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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/5.2/sys/vm/vnode_pager.c 122748 2003-11-15 09:54:11Z tjr $"); 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/conf.h> 65 66 #include <vm/vm.h> 67 #include <vm/vm_object.h> 68 #include <vm/vm_page.h> 69 #include <vm/vm_pager.h> 70 #include <vm/vm_map.h> 71 #include <vm/vnode_pager.h> 72 #include <vm/vm_extern.h> 73 74 static void vnode_pager_init(void); 75 static vm_offset_t vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 76 int *run); 77 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 78 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 79 static void vnode_pager_dealloc(vm_object_t); 80 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 81 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); 82 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 83 84 struct pagerops vnodepagerops = { 85 .pgo_init = vnode_pager_init, 86 .pgo_alloc = vnode_pager_alloc, 87 .pgo_dealloc = vnode_pager_dealloc, 88 .pgo_getpages = vnode_pager_getpages, 89 .pgo_putpages = vnode_pager_putpages, 90 .pgo_haspage = vnode_pager_haspage, 91 }; 92 93 int vnode_pbuf_freecnt; 94 95 static 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 * MPSAFE 107 */ 108 vm_object_t 109 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 110 vm_ooffset_t offset) 111 { 112 vm_object_t object; 113 struct vnode *vp; 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 ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc"); 124 125 mtx_lock(&Giant); 126 /* 127 * Prevent race condition when allocating the object. This 128 * can happen with NFS vnodes since the nfsnode isn't locked. 129 */ 130 VI_LOCK(vp); 131 while (vp->v_iflag & VI_OLOCK) { 132 vp->v_iflag |= VI_OWANT; 133 msleep(vp, VI_MTX(vp), PVM, "vnpobj", 0); 134 } 135 vp->v_iflag |= VI_OLOCK; 136 VI_UNLOCK(vp); 137 138 /* 139 * If the object is being terminated, wait for it to 140 * go away. 141 */ 142 while ((object = vp->v_object) != NULL) { 143 VM_OBJECT_LOCK(object); 144 if ((object->flags & OBJ_DEAD) == 0) 145 break; 146 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); 147 } 148 149 if (vp->v_usecount == 0) 150 panic("vnode_pager_alloc: no vnode reference"); 151 152 if (object == NULL) { 153 /* 154 * And an object of the appropriate size 155 */ 156 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 157 158 object->un_pager.vnp.vnp_size = size; 159 160 object->handle = handle; 161 vp->v_object = object; 162 } else { 163 object->ref_count++; 164 VM_OBJECT_UNLOCK(object); 165 } 166 VI_LOCK(vp); 167 vp->v_usecount++; 168 vp->v_iflag &= ~VI_OLOCK; 169 if (vp->v_iflag & VI_OWANT) { 170 vp->v_iflag &= ~VI_OWANT; 171 wakeup(vp); 172 } 173 VI_UNLOCK(vp); 174 mtx_unlock(&Giant); 175 return (object); 176 } 177 178 /* 179 * The object must be locked. 180 */ 181 static void 182 vnode_pager_dealloc(object) 183 vm_object_t object; 184 { 185 struct vnode *vp = object->handle; 186 187 if (vp == NULL) 188 panic("vnode_pager_dealloc: pager already dealloced"); 189 190 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 191 vm_object_pip_wait(object, "vnpdea"); 192 193 object->handle = NULL; 194 object->type = OBJT_DEAD; 195 ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc"); 196 vp->v_object = NULL; 197 vp->v_vflag &= ~(VV_TEXT | VV_OBJBUF); 198 } 199 200 static boolean_t 201 vnode_pager_haspage(object, pindex, before, after) 202 vm_object_t object; 203 vm_pindex_t pindex; 204 int *before; 205 int *after; 206 { 207 struct vnode *vp = object->handle; 208 daddr_t bn; 209 int err; 210 daddr_t reqblock; 211 int poff; 212 int bsize; 213 int pagesperblock, blocksperpage; 214 215 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 216 /* 217 * If no vp or vp is doomed or marked transparent to VM, we do not 218 * have the page. 219 */ 220 if (vp == NULL) 221 return FALSE; 222 223 VI_LOCK(vp); 224 if (vp->v_iflag & VI_DOOMED) { 225 VI_UNLOCK(vp); 226 return FALSE; 227 } 228 VI_UNLOCK(vp); 229 /* 230 * If filesystem no longer mounted or offset beyond end of file we do 231 * not have the page. 232 */ 233 if ((vp->v_mount == NULL) || 234 (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)) 235 return FALSE; 236 237 bsize = vp->v_mount->mnt_stat.f_iosize; 238 pagesperblock = bsize / PAGE_SIZE; 239 blocksperpage = 0; 240 if (pagesperblock > 0) { 241 reqblock = pindex / pagesperblock; 242 } else { 243 blocksperpage = (PAGE_SIZE / bsize); 244 reqblock = pindex * blocksperpage; 245 } 246 VM_OBJECT_UNLOCK(object); 247 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 248 VM_OBJECT_LOCK(object); 249 if (err) 250 return TRUE; 251 if (bn == -1) 252 return FALSE; 253 if (pagesperblock > 0) { 254 poff = pindex - (reqblock * pagesperblock); 255 if (before) { 256 *before *= pagesperblock; 257 *before += poff; 258 } 259 if (after) { 260 int numafter; 261 *after *= pagesperblock; 262 numafter = pagesperblock - (poff + 1); 263 if (IDX_TO_OFF(pindex + numafter) > 264 object->un_pager.vnp.vnp_size) { 265 numafter = 266 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 267 pindex; 268 } 269 *after += numafter; 270 } 271 } else { 272 if (before) { 273 *before /= blocksperpage; 274 } 275 276 if (after) { 277 *after /= blocksperpage; 278 } 279 } 280 return TRUE; 281 } 282 283 /* 284 * Lets the VM system know about a change in size for a file. 285 * We adjust our own internal size and flush any cached pages in 286 * the associated object that are affected by the size change. 287 * 288 * Note: this routine may be invoked as a result of a pager put 289 * operation (possibly at object termination time), so we must be careful. 290 */ 291 void 292 vnode_pager_setsize(vp, nsize) 293 struct vnode *vp; 294 vm_ooffset_t nsize; 295 { 296 vm_object_t object; 297 vm_page_t m; 298 vm_pindex_t nobjsize; 299 300 if ((object = vp->v_object) == NULL) 301 return; 302 VM_OBJECT_LOCK(object); 303 if (nsize == object->un_pager.vnp.vnp_size) { 304 /* 305 * Hasn't changed size 306 */ 307 VM_OBJECT_UNLOCK(object); 308 return; 309 } 310 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 311 if (nsize < object->un_pager.vnp.vnp_size) { 312 /* 313 * File has shrunk. Toss any cached pages beyond the new EOF. 314 */ 315 if (nobjsize < object->size) 316 vm_object_page_remove(object, nobjsize, object->size, 317 FALSE); 318 /* 319 * this gets rid of garbage at the end of a page that is now 320 * only partially backed by the vnode. 321 * 322 * XXX for some reason (I don't know yet), if we take a 323 * completely invalid page and mark it partially valid 324 * it can screw up NFS reads, so we don't allow the case. 325 */ 326 if ((nsize & PAGE_MASK) && 327 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 328 m->valid != 0) { 329 int base = (int)nsize & PAGE_MASK; 330 int size = PAGE_SIZE - base; 331 332 /* 333 * Clear out partial-page garbage in case 334 * the page has been mapped. 335 */ 336 pmap_zero_page_area(m, base, size); 337 338 /* 339 * XXX work around SMP data integrity race 340 * by unmapping the page from user processes. 341 * The garbage we just cleared may be mapped 342 * to a user process running on another cpu 343 * and this code is not running through normal 344 * I/O channels which handle SMP issues for 345 * us, so unmap page to synchronize all cpus. 346 * 347 * XXX should vm_pager_unmap_page() have 348 * dealt with this? 349 */ 350 vm_page_lock_queues(); 351 pmap_remove_all(m); 352 353 /* 354 * Clear out partial-page dirty bits. This 355 * has the side effect of setting the valid 356 * bits, but that is ok. There are a bunch 357 * of places in the VM system where we expected 358 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 359 * case is one of them. If the page is still 360 * partially dirty, make it fully dirty. 361 * 362 * note that we do not clear out the valid 363 * bits. This would prevent bogus_page 364 * replacement from working properly. 365 */ 366 vm_page_set_validclean(m, base, size); 367 if (m->dirty != 0) 368 m->dirty = VM_PAGE_BITS_ALL; 369 vm_page_unlock_queues(); 370 } 371 } 372 object->un_pager.vnp.vnp_size = nsize; 373 object->size = nobjsize; 374 VM_OBJECT_UNLOCK(object); 375 } 376 377 /* 378 * calculate the linear (byte) disk address of specified virtual 379 * file address 380 */ 381 static vm_offset_t 382 vnode_pager_addr(vp, address, run) 383 struct vnode *vp; 384 vm_ooffset_t address; 385 int *run; 386 { 387 int rtaddress; 388 int bsize; 389 daddr_t block; 390 int err; 391 daddr_t vblock; 392 int voffset; 393 394 GIANT_REQUIRED; 395 if ((int) address < 0) 396 return -1; 397 398 if (vp->v_mount == NULL) 399 return -1; 400 401 bsize = vp->v_mount->mnt_stat.f_iosize; 402 vblock = address / bsize; 403 voffset = address % bsize; 404 405 err = VOP_BMAP(vp, vblock, NULL, &block, run, NULL); 406 407 if (err || (block == -1)) 408 rtaddress = -1; 409 else { 410 rtaddress = block + voffset / DEV_BSIZE; 411 if (run) { 412 *run += 1; 413 *run *= bsize/PAGE_SIZE; 414 *run -= voffset/PAGE_SIZE; 415 } 416 } 417 418 return rtaddress; 419 } 420 421 /* 422 * small block filesystem vnode pager input 423 */ 424 static int 425 vnode_pager_input_smlfs(object, m) 426 vm_object_t object; 427 vm_page_t m; 428 { 429 int i; 430 struct vnode *dp, *vp; 431 struct buf *bp; 432 vm_offset_t kva; 433 int fileaddr; 434 vm_offset_t bsize; 435 int error = 0; 436 437 GIANT_REQUIRED; 438 439 vp = object->handle; 440 if (vp->v_mount == NULL) 441 return VM_PAGER_BAD; 442 443 bsize = vp->v_mount->mnt_stat.f_iosize; 444 445 VOP_BMAP(vp, 0, &dp, 0, NULL, NULL); 446 447 kva = vm_pager_map_page(m); 448 449 for (i = 0; i < PAGE_SIZE / bsize; i++) { 450 vm_ooffset_t address; 451 452 if (vm_page_bits(i * bsize, bsize) & m->valid) 453 continue; 454 455 address = IDX_TO_OFF(m->pindex) + i * bsize; 456 if (address >= object->un_pager.vnp.vnp_size) { 457 fileaddr = -1; 458 } else { 459 fileaddr = vnode_pager_addr(vp, address, NULL); 460 } 461 if (fileaddr != -1) { 462 bp = getpbuf(&vnode_pbuf_freecnt); 463 464 /* build a minimal buffer header */ 465 bp->b_iocmd = BIO_READ; 466 bp->b_iodone = bdone; 467 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 468 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 469 bp->b_rcred = crhold(curthread->td_ucred); 470 bp->b_wcred = crhold(curthread->td_ucred); 471 bp->b_data = (caddr_t) kva + i * bsize; 472 bp->b_blkno = fileaddr; 473 pbgetvp(dp, bp); 474 bp->b_bcount = bsize; 475 bp->b_bufsize = bsize; 476 bp->b_runningbufspace = bp->b_bufsize; 477 runningbufspace += bp->b_runningbufspace; 478 479 /* do the input */ 480 bp->b_iooffset = dbtob(bp->b_blkno); 481 if (dp->v_type == VCHR) 482 VOP_SPECSTRATEGY(bp->b_vp, bp); 483 else 484 VOP_STRATEGY(bp->b_vp, bp); 485 486 /* we definitely need to be at splvm here */ 487 488 bwait(bp, PVM, "vnsrd"); 489 490 if ((bp->b_ioflags & BIO_ERROR) != 0) 491 error = EIO; 492 493 /* 494 * free the buffer header back to the swap buffer pool 495 */ 496 relpbuf(bp, &vnode_pbuf_freecnt); 497 if (error) 498 break; 499 500 VM_OBJECT_LOCK(object); 501 vm_page_lock_queues(); 502 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 503 vm_page_unlock_queues(); 504 VM_OBJECT_UNLOCK(object); 505 } else { 506 VM_OBJECT_LOCK(object); 507 vm_page_lock_queues(); 508 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 509 vm_page_unlock_queues(); 510 VM_OBJECT_UNLOCK(object); 511 bzero((caddr_t) kva + i * bsize, bsize); 512 } 513 } 514 vm_pager_unmap_page(kva); 515 vm_page_lock_queues(); 516 pmap_clear_modify(m); 517 vm_page_flag_clear(m, PG_ZERO); 518 vm_page_unlock_queues(); 519 if (error) { 520 return VM_PAGER_ERROR; 521 } 522 return VM_PAGER_OK; 523 524 } 525 526 527 /* 528 * old style vnode pager output routine 529 */ 530 static int 531 vnode_pager_input_old(object, m) 532 vm_object_t object; 533 vm_page_t m; 534 { 535 struct uio auio; 536 struct iovec aiov; 537 int error; 538 int size; 539 vm_offset_t kva; 540 struct vnode *vp; 541 542 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 543 error = 0; 544 545 /* 546 * Return failure if beyond current EOF 547 */ 548 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 549 return VM_PAGER_BAD; 550 } else { 551 size = PAGE_SIZE; 552 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 553 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 554 vp = object->handle; 555 VM_OBJECT_UNLOCK(object); 556 557 /* 558 * Allocate a kernel virtual address and initialize so that 559 * we can use VOP_READ/WRITE routines. 560 */ 561 kva = vm_pager_map_page(m); 562 563 aiov.iov_base = (caddr_t) kva; 564 aiov.iov_len = size; 565 auio.uio_iov = &aiov; 566 auio.uio_iovcnt = 1; 567 auio.uio_offset = IDX_TO_OFF(m->pindex); 568 auio.uio_segflg = UIO_SYSSPACE; 569 auio.uio_rw = UIO_READ; 570 auio.uio_resid = size; 571 auio.uio_td = curthread; 572 573 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 574 if (!error) { 575 int count = size - auio.uio_resid; 576 577 if (count == 0) 578 error = EINVAL; 579 else if (count != PAGE_SIZE) 580 bzero((caddr_t) kva + count, PAGE_SIZE - count); 581 } 582 vm_pager_unmap_page(kva); 583 584 VM_OBJECT_LOCK(object); 585 } 586 vm_page_lock_queues(); 587 pmap_clear_modify(m); 588 vm_page_undirty(m); 589 vm_page_flag_clear(m, PG_ZERO); 590 vm_page_unlock_queues(); 591 if (!error) 592 m->valid = VM_PAGE_BITS_ALL; 593 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 594 } 595 596 /* 597 * generic vnode pager input routine 598 */ 599 600 /* 601 * Local media VFS's that do not implement their own VOP_GETPAGES 602 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 603 * to implement the previous behaviour. 604 * 605 * All other FS's should use the bypass to get to the local media 606 * backing vp's VOP_GETPAGES. 607 */ 608 static int 609 vnode_pager_getpages(object, m, count, reqpage) 610 vm_object_t object; 611 vm_page_t *m; 612 int count; 613 int reqpage; 614 { 615 int rtval; 616 struct vnode *vp; 617 int bytes = count * PAGE_SIZE; 618 619 vp = object->handle; 620 VM_OBJECT_UNLOCK(object); 621 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 622 KASSERT(rtval != EOPNOTSUPP, 623 ("vnode_pager: FS getpages not implemented\n")); 624 VM_OBJECT_LOCK(object); 625 return rtval; 626 } 627 628 /* 629 * This is now called from local media FS's to operate against their 630 * own vnodes if they fail to implement VOP_GETPAGES. 631 */ 632 int 633 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 634 struct vnode *vp; 635 vm_page_t *m; 636 int bytecount; 637 int reqpage; 638 { 639 vm_object_t object; 640 vm_offset_t kva; 641 off_t foff, tfoff, nextoff; 642 int i, j, size, bsize, first, firstaddr; 643 struct vnode *dp; 644 int runpg; 645 int runend; 646 struct buf *bp; 647 int count; 648 int error = 0; 649 650 GIANT_REQUIRED; 651 object = vp->v_object; 652 count = bytecount / PAGE_SIZE; 653 654 if (vp->v_mount == NULL) 655 return VM_PAGER_BAD; 656 657 bsize = vp->v_mount->mnt_stat.f_iosize; 658 659 /* get the UNDERLYING device for the file with VOP_BMAP() */ 660 661 /* 662 * originally, we did not check for an error return value -- assuming 663 * an fs always has a bmap entry point -- that assumption is wrong!!! 664 */ 665 foff = IDX_TO_OFF(m[reqpage]->pindex); 666 667 /* 668 * if we can't bmap, use old VOP code 669 */ 670 if (VOP_BMAP(vp, 0, &dp, 0, NULL, NULL)) { 671 VM_OBJECT_LOCK(object); 672 vm_page_lock_queues(); 673 for (i = 0; i < count; i++) 674 if (i != reqpage) 675 vm_page_free(m[i]); 676 vm_page_unlock_queues(); 677 cnt.v_vnodein++; 678 cnt.v_vnodepgsin++; 679 error = vnode_pager_input_old(object, m[reqpage]); 680 VM_OBJECT_UNLOCK(object); 681 return (error); 682 683 /* 684 * if the blocksize is smaller than a page size, then use 685 * special small filesystem code. NFS sometimes has a small 686 * blocksize, but it can handle large reads itself. 687 */ 688 } else if ((PAGE_SIZE / bsize) > 1 && 689 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 690 VM_OBJECT_LOCK(object); 691 vm_page_lock_queues(); 692 for (i = 0; i < count; i++) 693 if (i != reqpage) 694 vm_page_free(m[i]); 695 vm_page_unlock_queues(); 696 VM_OBJECT_UNLOCK(object); 697 cnt.v_vnodein++; 698 cnt.v_vnodepgsin++; 699 return vnode_pager_input_smlfs(object, m[reqpage]); 700 } 701 702 /* 703 * If we have a completely valid page available to us, we can 704 * clean up and return. Otherwise we have to re-read the 705 * media. 706 */ 707 VM_OBJECT_LOCK(object); 708 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 709 vm_page_lock_queues(); 710 for (i = 0; i < count; i++) 711 if (i != reqpage) 712 vm_page_free(m[i]); 713 vm_page_unlock_queues(); 714 VM_OBJECT_UNLOCK(object); 715 return VM_PAGER_OK; 716 } 717 m[reqpage]->valid = 0; 718 VM_OBJECT_UNLOCK(object); 719 720 /* 721 * here on direct device I/O 722 */ 723 firstaddr = -1; 724 725 /* 726 * calculate the run that includes the required page 727 */ 728 for (first = 0, i = 0; i < count; i = runend) { 729 firstaddr = vnode_pager_addr(vp, 730 IDX_TO_OFF(m[i]->pindex), &runpg); 731 if (firstaddr == -1) { 732 VM_OBJECT_LOCK(object); 733 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 734 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %d, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 735 firstaddr, (uintmax_t)(foff >> 32), 736 (uintmax_t)foff, 737 (uintmax_t) 738 (object->un_pager.vnp.vnp_size >> 32), 739 (uintmax_t)object->un_pager.vnp.vnp_size); 740 } 741 vm_page_lock_queues(); 742 vm_page_free(m[i]); 743 vm_page_unlock_queues(); 744 VM_OBJECT_UNLOCK(object); 745 runend = i + 1; 746 first = runend; 747 continue; 748 } 749 runend = i + runpg; 750 if (runend <= reqpage) { 751 VM_OBJECT_LOCK(object); 752 vm_page_lock_queues(); 753 for (j = i; j < runend; j++) 754 vm_page_free(m[j]); 755 vm_page_unlock_queues(); 756 VM_OBJECT_UNLOCK(object); 757 } else { 758 if (runpg < (count - first)) { 759 VM_OBJECT_LOCK(object); 760 vm_page_lock_queues(); 761 for (i = first + runpg; i < count; i++) 762 vm_page_free(m[i]); 763 vm_page_unlock_queues(); 764 VM_OBJECT_UNLOCK(object); 765 count = first + runpg; 766 } 767 break; 768 } 769 first = runend; 770 } 771 772 /* 773 * the first and last page have been calculated now, move input pages 774 * to be zero based... 775 */ 776 if (first != 0) { 777 for (i = first; i < count; i++) { 778 m[i - first] = m[i]; 779 } 780 count -= first; 781 reqpage -= first; 782 } 783 784 /* 785 * calculate the file virtual address for the transfer 786 */ 787 foff = IDX_TO_OFF(m[0]->pindex); 788 789 /* 790 * calculate the size of the transfer 791 */ 792 size = count * PAGE_SIZE; 793 if ((foff + size) > object->un_pager.vnp.vnp_size) 794 size = object->un_pager.vnp.vnp_size - foff; 795 796 /* 797 * round up physical size for real devices. 798 */ 799 if (dp->v_type == VBLK || dp->v_type == VCHR) { 800 int secmask = dp->v_rdev->si_bsize_phys - 1; 801 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 802 size = (size + secmask) & ~secmask; 803 } 804 805 bp = getpbuf(&vnode_pbuf_freecnt); 806 kva = (vm_offset_t) bp->b_data; 807 808 /* 809 * and map the pages to be read into the kva 810 */ 811 pmap_qenter(kva, m, count); 812 813 /* build a minimal buffer header */ 814 bp->b_iocmd = BIO_READ; 815 bp->b_iodone = bdone; 816 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 817 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 818 bp->b_rcred = crhold(curthread->td_ucred); 819 bp->b_wcred = crhold(curthread->td_ucred); 820 bp->b_blkno = firstaddr; 821 pbgetvp(dp, bp); 822 bp->b_bcount = size; 823 bp->b_bufsize = size; 824 bp->b_runningbufspace = bp->b_bufsize; 825 runningbufspace += bp->b_runningbufspace; 826 827 cnt.v_vnodein++; 828 cnt.v_vnodepgsin += count; 829 830 /* do the input */ 831 bp->b_iooffset = dbtob(bp->b_blkno); 832 if (dp->v_type == VCHR) 833 VOP_SPECSTRATEGY(bp->b_vp, bp); 834 else 835 VOP_STRATEGY(bp->b_vp, bp); 836 837 bwait(bp, PVM, "vnread"); 838 839 if ((bp->b_ioflags & BIO_ERROR) != 0) 840 error = EIO; 841 842 if (!error) { 843 if (size != count * PAGE_SIZE) 844 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 845 } 846 pmap_qremove(kva, count); 847 848 /* 849 * free the buffer header back to the swap buffer pool 850 */ 851 relpbuf(bp, &vnode_pbuf_freecnt); 852 853 VM_OBJECT_LOCK(object); 854 vm_page_lock_queues(); 855 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 856 vm_page_t mt; 857 858 nextoff = tfoff + PAGE_SIZE; 859 mt = m[i]; 860 861 if (nextoff <= object->un_pager.vnp.vnp_size) { 862 /* 863 * Read filled up entire page. 864 */ 865 mt->valid = VM_PAGE_BITS_ALL; 866 vm_page_undirty(mt); /* should be an assert? XXX */ 867 pmap_clear_modify(mt); 868 } else { 869 /* 870 * Read did not fill up entire page. Since this 871 * is getpages, the page may be mapped, so we have 872 * to zero the invalid portions of the page even 873 * though we aren't setting them valid. 874 * 875 * Currently we do not set the entire page valid, 876 * we just try to clear the piece that we couldn't 877 * read. 878 */ 879 vm_page_set_validclean(mt, 0, 880 object->un_pager.vnp.vnp_size - tfoff); 881 /* handled by vm_fault now */ 882 /* vm_page_zero_invalid(mt, FALSE); */ 883 } 884 885 vm_page_flag_clear(mt, PG_ZERO); 886 if (i != reqpage) { 887 888 /* 889 * whether or not to leave the page activated is up in 890 * the air, but we should put the page on a page queue 891 * somewhere. (it already is in the object). Result: 892 * It appears that empirical results show that 893 * deactivating pages is best. 894 */ 895 896 /* 897 * just in case someone was asking for this page we 898 * now tell them that it is ok to use 899 */ 900 if (!error) { 901 if (mt->flags & PG_WANTED) 902 vm_page_activate(mt); 903 else 904 vm_page_deactivate(mt); 905 vm_page_wakeup(mt); 906 } else { 907 vm_page_free(mt); 908 } 909 } 910 } 911 vm_page_unlock_queues(); 912 VM_OBJECT_UNLOCK(object); 913 if (error) { 914 printf("vnode_pager_getpages: I/O read error\n"); 915 } 916 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 917 } 918 919 /* 920 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 921 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 922 * vnode_pager_generic_putpages() to implement the previous behaviour. 923 * 924 * All other FS's should use the bypass to get to the local media 925 * backing vp's VOP_PUTPAGES. 926 */ 927 static void 928 vnode_pager_putpages(object, m, count, sync, rtvals) 929 vm_object_t object; 930 vm_page_t *m; 931 int count; 932 boolean_t sync; 933 int *rtvals; 934 { 935 int rtval; 936 struct vnode *vp; 937 struct mount *mp; 938 int bytes = count * PAGE_SIZE; 939 940 GIANT_REQUIRED; 941 /* 942 * Force synchronous operation if we are extremely low on memory 943 * to prevent a low-memory deadlock. VOP operations often need to 944 * allocate more memory to initiate the I/O ( i.e. do a BMAP 945 * operation ). The swapper handles the case by limiting the amount 946 * of asynchronous I/O, but that sort of solution doesn't scale well 947 * for the vnode pager without a lot of work. 948 * 949 * Also, the backing vnode's iodone routine may not wake the pageout 950 * daemon up. This should be probably be addressed XXX. 951 */ 952 953 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 954 sync |= OBJPC_SYNC; 955 956 /* 957 * Call device-specific putpages function 958 */ 959 vp = object->handle; 960 VM_OBJECT_UNLOCK(object); 961 if (vp->v_type != VREG) 962 mp = NULL; 963 (void)vn_start_write(vp, &mp, V_WAIT); 964 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 965 KASSERT(rtval != EOPNOTSUPP, 966 ("vnode_pager: stale FS putpages\n")); 967 vn_finished_write(mp); 968 VM_OBJECT_LOCK(object); 969 } 970 971 972 /* 973 * This is now called from local media FS's to operate against their 974 * own vnodes if they fail to implement VOP_PUTPAGES. 975 * 976 * This is typically called indirectly via the pageout daemon and 977 * clustering has already typically occured, so in general we ask the 978 * underlying filesystem to write the data out asynchronously rather 979 * then delayed. 980 */ 981 int 982 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) 983 struct vnode *vp; 984 vm_page_t *m; 985 int bytecount; 986 int flags; 987 int *rtvals; 988 { 989 int i; 990 vm_object_t object; 991 int count; 992 993 int maxsize, ncount; 994 vm_ooffset_t poffset; 995 struct uio auio; 996 struct iovec aiov; 997 int error; 998 int ioflags; 999 1000 GIANT_REQUIRED; 1001 object = vp->v_object; 1002 count = bytecount / PAGE_SIZE; 1003 1004 for (i = 0; i < count; i++) 1005 rtvals[i] = VM_PAGER_AGAIN; 1006 1007 if ((int) m[0]->pindex < 0) { 1008 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1009 (long)m[0]->pindex, (u_long)m[0]->dirty); 1010 rtvals[0] = VM_PAGER_BAD; 1011 return VM_PAGER_BAD; 1012 } 1013 1014 maxsize = count * PAGE_SIZE; 1015 ncount = count; 1016 1017 poffset = IDX_TO_OFF(m[0]->pindex); 1018 1019 /* 1020 * If the page-aligned write is larger then the actual file we 1021 * have to invalidate pages occuring beyond the file EOF. However, 1022 * there is an edge case where a file may not be page-aligned where 1023 * the last page is partially invalid. In this case the filesystem 1024 * may not properly clear the dirty bits for the entire page (which 1025 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1026 * With the page locked we are free to fix-up the dirty bits here. 1027 * 1028 * We do not under any circumstances truncate the valid bits, as 1029 * this will screw up bogus page replacement. 1030 */ 1031 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1032 if (object->un_pager.vnp.vnp_size > poffset) { 1033 int pgoff; 1034 1035 maxsize = object->un_pager.vnp.vnp_size - poffset; 1036 ncount = btoc(maxsize); 1037 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1038 vm_page_lock_queues(); 1039 vm_page_clear_dirty(m[ncount - 1], pgoff, 1040 PAGE_SIZE - pgoff); 1041 vm_page_unlock_queues(); 1042 } 1043 } else { 1044 maxsize = 0; 1045 ncount = 0; 1046 } 1047 if (ncount < count) { 1048 for (i = ncount; i < count; i++) { 1049 rtvals[i] = VM_PAGER_BAD; 1050 } 1051 } 1052 } 1053 1054 /* 1055 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1056 * rather then a bdwrite() to prevent paging I/O from saturating 1057 * the buffer cache. Dummy-up the sequential heuristic to cause 1058 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1059 * the system decides how to cluster. 1060 */ 1061 ioflags = IO_VMIO; 1062 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1063 ioflags |= IO_SYNC; 1064 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1065 ioflags |= IO_ASYNC; 1066 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1067 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1068 1069 aiov.iov_base = (caddr_t) 0; 1070 aiov.iov_len = maxsize; 1071 auio.uio_iov = &aiov; 1072 auio.uio_iovcnt = 1; 1073 auio.uio_offset = poffset; 1074 auio.uio_segflg = UIO_NOCOPY; 1075 auio.uio_rw = UIO_WRITE; 1076 auio.uio_resid = maxsize; 1077 auio.uio_td = (struct thread *) 0; 1078 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1079 cnt.v_vnodeout++; 1080 cnt.v_vnodepgsout += ncount; 1081 1082 if (error) { 1083 printf("vnode_pager_putpages: I/O error %d\n", error); 1084 } 1085 if (auio.uio_resid) { 1086 printf("vnode_pager_putpages: residual I/O %d at %lu\n", 1087 auio.uio_resid, (u_long)m[0]->pindex); 1088 } 1089 for (i = 0; i < ncount; i++) { 1090 rtvals[i] = VM_PAGER_OK; 1091 } 1092 return rtvals[0]; 1093 } 1094 1095 struct vnode * 1096 vnode_pager_lock(vm_object_t first_object) 1097 { 1098 struct vnode *vp; 1099 vm_object_t backing_object, object; 1100 1101 VM_OBJECT_LOCK_ASSERT(first_object, MA_OWNED); 1102 for (object = first_object; object != NULL; object = backing_object) { 1103 if (object->type != OBJT_VNODE) { 1104 if ((backing_object = object->backing_object) != NULL) 1105 VM_OBJECT_LOCK(backing_object); 1106 if (object != first_object) 1107 VM_OBJECT_UNLOCK(object); 1108 continue; 1109 } 1110 retry: 1111 if (object->flags & OBJ_DEAD) { 1112 if (object != first_object) 1113 VM_OBJECT_UNLOCK(object); 1114 return NULL; 1115 } 1116 vp = object->handle; 1117 VI_LOCK(vp); 1118 VM_OBJECT_UNLOCK(object); 1119 if (first_object != object) 1120 VM_OBJECT_UNLOCK(first_object); 1121 if (vget(vp, LK_CANRECURSE | LK_INTERLOCK | LK_NOPAUSE | 1122 LK_RETRY | LK_SHARED, curthread)) { 1123 VM_OBJECT_LOCK(first_object); 1124 if (object != first_object) 1125 VM_OBJECT_LOCK(object); 1126 if (object->type != OBJT_VNODE) { 1127 if (object != first_object) 1128 VM_OBJECT_UNLOCK(object); 1129 return NULL; 1130 } 1131 printf("vnode_pager_lock: retrying\n"); 1132 goto retry; 1133 } 1134 VM_OBJECT_LOCK(first_object); 1135 return (vp); 1136 } 1137 return NULL; 1138 }
Cache object: efd749da866917406e876d28a408419d
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