIZE; 400 } 401 } 402 403 return rtaddress; 404 } 405 406 /* 407 * interrupt routine for I/O completion 408 */ 409 static void 410 vnode_pager_iodone(bp) 411 struct buf *bp; 412 { 413 bp->b_flags |= B_DONE; 414 wakeup(bp); 415 } 416 417 /* 418 * small block file system vnode pager input 419 */ 420 static int 421 vnode_pager_input_smlfs(object, m) 422 vm_object_t object; 423 vm_page_t m; 424 { 425 int i; 426 int s; 427 struct vnode *dp, *vp; 428 struct buf *bp; 429 vm_offset_t kva; 430 int fileaddr; 431 vm_offset_t bsize; 432 int error = 0; 433 434 GIANT_REQUIRED; 435 436 vp = object->handle; 437 if (vp->v_mount == NULL) 438 return VM_PAGER_BAD; 439 440 bsize = vp->v_mount->mnt_stat.f_iosize; 441 442 VOP_BMAP(vp, 0, &dp, 0, NULL, NULL); 443 444 kva = vm_pager_map_page(m); 445 446 for (i = 0; i < PAGE_SIZE / bsize; i++) { 447 vm_ooffset_t address; 448 449 if (vm_page_bits(i * bsize, bsize) & m->valid) 450 continue; 451 452 address = IDX_TO_OFF(m->pindex) + i * bsize; 453 if (address >= object->un_pager.vnp.vnp_size) { 454 fileaddr = -1; 455 } else { 456 fileaddr = vnode_pager_addr(vp, address, NULL); 457 } 458 if (fileaddr != -1) { 459 bp = getpbuf(&vnode_pbuf_freecnt); 460 461 /* build a minimal buffer header */ 462 bp->b_iocmd = BIO_READ; 463 bp->b_iodone = vnode_pager_iodone; 464 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 465 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 466 bp->b_rcred = crhold(curthread->td_proc->p_ucred); 467 bp->b_wcred = crhold(curthread->td_proc->p_ucred); 468 bp->b_data = (caddr_t) kva + i * bsize; 469 bp->b_blkno = fileaddr; 470 pbgetvp(dp, bp); 471 bp->b_bcount = bsize; 472 bp->b_bufsize = bsize; 473 bp->b_runningbufspace = bp->b_bufsize; 474 runningbufspace += bp->b_runningbufspace; 475 476 /* do the input */ 477 BUF_STRATEGY(bp); 478 479 /* we definitely need to be at splvm here */ 480 481 s = splvm(); 482 while ((bp->b_flags & B_DONE) == 0) { 483 tsleep(bp, PVM, "vnsrd", 0); 484 } 485 splx(s); 486 if ((bp->b_ioflags & BIO_ERROR) != 0) 487 error = EIO; 488 489 /* 490 * free the buffer header back to the swap buffer pool 491 */ 492 relpbuf(bp, &vnode_pbuf_freecnt); 493 if (error) 494 break; 495 496 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 497 } else { 498 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 499 bzero((caddr_t) kva + i * bsize, bsize); 500 } 501 } 502 vm_pager_unmap_page(kva); 503 pmap_clear_modify(m); 504 vm_page_flag_clear(m, PG_ZERO); 505 if (error) { 506 return VM_PAGER_ERROR; 507 } 508 return VM_PAGER_OK; 509 510 } 511 512 513 /* 514 * old style vnode pager output routine 515 */ 516 static int 517 vnode_pager_input_old(object, m) 518 vm_object_t object; 519 vm_page_t m; 520 { 521 struct uio auio; 522 struct iovec aiov; 523 int error; 524 int size; 525 vm_offset_t kva; 526 struct vnode *vp; 527 528 GIANT_REQUIRED; 529 error = 0; 530 531 /* 532 * Return failure if beyond current EOF 533 */ 534 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 535 return VM_PAGER_BAD; 536 } else { 537 size = PAGE_SIZE; 538 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 539 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 540 541 /* 542 * Allocate a kernel virtual address and initialize so that 543 * we can use VOP_READ/WRITE routines. 544 */ 545 kva = vm_pager_map_page(m); 546 547 vp = object->handle; 548 aiov.iov_base = (caddr_t) kva; 549 aiov.iov_len = size; 550 auio.uio_iov = &aiov; 551 auio.uio_iovcnt = 1; 552 auio.uio_offset = IDX_TO_OFF(m->pindex); 553 auio.uio_segflg = UIO_SYSSPACE; 554 auio.uio_rw = UIO_READ; 555 auio.uio_resid = size; 556 auio.uio_td = curthread; 557 558 error = VOP_READ(vp, &auio, 0, curthread->td_proc->p_ucred); 559 if (!error) { 560 int count = size - auio.uio_resid; 561 562 if (count == 0) 563 error = EINVAL; 564 else if (count != PAGE_SIZE) 565 bzero((caddr_t) kva + count, PAGE_SIZE - count); 566 } 567 vm_pager_unmap_page(kva); 568 } 569 pmap_clear_modify(m); 570 vm_page_undirty(m); 571 vm_page_flag_clear(m, PG_ZERO); 572 if (!error) 573 m->valid = VM_PAGE_BITS_ALL; 574 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 575 } 576 577 /* 578 * generic vnode pager input routine 579 */ 580 581 /* 582 * Local media VFS's that do not implement their own VOP_GETPAGES 583 * should have their VOP_GETPAGES should call to 584 * vnode_pager_generic_getpages() to implement the previous behaviour. 585 * 586 * All other FS's should use the bypass to get to the local media 587 * backing vp's VOP_GETPAGES. 588 */ 589 static int 590 vnode_pager_getpages(object, m, count, reqpage) 591 vm_object_t object; 592 vm_page_t *m; 593 int count; 594 int reqpage; 595 { 596 int rtval; 597 struct vnode *vp; 598 int bytes = count * PAGE_SIZE; 599 600 GIANT_REQUIRED; 601 vp = object->handle; 602 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 603 KASSERT(rtval != EOPNOTSUPP, 604 ("vnode_pager: FS getpages not implemented\n")); 605 return rtval; 606 } 607 608 609 /* 610 * This is now called from local media FS's to operate against their 611 * own vnodes if they fail to implement VOP_GETPAGES. 612 */ 613 int 614 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 615 struct vnode *vp; 616 vm_page_t *m; 617 int bytecount; 618 int reqpage; 619 { 620 vm_object_t object; 621 vm_offset_t kva; 622 off_t foff, tfoff, nextoff; 623 int i, size, bsize, first, firstaddr; 624 struct vnode *dp; 625 int runpg; 626 int runend; 627 struct buf *bp; 628 int s; 629 int count; 630 int error = 0; 631 632 GIANT_REQUIRED; 633 object = vp->v_object; 634 count = bytecount / PAGE_SIZE; 635 636 if (vp->v_mount == NULL) 637 return VM_PAGER_BAD; 638 639 bsize = vp->v_mount->mnt_stat.f_iosize; 640 641 /* get the UNDERLYING device for the file with VOP_BMAP() */ 642 643 /* 644 * originally, we did not check for an error return value -- assuming 645 * an fs always has a bmap entry point -- that assumption is wrong!!! 646 */ 647 foff = IDX_TO_OFF(m[reqpage]->pindex); 648 649 /* 650 * if we can't bmap, use old VOP code 651 */ 652 if (VOP_BMAP(vp, 0, &dp, 0, NULL, NULL)) { 653 for (i = 0; i < count; i++) { 654 if (i != reqpage) { 655 vm_page_free(m[i]); 656 } 657 } 658 cnt.v_vnodein++; 659 cnt.v_vnodepgsin++; 660 return vnode_pager_input_old(object, m[reqpage]); 661 662 /* 663 * if the blocksize is smaller than a page size, then use 664 * special small filesystem code. NFS sometimes has a small 665 * blocksize, but it can handle large reads itself. 666 */ 667 } else if ((PAGE_SIZE / bsize) > 1 && 668 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 669 for (i = 0; i < count; i++) { 670 if (i != reqpage) { 671 vm_page_free(m[i]); 672 } 673 } 674 cnt.v_vnodein++; 675 cnt.v_vnodepgsin++; 676 return vnode_pager_input_smlfs(object, m[reqpage]); 677 } 678 679 /* 680 * If we have a completely valid page available to us, we can 681 * clean up and return. Otherwise we have to re-read the 682 * media. 683 */ 684 685 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 686 for (i = 0; i < count; i++) { 687 if (i != reqpage) 688 vm_page_free(m[i]); 689 } 690 return VM_PAGER_OK; 691 } 692 m[reqpage]->valid = 0; 693 694 /* 695 * here on direct device I/O 696 */ 697 698 firstaddr = -1; 699 /* 700 * calculate the run that includes the required page 701 */ 702 for(first = 0, i = 0; i < count; i = runend) { 703 firstaddr = vnode_pager_addr(vp, 704 IDX_TO_OFF(m[i]->pindex), &runpg); 705 if (firstaddr == -1) { 706 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 707 /* XXX no %qd in kernel. */ 708 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %d, foff: 0x%lx%08lx, vnp_size: 0x%lx%08lx", 709 firstaddr, (u_long)(foff >> 32), 710 (u_long)(u_int32_t)foff, 711 (u_long)(u_int32_t) 712 (object->un_pager.vnp.vnp_size >> 32), 713 (u_long)(u_int32_t) 714 object->un_pager.vnp.vnp_size); 715 } 716 vm_page_free(m[i]); 717 runend = i + 1; 718 first = runend; 719 continue; 720 } 721 runend = i + runpg; 722 if (runend <= reqpage) { 723 int j; 724 for (j = i; j < runend; j++) { 725 vm_page_free(m[j]); 726 } 727 } else { 728 if (runpg < (count - first)) { 729 for (i = first + runpg; i < count; i++) 730 vm_page_free(m[i]); 731 count = first + runpg; 732 } 733 break; 734 } 735 first = runend; 736 } 737 738 /* 739 * the first and last page have been calculated now, move input pages 740 * to be zero based... 741 */ 742 if (first != 0) { 743 for (i = first; i < count; i++) { 744 m[i - first] = m[i]; 745 } 746 count -= first; 747 reqpage -= first; 748 } 749 750 /* 751 * calculate the file virtual address for the transfer 752 */ 753 foff = IDX_TO_OFF(m[0]->pindex); 754 755 /* 756 * calculate the size of the transfer 757 */ 758 size = count * PAGE_SIZE; 759 if ((foff + size) > object->un_pager.vnp.vnp_size) 760 size = object->un_pager.vnp.vnp_size - foff; 761 762 /* 763 * round up physical size for real devices. 764 */ 765 if (dp->v_type == VBLK || dp->v_type == VCHR) { 766 int secmask = dp->v_rdev->si_bsize_phys - 1; 767 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 768 size = (size + secmask) & ~secmask; 769 } 770 771 bp = getpbuf(&vnode_pbuf_freecnt); 772 kva = (vm_offset_t) bp->b_data; 773 774 /* 775 * and map the pages to be read into the kva 776 */ 777 pmap_qenter(kva, m, count); 778 779 /* build a minimal buffer header */ 780 bp->b_iocmd = BIO_READ; 781 bp->b_iodone = vnode_pager_iodone; 782 /* B_PHYS is not set, but it is nice to fill this in */ 783 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 784 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 785 bp->b_rcred = crhold(curthread->td_proc->p_ucred); 786 bp->b_wcred = crhold(curthread->td_proc->p_ucred); 787 bp->b_blkno = firstaddr; 788 pbgetvp(dp, bp); 789 bp->b_bcount = size; 790 bp->b_bufsize = size; 791 bp->b_runningbufspace = bp->b_bufsize; 792 runningbufspace += bp->b_runningbufspace; 793 794 cnt.v_vnodein++; 795 cnt.v_vnodepgsin += count; 796 797 /* do the input */ 798 BUF_STRATEGY(bp); 799 800 s = splvm(); 801 /* we definitely need to be at splvm here */ 802 803 while ((bp->b_flags & B_DONE) == 0) { 804 tsleep(bp, PVM, "vnread", 0); 805 } 806 splx(s); 807 if ((bp->b_ioflags & BIO_ERROR) != 0) 808 error = EIO; 809 810 if (!error) { 811 if (size != count * PAGE_SIZE) 812 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 813 } 814 pmap_qremove(kva, count); 815 816 /* 817 * free the buffer header back to the swap buffer pool 818 */ 819 relpbuf(bp, &vnode_pbuf_freecnt); 820 821 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 822 vm_page_t mt; 823 824 nextoff = tfoff + PAGE_SIZE; 825 mt = m[i]; 826 827 if (nextoff <= object->un_pager.vnp.vnp_size) { 828 /* 829 * Read filled up entire page. 830 */ 831 mt->valid = VM_PAGE_BITS_ALL; 832 vm_page_undirty(mt); /* should be an assert? XXX */ 833 pmap_clear_modify(mt); 834 } else { 835 /* 836 * Read did not fill up entire page. Since this 837 * is getpages, the page may be mapped, so we have 838 * to zero the invalid portions of the page even 839 * though we aren't setting them valid. 840 * 841 * Currently we do not set the entire page valid, 842 * we just try to clear the piece that we couldn't 843 * read. 844 */ 845 vm_page_set_validclean(mt, 0, 846 object->un_pager.vnp.vnp_size - tfoff); 847 /* handled by vm_fault now */ 848 /* vm_page_zero_invalid(mt, FALSE); */ 849 } 850 851 vm_page_flag_clear(mt, PG_ZERO); 852 if (i != reqpage) { 853 854 /* 855 * whether or not to leave the page activated is up in 856 * the air, but we should put the page on a page queue 857 * somewhere. (it already is in the object). Result: 858 * It appears that empirical results show that 859 * deactivating pages is best. 860 */ 861 862 /* 863 * just in case someone was asking for this page we 864 * now tell them that it is ok to use 865 */ 866 if (!error) { 867 if (mt->flags & PG_WANTED) 868 vm_page_activate(mt); 869 else 870 vm_page_deactivate(mt); 871 vm_page_wakeup(mt); 872 } else { 873 vm_page_free(mt); 874 } 875 } 876 } 877 if (error) { 878 printf("vnode_pager_getpages: I/O read error\n"); 879 } 880 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 881 } 882 883 /* 884 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 885 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 886 * vnode_pager_generic_putpages() to implement the previous behaviour. 887 * 888 * All other FS's should use the bypass to get to the local media 889 * backing vp's VOP_PUTPAGES. 890 */ 891 static void 892 vnode_pager_putpages(object, m, count, sync, rtvals) 893 vm_object_t object; 894 vm_page_t *m; 895 int count; 896 boolean_t sync; 897 int *rtvals; 898 { 899 int rtval; 900 struct vnode *vp; 901 struct mount *mp; 902 int bytes = count * PAGE_SIZE; 903 904 GIANT_REQUIRED; 905 /* 906 * Force synchronous operation if we are extremely low on memory 907 * to prevent a low-memory deadlock. VOP operations often need to 908 * allocate more memory to initiate the I/O ( i.e. do a BMAP 909 * operation ). The swapper handles the case by limiting the amount 910 * of asynchronous I/O, but that sort of solution doesn't scale well 911 * for the vnode pager without a lot of work. 912 * 913 * Also, the backing vnode's iodone routine may not wake the pageout 914 * daemon up. This should be probably be addressed XXX. 915 */ 916 917 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 918 sync |= OBJPC_SYNC; 919 920 /* 921 * Call device-specific putpages function 922 */ 923 924 vp = object->handle; 925 if (vp->v_type != VREG) 926 mp = NULL; 927 (void)vn_start_write(vp, &mp, V_WAIT); 928 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 929 KASSERT(rtval != EOPNOTSUPP, 930 ("vnode_pager: stale FS putpages\n")); 931 vn_finished_write(mp); 932 } 933 934 935 /* 936 * This is now called from local media FS's to operate against their 937 * own vnodes if they fail to implement VOP_PUTPAGES. 938 * 939 * This is typically called indirectly via the pageout daemon and 940 * clustering has already typically occured, so in general we ask the 941 * underlying filesystem to write the data out asynchronously rather 942 * then delayed. 943 */ 944 int 945 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) 946 struct vnode *vp; 947 vm_page_t *m; 948 int bytecount; 949 int flags; 950 int *rtvals; 951 { 952 int i; 953 vm_object_t object; 954 int count; 955 956 int maxsize, ncount; 957 vm_ooffset_t poffset; 958 struct uio auio; 959 struct iovec aiov; 960 int error; 961 int ioflags; 962 963 GIANT_REQUIRED; 964 object = vp->v_object; 965 count = bytecount / PAGE_SIZE; 966 967 for (i = 0; i < count; i++) 968 rtvals[i] = VM_PAGER_AGAIN; 969 970 if ((int) m[0]->pindex < 0) { 971 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 972 (long)m[0]->pindex, m[0]->dirty); 973 rtvals[0] = VM_PAGER_BAD; 974 return VM_PAGER_BAD; 975 } 976 977 maxsize = count * PAGE_SIZE; 978 ncount = count; 979 980 poffset = IDX_TO_OFF(m[0]->pindex); 981 982 /* 983 * If the page-aligned write is larger then the actual file we 984 * have to invalidate pages occuring beyond the file EOF. However, 985 * there is an edge case where a file may not be page-aligned where 986 * the last page is partially invalid. In this case the filesystem 987 * may not properly clear the dirty bits for the entire page (which 988 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 989 * With the page locked we are free to fix-up the dirty bits here. 990 * 991 * We do not under any circumstances truncate the valid bits, as 992 * this will screw up bogus page replacement. 993 */ 994 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 995 if (object->un_pager.vnp.vnp_size > poffset) { 996 int pgoff; 997 998 maxsize = object->un_pager.vnp.vnp_size - poffset; 999 ncount = btoc(maxsize); 1000 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1001 vm_page_clear_dirty(m[ncount - 1], pgoff, 1002 PAGE_SIZE - pgoff); 1003 } 1004 } else { 1005 maxsize = 0; 1006 ncount = 0; 1007 } 1008 if (ncount < count) { 1009 for (i = ncount; i < count; i++) { 1010 rtvals[i] = VM_PAGER_BAD; 1011 } 1012 } 1013 } 1014 1015 /* 1016 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1017 * rather then a bdwrite() to prevent paging I/O from saturating 1018 * the buffer cache. 1019 */ 1020 ioflags = IO_VMIO; 1021 ioflags |= (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) ? IO_SYNC: IO_ASYNC; 1022 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1023 1024 aiov.iov_base = (caddr_t) 0; 1025 aiov.iov_len = maxsize; 1026 auio.uio_iov = &aiov; 1027 auio.uio_iovcnt = 1; 1028 auio.uio_offset = poffset; 1029 auio.uio_segflg = UIO_NOCOPY; 1030 auio.uio_rw = UIO_WRITE; 1031 auio.uio_resid = maxsize; 1032 auio.uio_td = (struct thread *) 0; 1033 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_proc->p_ucred); 1034 cnt.v_vnodeout++; 1035 cnt.v_vnodepgsout += ncount; 1036 1037 if (error) { 1038 printf("vnode_pager_putpages: I/O error %d\n", error); 1039 } 1040 if (auio.uio_resid) { 1041 printf("vnode_pager_putpages: residual I/O %d at %lu\n", 1042 auio.uio_resid, (u_long)m[0]->pindex); 1043 } 1044 for (i = 0; i < ncount; i++) { 1045 rtvals[i] = VM_PAGER_OK; 1046 } 1047 return rtvals[0]; 1048 } 1049 1050 struct vnode * 1051 vnode_pager_lock(object) 1052 vm_object_t object; 1053 { 1054 struct thread *td = curthread; /* XXX */ 1055 1056 GIANT_REQUIRED; 1057 1058 for (; object != NULL; object = object->backing_object) { 1059 if (object->type != OBJT_VNODE) 1060 continue; 1061 if (object->flags & OBJ_DEAD) { 1062 return NULL; 1063 } 1064 1065 /* XXX; If object->handle can change, we need to cache it. */ 1066 while (vget(object->handle, 1067 LK_NOPAUSE | LK_SHARED | LK_RETRY | LK_CANRECURSE, td)){ 1068 if ((object->flags & OBJ_DEAD) || (object->type != OBJT_VNODE)) 1069 return NULL; 1070 printf("vnode_pager_lock: retrying\n"); 1071 } 1072 return object->handle; 1073 } 1074 return NULL; 1075 } 1076