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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/5.4/sys/vm/vnode_pager.c 142370 2005-02-24 07:39:42Z alc $"); 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 #include <sys/sf_buf.h> 66 67 #include <vm/vm.h> 68 #include <vm/vm_object.h> 69 #include <vm/vm_page.h> 70 #include <vm/vm_pager.h> 71 #include <vm/vm_map.h> 72 #include <vm/vnode_pager.h> 73 #include <vm/vm_extern.h> 74 75 static void vnode_pager_init(void); 76 static vm_offset_t vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 77 int *run); 78 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 79 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 80 static void vnode_pager_dealloc(vm_object_t); 81 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 82 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); 83 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 84 85 struct pagerops vnodepagerops = { 86 .pgo_init = vnode_pager_init, 87 .pgo_alloc = vnode_pager_alloc, 88 .pgo_dealloc = vnode_pager_dealloc, 89 .pgo_getpages = vnode_pager_getpages, 90 .pgo_putpages = vnode_pager_putpages, 91 .pgo_haspage = vnode_pager_haspage, 92 }; 93 94 int vnode_pbuf_freecnt; 95 96 static void 97 vnode_pager_init(void) 98 { 99 100 vnode_pbuf_freecnt = nswbuf / 2 + 1; 101 } 102 103 /* 104 * Allocate (or lookup) pager for a vnode. 105 * Handle is a vnode pointer. 106 * 107 * MPSAFE 108 */ 109 vm_object_t 110 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 111 vm_ooffset_t offset) 112 { 113 vm_object_t object; 114 struct vnode *vp; 115 116 /* 117 * Pageout to vnode, no can do yet. 118 */ 119 if (handle == NULL) 120 return (NULL); 121 122 vp = (struct vnode *) handle; 123 124 ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc"); 125 126 /* 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 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 147 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); 148 } 149 150 if (vp->v_usecount == 0) 151 panic("vnode_pager_alloc: no vnode reference"); 152 153 if (object == NULL) { 154 /* 155 * And an object of the appropriate size 156 */ 157 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 158 159 object->un_pager.vnp.vnp_size = size; 160 161 object->handle = handle; 162 vp->v_object = object; 163 } else { 164 object->ref_count++; 165 VM_OBJECT_UNLOCK(object); 166 } 167 VI_LOCK(vp); 168 vp->v_usecount++; 169 vp->v_iflag &= ~VI_OLOCK; 170 if (vp->v_iflag & VI_OWANT) { 171 vp->v_iflag &= ~VI_OWANT; 172 wakeup(vp); 173 } 174 VI_UNLOCK(vp); 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 if (object->flags & OBJ_DISCONNECTWNT) { 196 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 197 wakeup(object); 198 } 199 ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc"); 200 vp->v_object = NULL; 201 vp->v_vflag &= ~(VV_TEXT | VV_OBJBUF); 202 } 203 204 static boolean_t 205 vnode_pager_haspage(object, pindex, before, after) 206 vm_object_t object; 207 vm_pindex_t pindex; 208 int *before; 209 int *after; 210 { 211 struct vnode *vp = object->handle; 212 daddr_t bn; 213 int err; 214 daddr_t reqblock; 215 int poff; 216 int bsize; 217 int pagesperblock, blocksperpage; 218 219 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 220 /* 221 * If no vp or vp is doomed or marked transparent to VM, we do not 222 * have the page. 223 */ 224 if (vp == NULL) 225 return FALSE; 226 227 VI_LOCK(vp); 228 if (vp->v_iflag & VI_DOOMED) { 229 VI_UNLOCK(vp); 230 return FALSE; 231 } 232 VI_UNLOCK(vp); 233 /* 234 * If filesystem no longer mounted or offset beyond end of file we do 235 * not have the page. 236 */ 237 if ((vp->v_mount == NULL) || 238 (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)) 239 return FALSE; 240 241 bsize = vp->v_mount->mnt_stat.f_iosize; 242 pagesperblock = bsize / PAGE_SIZE; 243 blocksperpage = 0; 244 if (pagesperblock > 0) { 245 reqblock = pindex / pagesperblock; 246 } else { 247 blocksperpage = (PAGE_SIZE / bsize); 248 reqblock = pindex * blocksperpage; 249 } 250 VM_OBJECT_UNLOCK(object); 251 mtx_lock(&Giant); 252 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 253 mtx_unlock(&Giant); 254 VM_OBJECT_LOCK(object); 255 if (err) 256 return TRUE; 257 if (bn == -1) 258 return FALSE; 259 if (pagesperblock > 0) { 260 poff = pindex - (reqblock * pagesperblock); 261 if (before) { 262 *before *= pagesperblock; 263 *before += poff; 264 } 265 if (after) { 266 int numafter; 267 *after *= pagesperblock; 268 numafter = pagesperblock - (poff + 1); 269 if (IDX_TO_OFF(pindex + numafter) > 270 object->un_pager.vnp.vnp_size) { 271 numafter = 272 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 273 pindex; 274 } 275 *after += numafter; 276 } 277 } else { 278 if (before) { 279 *before /= blocksperpage; 280 } 281 282 if (after) { 283 *after /= blocksperpage; 284 } 285 } 286 return TRUE; 287 } 288 289 /* 290 * Lets the VM system know about a change in size for a file. 291 * We adjust our own internal size and flush any cached pages in 292 * the associated object that are affected by the size change. 293 * 294 * Note: this routine may be invoked as a result of a pager put 295 * operation (possibly at object termination time), so we must be careful. 296 */ 297 void 298 vnode_pager_setsize(vp, nsize) 299 struct vnode *vp; 300 vm_ooffset_t nsize; 301 { 302 vm_object_t object; 303 vm_page_t m; 304 vm_pindex_t nobjsize; 305 306 if ((object = vp->v_object) == NULL) 307 return; 308 VM_OBJECT_LOCK(object); 309 if (nsize == object->un_pager.vnp.vnp_size) { 310 /* 311 * Hasn't changed size 312 */ 313 VM_OBJECT_UNLOCK(object); 314 return; 315 } 316 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 317 if (nsize < object->un_pager.vnp.vnp_size) { 318 /* 319 * File has shrunk. Toss any cached pages beyond the new EOF. 320 */ 321 if (nobjsize < object->size) 322 vm_object_page_remove(object, nobjsize, object->size, 323 FALSE); 324 /* 325 * this gets rid of garbage at the end of a page that is now 326 * only partially backed by the vnode. 327 * 328 * XXX for some reason (I don't know yet), if we take a 329 * completely invalid page and mark it partially valid 330 * it can screw up NFS reads, so we don't allow the case. 331 */ 332 if ((nsize & PAGE_MASK) && 333 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 334 m->valid != 0) { 335 int base = (int)nsize & PAGE_MASK; 336 int size = PAGE_SIZE - base; 337 338 /* 339 * Clear out partial-page garbage in case 340 * the page has been mapped. 341 */ 342 pmap_zero_page_area(m, base, size); 343 344 /* 345 * XXX work around SMP data integrity race 346 * by unmapping the page from user processes. 347 * The garbage we just cleared may be mapped 348 * to a user process running on another cpu 349 * and this code is not running through normal 350 * I/O channels which handle SMP issues for 351 * us, so unmap page to synchronize all cpus. 352 * 353 * XXX should vm_pager_unmap_page() have 354 * dealt with this? 355 */ 356 vm_page_lock_queues(); 357 pmap_remove_all(m); 358 359 /* 360 * Clear out partial-page dirty bits. This 361 * has the side effect of setting the valid 362 * bits, but that is ok. There are a bunch 363 * of places in the VM system where we expected 364 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 365 * case is one of them. If the page is still 366 * partially dirty, make it fully dirty. 367 * 368 * note that we do not clear out the valid 369 * bits. This would prevent bogus_page 370 * replacement from working properly. 371 */ 372 vm_page_set_validclean(m, base, size); 373 if (m->dirty != 0) 374 m->dirty = VM_PAGE_BITS_ALL; 375 vm_page_unlock_queues(); 376 } 377 } 378 object->un_pager.vnp.vnp_size = nsize; 379 object->size = nobjsize; 380 VM_OBJECT_UNLOCK(object); 381 } 382 383 /* 384 * calculate the linear (byte) disk address of specified virtual 385 * file address 386 */ 387 static vm_offset_t 388 vnode_pager_addr(vp, address, run) 389 struct vnode *vp; 390 vm_ooffset_t address; 391 int *run; 392 { 393 int rtaddress; 394 int bsize; 395 daddr_t block; 396 int err; 397 daddr_t vblock; 398 int voffset; 399 400 GIANT_REQUIRED; 401 if (address < 0) 402 return -1; 403 404 if (vp->v_mount == NULL) 405 return -1; 406 407 bsize = vp->v_mount->mnt_stat.f_iosize; 408 vblock = address / bsize; 409 voffset = address % bsize; 410 411 err = VOP_BMAP(vp, vblock, NULL, &block, run, NULL); 412 413 if (err || (block == -1)) 414 rtaddress = -1; 415 else { 416 rtaddress = block + voffset / DEV_BSIZE; 417 if (run) { 418 *run += 1; 419 *run *= bsize/PAGE_SIZE; 420 *run -= voffset/PAGE_SIZE; 421 } 422 } 423 424 return rtaddress; 425 } 426 427 /* 428 * small block filesystem vnode pager input 429 */ 430 static int 431 vnode_pager_input_smlfs(object, m) 432 vm_object_t object; 433 vm_page_t m; 434 { 435 int i; 436 struct vnode *dp, *vp; 437 struct buf *bp; 438 struct sf_buf *sf; 439 int fileaddr; 440 vm_offset_t bsize; 441 int error = 0; 442 443 GIANT_REQUIRED; 444 445 vp = object->handle; 446 if (vp->v_mount == NULL) 447 return VM_PAGER_BAD; 448 449 bsize = vp->v_mount->mnt_stat.f_iosize; 450 451 VOP_BMAP(vp, 0, &dp, 0, NULL, NULL); 452 453 sf = sf_buf_alloc(m, 0); 454 455 for (i = 0; i < PAGE_SIZE / bsize; i++) { 456 vm_ooffset_t address; 457 458 if (vm_page_bits(i * bsize, bsize) & m->valid) 459 continue; 460 461 address = IDX_TO_OFF(m->pindex) + i * bsize; 462 if (address >= object->un_pager.vnp.vnp_size) { 463 fileaddr = -1; 464 } else { 465 fileaddr = vnode_pager_addr(vp, address, NULL); 466 } 467 if (fileaddr != -1) { 468 bp = getpbuf(&vnode_pbuf_freecnt); 469 470 /* build a minimal buffer header */ 471 bp->b_iocmd = BIO_READ; 472 bp->b_iodone = bdone; 473 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 474 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 475 bp->b_rcred = crhold(curthread->td_ucred); 476 bp->b_wcred = crhold(curthread->td_ucred); 477 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 478 bp->b_blkno = fileaddr; 479 pbgetvp(dp, bp); 480 bp->b_bcount = bsize; 481 bp->b_bufsize = bsize; 482 bp->b_runningbufspace = bp->b_bufsize; 483 runningbufspace += bp->b_runningbufspace; 484 485 /* do the input */ 486 bp->b_iooffset = dbtob(bp->b_blkno); 487 if (dp->v_type == VCHR) 488 VOP_SPECSTRATEGY(bp->b_vp, bp); 489 else 490 VOP_STRATEGY(bp->b_vp, bp); 491 492 /* we definitely need to be at splvm here */ 493 494 bwait(bp, PVM, "vnsrd"); 495 496 if ((bp->b_ioflags & BIO_ERROR) != 0) 497 error = EIO; 498 499 /* 500 * free the buffer header back to the swap buffer pool 501 */ 502 relpbuf(bp, &vnode_pbuf_freecnt); 503 if (error) 504 break; 505 506 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 } else { 512 VM_OBJECT_LOCK(object); 513 vm_page_lock_queues(); 514 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 515 vm_page_unlock_queues(); 516 VM_OBJECT_UNLOCK(object); 517 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 518 } 519 } 520 sf_buf_free(sf); 521 vm_page_lock_queues(); 522 pmap_clear_modify(m); 523 vm_page_unlock_queues(); 524 if (error) { 525 return VM_PAGER_ERROR; 526 } 527 return VM_PAGER_OK; 528 529 } 530 531 532 /* 533 * old style vnode pager input routine 534 */ 535 static int 536 vnode_pager_input_old(object, m) 537 vm_object_t object; 538 vm_page_t m; 539 { 540 struct uio auio; 541 struct iovec aiov; 542 int error; 543 int size; 544 struct sf_buf *sf; 545 struct vnode *vp; 546 547 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 548 error = 0; 549 550 /* 551 * Return failure if beyond current EOF 552 */ 553 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 554 return VM_PAGER_BAD; 555 } else { 556 size = PAGE_SIZE; 557 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 558 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 559 vp = object->handle; 560 VM_OBJECT_UNLOCK(object); 561 562 /* 563 * Allocate a kernel virtual address and initialize so that 564 * we can use VOP_READ/WRITE routines. 565 */ 566 sf = sf_buf_alloc(m, 0); 567 568 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 569 aiov.iov_len = size; 570 auio.uio_iov = &aiov; 571 auio.uio_iovcnt = 1; 572 auio.uio_offset = IDX_TO_OFF(m->pindex); 573 auio.uio_segflg = UIO_SYSSPACE; 574 auio.uio_rw = UIO_READ; 575 auio.uio_resid = size; 576 auio.uio_td = curthread; 577 578 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 579 if (!error) { 580 int count = size - auio.uio_resid; 581 582 if (count == 0) 583 error = EINVAL; 584 else if (count != PAGE_SIZE) 585 bzero((caddr_t)sf_buf_kva(sf) + count, 586 PAGE_SIZE - count); 587 } 588 sf_buf_free(sf); 589 590 VM_OBJECT_LOCK(object); 591 } 592 vm_page_lock_queues(); 593 pmap_clear_modify(m); 594 vm_page_undirty(m); 595 vm_page_unlock_queues(); 596 if (!error) 597 m->valid = VM_PAGE_BITS_ALL; 598 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 599 } 600 601 /* 602 * generic vnode pager input routine 603 */ 604 605 /* 606 * Local media VFS's that do not implement their own VOP_GETPAGES 607 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 608 * to implement the previous behaviour. 609 * 610 * All other FS's should use the bypass to get to the local media 611 * backing vp's VOP_GETPAGES. 612 */ 613 static int 614 vnode_pager_getpages(object, m, count, reqpage) 615 vm_object_t object; 616 vm_page_t *m; 617 int count; 618 int reqpage; 619 { 620 int rtval; 621 struct vnode *vp; 622 int bytes = count * PAGE_SIZE; 623 624 vp = object->handle; 625 VM_OBJECT_UNLOCK(object); 626 mtx_lock(&Giant); 627 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 628 KASSERT(rtval != EOPNOTSUPP, 629 ("vnode_pager: FS getpages not implemented\n")); 630 mtx_unlock(&Giant); 631 VM_OBJECT_LOCK(object); 632 return rtval; 633 } 634 635 /* 636 * This is now called from local media FS's to operate against their 637 * own vnodes if they fail to implement VOP_GETPAGES. 638 */ 639 int 640 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 641 struct vnode *vp; 642 vm_page_t *m; 643 int bytecount; 644 int reqpage; 645 { 646 vm_object_t object; 647 vm_offset_t kva; 648 off_t foff, tfoff, nextoff; 649 int i, j, size, bsize, first, firstaddr; 650 struct vnode *dp; 651 int runpg; 652 int runend; 653 struct buf *bp; 654 int count; 655 int error = 0; 656 657 GIANT_REQUIRED; 658 object = vp->v_object; 659 count = bytecount / PAGE_SIZE; 660 661 if (vp->v_mount == NULL) 662 return VM_PAGER_BAD; 663 664 bsize = vp->v_mount->mnt_stat.f_iosize; 665 666 /* get the UNDERLYING device for the file with VOP_BMAP() */ 667 668 /* 669 * originally, we did not check for an error return value -- assuming 670 * an fs always has a bmap entry point -- that assumption is wrong!!! 671 */ 672 foff = IDX_TO_OFF(m[reqpage]->pindex); 673 674 /* 675 * if we can't bmap, use old VOP code 676 */ 677 if (VOP_BMAP(vp, 0, &dp, 0, NULL, NULL)) { 678 VM_OBJECT_LOCK(object); 679 vm_page_lock_queues(); 680 for (i = 0; i < count; i++) 681 if (i != reqpage) 682 vm_page_free(m[i]); 683 vm_page_unlock_queues(); 684 cnt.v_vnodein++; 685 cnt.v_vnodepgsin++; 686 error = vnode_pager_input_old(object, m[reqpage]); 687 VM_OBJECT_UNLOCK(object); 688 return (error); 689 690 /* 691 * if the blocksize is smaller than a page size, then use 692 * special small filesystem code. NFS sometimes has a small 693 * blocksize, but it can handle large reads itself. 694 */ 695 } else if ((PAGE_SIZE / bsize) > 1 && 696 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 697 VM_OBJECT_LOCK(object); 698 vm_page_lock_queues(); 699 for (i = 0; i < count; i++) 700 if (i != reqpage) 701 vm_page_free(m[i]); 702 vm_page_unlock_queues(); 703 VM_OBJECT_UNLOCK(object); 704 cnt.v_vnodein++; 705 cnt.v_vnodepgsin++; 706 return vnode_pager_input_smlfs(object, m[reqpage]); 707 } 708 709 /* 710 * If we have a completely valid page available to us, we can 711 * clean up and return. Otherwise we have to re-read the 712 * media. 713 */ 714 VM_OBJECT_LOCK(object); 715 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 716 vm_page_lock_queues(); 717 for (i = 0; i < count; i++) 718 if (i != reqpage) 719 vm_page_free(m[i]); 720 vm_page_unlock_queues(); 721 VM_OBJECT_UNLOCK(object); 722 return VM_PAGER_OK; 723 } 724 m[reqpage]->valid = 0; 725 VM_OBJECT_UNLOCK(object); 726 727 /* 728 * here on direct device I/O 729 */ 730 firstaddr = -1; 731 732 /* 733 * calculate the run that includes the required page 734 */ 735 for (first = 0, i = 0; i < count; i = runend) { 736 firstaddr = vnode_pager_addr(vp, 737 IDX_TO_OFF(m[i]->pindex), &runpg); 738 if (firstaddr == -1) { 739 VM_OBJECT_LOCK(object); 740 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 741 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %d, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 742 firstaddr, (uintmax_t)(foff >> 32), 743 (uintmax_t)foff, 744 (uintmax_t) 745 (object->un_pager.vnp.vnp_size >> 32), 746 (uintmax_t)object->un_pager.vnp.vnp_size); 747 } 748 vm_page_lock_queues(); 749 vm_page_free(m[i]); 750 vm_page_unlock_queues(); 751 VM_OBJECT_UNLOCK(object); 752 runend = i + 1; 753 first = runend; 754 continue; 755 } 756 runend = i + runpg; 757 if (runend <= reqpage) { 758 VM_OBJECT_LOCK(object); 759 vm_page_lock_queues(); 760 for (j = i; j < runend; j++) 761 vm_page_free(m[j]); 762 vm_page_unlock_queues(); 763 VM_OBJECT_UNLOCK(object); 764 } else { 765 if (runpg < (count - first)) { 766 VM_OBJECT_LOCK(object); 767 vm_page_lock_queues(); 768 for (i = first + runpg; i < count; i++) 769 vm_page_free(m[i]); 770 vm_page_unlock_queues(); 771 VM_OBJECT_UNLOCK(object); 772 count = first + runpg; 773 } 774 break; 775 } 776 first = runend; 777 } 778 779 /* 780 * the first and last page have been calculated now, move input pages 781 * to be zero based... 782 */ 783 if (first != 0) { 784 for (i = first; i < count; i++) { 785 m[i - first] = m[i]; 786 } 787 count -= first; 788 reqpage -= first; 789 } 790 791 /* 792 * calculate the file virtual address for the transfer 793 */ 794 foff = IDX_TO_OFF(m[0]->pindex); 795 796 /* 797 * calculate the size of the transfer 798 */ 799 size = count * PAGE_SIZE; 800 if ((foff + size) > object->un_pager.vnp.vnp_size) 801 size = object->un_pager.vnp.vnp_size - foff; 802 803 /* 804 * round up physical size for real devices. 805 */ 806 if (dp->v_type == VBLK || dp->v_type == VCHR) { 807 int secmask = dp->v_rdev->si_bsize_phys - 1; 808 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 809 size = (size + secmask) & ~secmask; 810 } 811 812 bp = getpbuf(&vnode_pbuf_freecnt); 813 kva = (vm_offset_t) bp->b_data; 814 815 /* 816 * and map the pages to be read into the kva 817 */ 818 pmap_qenter(kva, m, count); 819 820 /* build a minimal buffer header */ 821 bp->b_iocmd = BIO_READ; 822 bp->b_iodone = bdone; 823 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 824 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 825 bp->b_rcred = crhold(curthread->td_ucred); 826 bp->b_wcred = crhold(curthread->td_ucred); 827 bp->b_blkno = firstaddr; 828 pbgetvp(dp, bp); 829 bp->b_bcount = size; 830 bp->b_bufsize = size; 831 bp->b_runningbufspace = bp->b_bufsize; 832 runningbufspace += bp->b_runningbufspace; 833 834 cnt.v_vnodein++; 835 cnt.v_vnodepgsin += count; 836 837 /* do the input */ 838 bp->b_iooffset = dbtob(bp->b_blkno); 839 if (dp->v_type == VCHR) 840 VOP_SPECSTRATEGY(bp->b_vp, bp); 841 else 842 VOP_STRATEGY(bp->b_vp, bp); 843 844 bwait(bp, PVM, "vnread"); 845 846 if ((bp->b_ioflags & BIO_ERROR) != 0) 847 error = EIO; 848 849 if (!error) { 850 if (size != count * PAGE_SIZE) 851 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 852 } 853 pmap_qremove(kva, count); 854 855 /* 856 * free the buffer header back to the swap buffer pool 857 */ 858 relpbuf(bp, &vnode_pbuf_freecnt); 859 860 VM_OBJECT_LOCK(object); 861 vm_page_lock_queues(); 862 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 863 vm_page_t mt; 864 865 nextoff = tfoff + PAGE_SIZE; 866 mt = m[i]; 867 868 if (nextoff <= object->un_pager.vnp.vnp_size) { 869 /* 870 * Read filled up entire page. 871 */ 872 mt->valid = VM_PAGE_BITS_ALL; 873 vm_page_undirty(mt); /* should be an assert? XXX */ 874 pmap_clear_modify(mt); 875 } else { 876 /* 877 * Read did not fill up entire page. Since this 878 * is getpages, the page may be mapped, so we have 879 * to zero the invalid portions of the page even 880 * though we aren't setting them valid. 881 * 882 * Currently we do not set the entire page valid, 883 * we just try to clear the piece that we couldn't 884 * read. 885 */ 886 vm_page_set_validclean(mt, 0, 887 object->un_pager.vnp.vnp_size - tfoff); 888 /* handled by vm_fault now */ 889 /* vm_page_zero_invalid(mt, FALSE); */ 890 } 891 892 if (i != reqpage) { 893 894 /* 895 * whether or not to leave the page activated is up in 896 * the air, but we should put the page on a page queue 897 * somewhere. (it already is in the object). Result: 898 * It appears that empirical results show that 899 * deactivating pages is best. 900 */ 901 902 /* 903 * just in case someone was asking for this page we 904 * now tell them that it is ok to use 905 */ 906 if (!error) { 907 if (mt->flags & PG_WANTED) 908 vm_page_activate(mt); 909 else 910 vm_page_deactivate(mt); 911 vm_page_wakeup(mt); 912 } else { 913 vm_page_free(mt); 914 } 915 } 916 } 917 vm_page_unlock_queues(); 918 VM_OBJECT_UNLOCK(object); 919 if (error) { 920 printf("vnode_pager_getpages: I/O read error\n"); 921 } 922 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 923 } 924 925 /* 926 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 927 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 928 * vnode_pager_generic_putpages() to implement the previous behaviour. 929 * 930 * All other FS's should use the bypass to get to the local media 931 * backing vp's VOP_PUTPAGES. 932 */ 933 static void 934 vnode_pager_putpages(object, m, count, sync, rtvals) 935 vm_object_t object; 936 vm_page_t *m; 937 int count; 938 boolean_t sync; 939 int *rtvals; 940 { 941 int rtval; 942 struct vnode *vp; 943 struct mount *mp; 944 int bytes = count * PAGE_SIZE; 945 946 GIANT_REQUIRED; 947 /* 948 * Force synchronous operation if we are extremely low on memory 949 * to prevent a low-memory deadlock. VOP operations often need to 950 * allocate more memory to initiate the I/O ( i.e. do a BMAP 951 * operation ). The swapper handles the case by limiting the amount 952 * of asynchronous I/O, but that sort of solution doesn't scale well 953 * for the vnode pager without a lot of work. 954 * 955 * Also, the backing vnode's iodone routine may not wake the pageout 956 * daemon up. This should be probably be addressed XXX. 957 */ 958 959 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 960 sync |= OBJPC_SYNC; 961 962 /* 963 * Call device-specific putpages function 964 */ 965 vp = object->handle; 966 VM_OBJECT_UNLOCK(object); 967 if (vp->v_type != VREG) 968 mp = NULL; 969 (void)vn_start_write(vp, &mp, V_WAIT); 970 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 971 KASSERT(rtval != EOPNOTSUPP, 972 ("vnode_pager: stale FS putpages\n")); 973 vn_finished_write(mp); 974 VM_OBJECT_LOCK(object); 975 } 976 977 978 /* 979 * This is now called from local media FS's to operate against their 980 * own vnodes if they fail to implement VOP_PUTPAGES. 981 * 982 * This is typically called indirectly via the pageout daemon and 983 * clustering has already typically occured, so in general we ask the 984 * underlying filesystem to write the data out asynchronously rather 985 * then delayed. 986 */ 987 int 988 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) 989 struct vnode *vp; 990 vm_page_t *m; 991 int bytecount; 992 int flags; 993 int *rtvals; 994 { 995 int i; 996 vm_object_t object; 997 int count; 998 999 int maxsize, ncount; 1000 vm_ooffset_t poffset; 1001 struct uio auio; 1002 struct iovec aiov; 1003 int error; 1004 int ioflags; 1005 1006 GIANT_REQUIRED; 1007 object = vp->v_object; 1008 count = bytecount / PAGE_SIZE; 1009 1010 for (i = 0; i < count; i++) 1011 rtvals[i] = VM_PAGER_AGAIN; 1012 1013 if ((int64_t)m[0]->pindex < 0) { 1014 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1015 (long)m[0]->pindex, (u_long)m[0]->dirty); 1016 rtvals[0] = VM_PAGER_BAD; 1017 return VM_PAGER_BAD; 1018 } 1019 1020 maxsize = count * PAGE_SIZE; 1021 ncount = count; 1022 1023 poffset = IDX_TO_OFF(m[0]->pindex); 1024 1025 /* 1026 * If the page-aligned write is larger then the actual file we 1027 * have to invalidate pages occuring beyond the file EOF. However, 1028 * there is an edge case where a file may not be page-aligned where 1029 * the last page is partially invalid. In this case the filesystem 1030 * may not properly clear the dirty bits for the entire page (which 1031 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1032 * With the page locked we are free to fix-up the dirty bits here. 1033 * 1034 * We do not under any circumstances truncate the valid bits, as 1035 * this will screw up bogus page replacement. 1036 */ 1037 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1038 if (object->un_pager.vnp.vnp_size > poffset) { 1039 int pgoff; 1040 1041 maxsize = object->un_pager.vnp.vnp_size - poffset; 1042 ncount = btoc(maxsize); 1043 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1044 vm_page_lock_queues(); 1045 vm_page_clear_dirty(m[ncount - 1], pgoff, 1046 PAGE_SIZE - pgoff); 1047 vm_page_unlock_queues(); 1048 } 1049 } else { 1050 maxsize = 0; 1051 ncount = 0; 1052 } 1053 if (ncount < count) { 1054 for (i = ncount; i < count; i++) { 1055 rtvals[i] = VM_PAGER_BAD; 1056 } 1057 } 1058 } 1059 1060 /* 1061 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1062 * rather then a bdwrite() to prevent paging I/O from saturating 1063 * the buffer cache. Dummy-up the sequential heuristic to cause 1064 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1065 * the system decides how to cluster. 1066 */ 1067 ioflags = IO_VMIO; 1068 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1069 ioflags |= IO_SYNC; 1070 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1071 ioflags |= IO_ASYNC; 1072 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1073 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1074 1075 aiov.iov_base = (caddr_t) 0; 1076 aiov.iov_len = maxsize; 1077 auio.uio_iov = &aiov; 1078 auio.uio_iovcnt = 1; 1079 auio.uio_offset = poffset; 1080 auio.uio_segflg = UIO_NOCOPY; 1081 auio.uio_rw = UIO_WRITE; 1082 auio.uio_resid = maxsize; 1083 auio.uio_td = (struct thread *) 0; 1084 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1085 cnt.v_vnodeout++; 1086 cnt.v_vnodepgsout += ncount; 1087 1088 if (error) { 1089 printf("vnode_pager_putpages: I/O error %d\n", error); 1090 } 1091 if (auio.uio_resid) { 1092 printf("vnode_pager_putpages: residual I/O %d at %lu\n", 1093 auio.uio_resid, (u_long)m[0]->pindex); 1094 } 1095 for (i = 0; i < ncount; i++) { 1096 rtvals[i] = VM_PAGER_OK; 1097 } 1098 return rtvals[0]; 1099 } 1100 1101 struct vnode * 1102 vnode_pager_lock(vm_object_t first_object) 1103 { 1104 struct vnode *vp; 1105 vm_object_t backing_object, object; 1106 1107 VM_OBJECT_LOCK_ASSERT(first_object, MA_OWNED); 1108 for (object = first_object; object != NULL; object = backing_object) { 1109 if (object->type != OBJT_VNODE) { 1110 if ((backing_object = object->backing_object) != NULL) 1111 VM_OBJECT_LOCK(backing_object); 1112 if (object != first_object) 1113 VM_OBJECT_UNLOCK(object); 1114 continue; 1115 } 1116 retry: 1117 if (object->flags & OBJ_DEAD) { 1118 if (object != first_object) 1119 VM_OBJECT_UNLOCK(object); 1120 return NULL; 1121 } 1122 vp = object->handle; 1123 VI_LOCK(vp); 1124 VM_OBJECT_UNLOCK(object); 1125 if (first_object != object) 1126 VM_OBJECT_UNLOCK(first_object); 1127 if (vget(vp, LK_CANRECURSE | LK_INTERLOCK | LK_NOPAUSE | 1128 LK_RETRY | LK_SHARED, curthread)) { 1129 VM_OBJECT_LOCK(first_object); 1130 if (object != first_object) 1131 VM_OBJECT_LOCK(object); 1132 if (object->type != OBJT_VNODE) { 1133 if (object != first_object) 1134 VM_OBJECT_UNLOCK(object); 1135 return NULL; 1136 } 1137 printf("vnode_pager_lock: retrying\n"); 1138 goto retry; 1139 } 1140 VM_OBJECT_LOCK(first_object); 1141 return (vp); 1142 } 1143 return NULL; 1144 }
Cache object: c10d96f71f91145354ce49cf4e41b29e
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