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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/8.0/sys/vm/vnode_pager.c 194990 2009-06-25 18:46:30Z kib $"); 55 56 #include <sys/param.h> 57 #include <sys/systm.h> 58 #include <sys/proc.h> 59 #include <sys/vnode.h> 60 #include <sys/mount.h> 61 #include <sys/bio.h> 62 #include <sys/buf.h> 63 #include <sys/vmmeter.h> 64 #include <sys/limits.h> 65 #include <sys/conf.h> 66 #include <sys/sf_buf.h> 67 68 #include <machine/atomic.h> 69 70 #include <vm/vm.h> 71 #include <vm/vm_object.h> 72 #include <vm/vm_page.h> 73 #include <vm/vm_pager.h> 74 #include <vm/vm_map.h> 75 #include <vm/vnode_pager.h> 76 #include <vm/vm_extern.h> 77 78 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 79 daddr_t *rtaddress, int *run); 80 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 81 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 82 static void vnode_pager_dealloc(vm_object_t); 83 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 84 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); 85 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 86 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 87 vm_ooffset_t, struct ucred *cred); 88 89 struct pagerops vnodepagerops = { 90 .pgo_alloc = vnode_pager_alloc, 91 .pgo_dealloc = vnode_pager_dealloc, 92 .pgo_getpages = vnode_pager_getpages, 93 .pgo_putpages = vnode_pager_putpages, 94 .pgo_haspage = vnode_pager_haspage, 95 }; 96 97 int vnode_pbuf_freecnt; 98 99 /* Create the VM system backing object for this vnode */ 100 int 101 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 102 { 103 vm_object_t object; 104 vm_ooffset_t size = isize; 105 struct vattr va; 106 107 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 108 return (0); 109 110 while ((object = vp->v_object) != NULL) { 111 VM_OBJECT_LOCK(object); 112 if (!(object->flags & OBJ_DEAD)) { 113 VM_OBJECT_UNLOCK(object); 114 return (0); 115 } 116 VOP_UNLOCK(vp, 0); 117 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 118 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0); 119 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 120 } 121 122 if (size == 0) { 123 if (vn_isdisk(vp, NULL)) { 124 size = IDX_TO_OFF(INT_MAX); 125 } else { 126 if (VOP_GETATTR(vp, &va, td->td_ucred)) 127 return (0); 128 size = va.va_size; 129 } 130 } 131 132 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 133 /* 134 * Dereference the reference we just created. This assumes 135 * that the object is associated with the vp. 136 */ 137 VM_OBJECT_LOCK(object); 138 object->ref_count--; 139 VM_OBJECT_UNLOCK(object); 140 vrele(vp); 141 142 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 143 144 return (0); 145 } 146 147 void 148 vnode_destroy_vobject(struct vnode *vp) 149 { 150 struct vm_object *obj; 151 152 obj = vp->v_object; 153 if (obj == NULL) 154 return; 155 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 156 VM_OBJECT_LOCK(obj); 157 if (obj->ref_count == 0) { 158 /* 159 * vclean() may be called twice. The first time 160 * removes the primary reference to the object, 161 * the second time goes one further and is a 162 * special-case to terminate the object. 163 * 164 * don't double-terminate the object 165 */ 166 if ((obj->flags & OBJ_DEAD) == 0) 167 vm_object_terminate(obj); 168 else 169 VM_OBJECT_UNLOCK(obj); 170 } else { 171 /* 172 * Woe to the process that tries to page now :-). 173 */ 174 vm_pager_deallocate(obj); 175 VM_OBJECT_UNLOCK(obj); 176 } 177 vp->v_object = NULL; 178 } 179 180 181 /* 182 * Allocate (or lookup) pager for a vnode. 183 * Handle is a vnode pointer. 184 * 185 * MPSAFE 186 */ 187 vm_object_t 188 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 189 vm_ooffset_t offset, struct ucred *cred) 190 { 191 vm_object_t object; 192 struct vnode *vp; 193 194 /* 195 * Pageout to vnode, no can do yet. 196 */ 197 if (handle == NULL) 198 return (NULL); 199 200 vp = (struct vnode *) handle; 201 202 /* 203 * If the object is being terminated, wait for it to 204 * go away. 205 */ 206 retry: 207 while ((object = vp->v_object) != NULL) { 208 VM_OBJECT_LOCK(object); 209 if ((object->flags & OBJ_DEAD) == 0) 210 break; 211 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 212 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); 213 } 214 215 if (vp->v_usecount == 0) 216 panic("vnode_pager_alloc: no vnode reference"); 217 218 if (object == NULL) { 219 /* 220 * Add an object of the appropriate size 221 */ 222 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 223 224 object->un_pager.vnp.vnp_size = size; 225 226 object->handle = handle; 227 VI_LOCK(vp); 228 if (vp->v_object != NULL) { 229 /* 230 * Object has been created while we were sleeping 231 */ 232 VI_UNLOCK(vp); 233 vm_object_destroy(object); 234 goto retry; 235 } 236 vp->v_object = object; 237 VI_UNLOCK(vp); 238 } else { 239 object->ref_count++; 240 VM_OBJECT_UNLOCK(object); 241 } 242 vref(vp); 243 return (object); 244 } 245 246 /* 247 * The object must be locked. 248 */ 249 static void 250 vnode_pager_dealloc(object) 251 vm_object_t object; 252 { 253 struct vnode *vp = object->handle; 254 255 if (vp == NULL) 256 panic("vnode_pager_dealloc: pager already dealloced"); 257 258 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 259 vm_object_pip_wait(object, "vnpdea"); 260 261 object->handle = NULL; 262 object->type = OBJT_DEAD; 263 if (object->flags & OBJ_DISCONNECTWNT) { 264 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 265 wakeup(object); 266 } 267 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 268 vp->v_object = NULL; 269 vp->v_vflag &= ~VV_TEXT; 270 } 271 272 static boolean_t 273 vnode_pager_haspage(object, pindex, before, after) 274 vm_object_t object; 275 vm_pindex_t pindex; 276 int *before; 277 int *after; 278 { 279 struct vnode *vp = object->handle; 280 daddr_t bn; 281 int err; 282 daddr_t reqblock; 283 int poff; 284 int bsize; 285 int pagesperblock, blocksperpage; 286 int vfslocked; 287 288 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 289 /* 290 * If no vp or vp is doomed or marked transparent to VM, we do not 291 * have the page. 292 */ 293 if (vp == NULL || vp->v_iflag & VI_DOOMED) 294 return FALSE; 295 /* 296 * If the offset is beyond end of file we do 297 * not have the page. 298 */ 299 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 300 return FALSE; 301 302 bsize = vp->v_mount->mnt_stat.f_iosize; 303 pagesperblock = bsize / PAGE_SIZE; 304 blocksperpage = 0; 305 if (pagesperblock > 0) { 306 reqblock = pindex / pagesperblock; 307 } else { 308 blocksperpage = (PAGE_SIZE / bsize); 309 reqblock = pindex * blocksperpage; 310 } 311 VM_OBJECT_UNLOCK(object); 312 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 313 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 314 VFS_UNLOCK_GIANT(vfslocked); 315 VM_OBJECT_LOCK(object); 316 if (err) 317 return TRUE; 318 if (bn == -1) 319 return FALSE; 320 if (pagesperblock > 0) { 321 poff = pindex - (reqblock * pagesperblock); 322 if (before) { 323 *before *= pagesperblock; 324 *before += poff; 325 } 326 if (after) { 327 int numafter; 328 *after *= pagesperblock; 329 numafter = pagesperblock - (poff + 1); 330 if (IDX_TO_OFF(pindex + numafter) > 331 object->un_pager.vnp.vnp_size) { 332 numafter = 333 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 334 pindex; 335 } 336 *after += numafter; 337 } 338 } else { 339 if (before) { 340 *before /= blocksperpage; 341 } 342 343 if (after) { 344 *after /= blocksperpage; 345 } 346 } 347 return TRUE; 348 } 349 350 /* 351 * Lets the VM system know about a change in size for a file. 352 * We adjust our own internal size and flush any cached pages in 353 * the associated object that are affected by the size change. 354 * 355 * Note: this routine may be invoked as a result of a pager put 356 * operation (possibly at object termination time), so we must be careful. 357 */ 358 void 359 vnode_pager_setsize(vp, nsize) 360 struct vnode *vp; 361 vm_ooffset_t nsize; 362 { 363 vm_object_t object; 364 vm_page_t m; 365 vm_pindex_t nobjsize; 366 367 if ((object = vp->v_object) == NULL) 368 return; 369 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 370 VM_OBJECT_LOCK(object); 371 if (nsize == object->un_pager.vnp.vnp_size) { 372 /* 373 * Hasn't changed size 374 */ 375 VM_OBJECT_UNLOCK(object); 376 return; 377 } 378 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 379 if (nsize < object->un_pager.vnp.vnp_size) { 380 /* 381 * File has shrunk. Toss any cached pages beyond the new EOF. 382 */ 383 if (nobjsize < object->size) 384 vm_object_page_remove(object, nobjsize, object->size, 385 FALSE); 386 /* 387 * this gets rid of garbage at the end of a page that is now 388 * only partially backed by the vnode. 389 * 390 * XXX for some reason (I don't know yet), if we take a 391 * completely invalid page and mark it partially valid 392 * it can screw up NFS reads, so we don't allow the case. 393 */ 394 if ((nsize & PAGE_MASK) && 395 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 396 m->valid != 0) { 397 int base = (int)nsize & PAGE_MASK; 398 int size = PAGE_SIZE - base; 399 400 /* 401 * Clear out partial-page garbage in case 402 * the page has been mapped. 403 */ 404 pmap_zero_page_area(m, base, size); 405 406 /* 407 * Update the valid bits to reflect the blocks that 408 * have been zeroed. Some of these valid bits may 409 * have already been set. 410 */ 411 vm_page_set_valid(m, base, size); 412 413 /* 414 * Round "base" to the next block boundary so that the 415 * dirty bit for a partially zeroed block is not 416 * cleared. 417 */ 418 base = roundup2(base, DEV_BSIZE); 419 420 /* 421 * Clear out partial-page dirty bits. 422 * 423 * note that we do not clear out the valid 424 * bits. This would prevent bogus_page 425 * replacement from working properly. 426 */ 427 vm_page_lock_queues(); 428 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 429 vm_page_unlock_queues(); 430 } else if ((nsize & PAGE_MASK) && 431 __predict_false(object->cache != NULL)) { 432 vm_page_cache_free(object, OFF_TO_IDX(nsize), 433 nobjsize); 434 } 435 } 436 object->un_pager.vnp.vnp_size = nsize; 437 object->size = nobjsize; 438 VM_OBJECT_UNLOCK(object); 439 } 440 441 /* 442 * calculate the linear (byte) disk address of specified virtual 443 * file address 444 */ 445 static int 446 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 447 int *run) 448 { 449 int bsize; 450 int err; 451 daddr_t vblock; 452 daddr_t voffset; 453 454 if (address < 0) 455 return -1; 456 457 if (vp->v_iflag & VI_DOOMED) 458 return -1; 459 460 bsize = vp->v_mount->mnt_stat.f_iosize; 461 vblock = address / bsize; 462 voffset = address % bsize; 463 464 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 465 if (err == 0) { 466 if (*rtaddress != -1) 467 *rtaddress += voffset / DEV_BSIZE; 468 if (run) { 469 *run += 1; 470 *run *= bsize/PAGE_SIZE; 471 *run -= voffset/PAGE_SIZE; 472 } 473 } 474 475 return (err); 476 } 477 478 /* 479 * small block filesystem vnode pager input 480 */ 481 static int 482 vnode_pager_input_smlfs(object, m) 483 vm_object_t object; 484 vm_page_t m; 485 { 486 int bits, i; 487 struct vnode *vp; 488 struct bufobj *bo; 489 struct buf *bp; 490 struct sf_buf *sf; 491 daddr_t fileaddr; 492 vm_offset_t bsize; 493 int error = 0; 494 495 vp = object->handle; 496 if (vp->v_iflag & VI_DOOMED) 497 return VM_PAGER_BAD; 498 499 bsize = vp->v_mount->mnt_stat.f_iosize; 500 501 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 502 503 sf = sf_buf_alloc(m, 0); 504 505 for (i = 0; i < PAGE_SIZE / bsize; i++) { 506 vm_ooffset_t address; 507 508 bits = vm_page_bits(i * bsize, bsize); 509 if (m->valid & bits) 510 continue; 511 512 address = IDX_TO_OFF(m->pindex) + i * bsize; 513 if (address >= object->un_pager.vnp.vnp_size) { 514 fileaddr = -1; 515 } else { 516 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 517 if (error) 518 break; 519 } 520 if (fileaddr != -1) { 521 bp = getpbuf(&vnode_pbuf_freecnt); 522 523 /* build a minimal buffer header */ 524 bp->b_iocmd = BIO_READ; 525 bp->b_iodone = bdone; 526 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 527 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 528 bp->b_rcred = crhold(curthread->td_ucred); 529 bp->b_wcred = crhold(curthread->td_ucred); 530 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 531 bp->b_blkno = fileaddr; 532 pbgetbo(bo, bp); 533 bp->b_bcount = bsize; 534 bp->b_bufsize = bsize; 535 bp->b_runningbufspace = bp->b_bufsize; 536 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 537 538 /* do the input */ 539 bp->b_iooffset = dbtob(bp->b_blkno); 540 bstrategy(bp); 541 542 bwait(bp, PVM, "vnsrd"); 543 544 if ((bp->b_ioflags & BIO_ERROR) != 0) 545 error = EIO; 546 547 /* 548 * free the buffer header back to the swap buffer pool 549 */ 550 pbrelbo(bp); 551 relpbuf(bp, &vnode_pbuf_freecnt); 552 if (error) 553 break; 554 } else 555 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 556 KASSERT((m->dirty & bits) == 0, 557 ("vnode_pager_input_smlfs: page %p is dirty", m)); 558 VM_OBJECT_LOCK(object); 559 m->valid |= bits; 560 VM_OBJECT_UNLOCK(object); 561 } 562 sf_buf_free(sf); 563 if (error) { 564 return VM_PAGER_ERROR; 565 } 566 return VM_PAGER_OK; 567 } 568 569 /* 570 * old style vnode pager input routine 571 */ 572 static int 573 vnode_pager_input_old(object, m) 574 vm_object_t object; 575 vm_page_t m; 576 { 577 struct uio auio; 578 struct iovec aiov; 579 int error; 580 int size; 581 struct sf_buf *sf; 582 struct vnode *vp; 583 584 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 585 error = 0; 586 587 /* 588 * Return failure if beyond current EOF 589 */ 590 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 591 return VM_PAGER_BAD; 592 } else { 593 size = PAGE_SIZE; 594 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 595 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 596 vp = object->handle; 597 VM_OBJECT_UNLOCK(object); 598 599 /* 600 * Allocate a kernel virtual address and initialize so that 601 * we can use VOP_READ/WRITE routines. 602 */ 603 sf = sf_buf_alloc(m, 0); 604 605 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 606 aiov.iov_len = size; 607 auio.uio_iov = &aiov; 608 auio.uio_iovcnt = 1; 609 auio.uio_offset = IDX_TO_OFF(m->pindex); 610 auio.uio_segflg = UIO_SYSSPACE; 611 auio.uio_rw = UIO_READ; 612 auio.uio_resid = size; 613 auio.uio_td = curthread; 614 615 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 616 if (!error) { 617 int count = size - auio.uio_resid; 618 619 if (count == 0) 620 error = EINVAL; 621 else if (count != PAGE_SIZE) 622 bzero((caddr_t)sf_buf_kva(sf) + count, 623 PAGE_SIZE - count); 624 } 625 sf_buf_free(sf); 626 627 VM_OBJECT_LOCK(object); 628 } 629 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 630 if (!error) 631 m->valid = VM_PAGE_BITS_ALL; 632 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 633 } 634 635 /* 636 * generic vnode pager input routine 637 */ 638 639 /* 640 * Local media VFS's that do not implement their own VOP_GETPAGES 641 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 642 * to implement the previous behaviour. 643 * 644 * All other FS's should use the bypass to get to the local media 645 * backing vp's VOP_GETPAGES. 646 */ 647 static int 648 vnode_pager_getpages(object, m, count, reqpage) 649 vm_object_t object; 650 vm_page_t *m; 651 int count; 652 int reqpage; 653 { 654 int rtval; 655 struct vnode *vp; 656 int bytes = count * PAGE_SIZE; 657 int vfslocked; 658 659 vp = object->handle; 660 VM_OBJECT_UNLOCK(object); 661 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 662 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 663 KASSERT(rtval != EOPNOTSUPP, 664 ("vnode_pager: FS getpages not implemented\n")); 665 VFS_UNLOCK_GIANT(vfslocked); 666 VM_OBJECT_LOCK(object); 667 return rtval; 668 } 669 670 /* 671 * This is now called from local media FS's to operate against their 672 * own vnodes if they fail to implement VOP_GETPAGES. 673 */ 674 int 675 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 676 struct vnode *vp; 677 vm_page_t *m; 678 int bytecount; 679 int reqpage; 680 { 681 vm_object_t object; 682 vm_offset_t kva; 683 off_t foff, tfoff, nextoff; 684 int i, j, size, bsize, first; 685 daddr_t firstaddr, reqblock; 686 struct bufobj *bo; 687 int runpg; 688 int runend; 689 struct buf *bp; 690 int count; 691 int error; 692 693 object = vp->v_object; 694 count = bytecount / PAGE_SIZE; 695 696 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 697 ("vnode_pager_generic_getpages does not support devices")); 698 if (vp->v_iflag & VI_DOOMED) 699 return VM_PAGER_BAD; 700 701 bsize = vp->v_mount->mnt_stat.f_iosize; 702 703 /* get the UNDERLYING device for the file with VOP_BMAP() */ 704 705 /* 706 * originally, we did not check for an error return value -- assuming 707 * an fs always has a bmap entry point -- that assumption is wrong!!! 708 */ 709 foff = IDX_TO_OFF(m[reqpage]->pindex); 710 711 /* 712 * if we can't bmap, use old VOP code 713 */ 714 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL); 715 if (error == EOPNOTSUPP) { 716 VM_OBJECT_LOCK(object); 717 vm_page_lock_queues(); 718 for (i = 0; i < count; i++) 719 if (i != reqpage) 720 vm_page_free(m[i]); 721 vm_page_unlock_queues(); 722 PCPU_INC(cnt.v_vnodein); 723 PCPU_INC(cnt.v_vnodepgsin); 724 error = vnode_pager_input_old(object, m[reqpage]); 725 VM_OBJECT_UNLOCK(object); 726 return (error); 727 } else if (error != 0) { 728 VM_OBJECT_LOCK(object); 729 vm_page_lock_queues(); 730 for (i = 0; i < count; i++) 731 if (i != reqpage) 732 vm_page_free(m[i]); 733 vm_page_unlock_queues(); 734 VM_OBJECT_UNLOCK(object); 735 return (VM_PAGER_ERROR); 736 737 /* 738 * if the blocksize is smaller than a page size, then use 739 * special small filesystem code. NFS sometimes has a small 740 * blocksize, but it can handle large reads itself. 741 */ 742 } else if ((PAGE_SIZE / bsize) > 1 && 743 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 744 VM_OBJECT_LOCK(object); 745 vm_page_lock_queues(); 746 for (i = 0; i < count; i++) 747 if (i != reqpage) 748 vm_page_free(m[i]); 749 vm_page_unlock_queues(); 750 VM_OBJECT_UNLOCK(object); 751 PCPU_INC(cnt.v_vnodein); 752 PCPU_INC(cnt.v_vnodepgsin); 753 return vnode_pager_input_smlfs(object, m[reqpage]); 754 } 755 756 /* 757 * If we have a completely valid page available to us, we can 758 * clean up and return. Otherwise we have to re-read the 759 * media. 760 */ 761 VM_OBJECT_LOCK(object); 762 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 763 vm_page_lock_queues(); 764 for (i = 0; i < count; i++) 765 if (i != reqpage) 766 vm_page_free(m[i]); 767 vm_page_unlock_queues(); 768 VM_OBJECT_UNLOCK(object); 769 return VM_PAGER_OK; 770 } else if (reqblock == -1) { 771 pmap_zero_page(m[reqpage]); 772 KASSERT(m[reqpage]->dirty == 0, 773 ("vnode_pager_generic_getpages: page %p is dirty", m)); 774 m[reqpage]->valid = VM_PAGE_BITS_ALL; 775 vm_page_lock_queues(); 776 for (i = 0; i < count; i++) 777 if (i != reqpage) 778 vm_page_free(m[i]); 779 vm_page_unlock_queues(); 780 VM_OBJECT_UNLOCK(object); 781 return (VM_PAGER_OK); 782 } 783 m[reqpage]->valid = 0; 784 VM_OBJECT_UNLOCK(object); 785 786 /* 787 * here on direct device I/O 788 */ 789 firstaddr = -1; 790 791 /* 792 * calculate the run that includes the required page 793 */ 794 for (first = 0, i = 0; i < count; i = runend) { 795 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr, 796 &runpg) != 0) { 797 VM_OBJECT_LOCK(object); 798 vm_page_lock_queues(); 799 for (; i < count; i++) 800 if (i != reqpage) 801 vm_page_free(m[i]); 802 vm_page_unlock_queues(); 803 VM_OBJECT_UNLOCK(object); 804 return (VM_PAGER_ERROR); 805 } 806 if (firstaddr == -1) { 807 VM_OBJECT_LOCK(object); 808 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 809 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 810 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 811 (uintmax_t)foff, 812 (uintmax_t) 813 (object->un_pager.vnp.vnp_size >> 32), 814 (uintmax_t)object->un_pager.vnp.vnp_size); 815 } 816 vm_page_lock_queues(); 817 vm_page_free(m[i]); 818 vm_page_unlock_queues(); 819 VM_OBJECT_UNLOCK(object); 820 runend = i + 1; 821 first = runend; 822 continue; 823 } 824 runend = i + runpg; 825 if (runend <= reqpage) { 826 VM_OBJECT_LOCK(object); 827 vm_page_lock_queues(); 828 for (j = i; j < runend; j++) 829 vm_page_free(m[j]); 830 vm_page_unlock_queues(); 831 VM_OBJECT_UNLOCK(object); 832 } else { 833 if (runpg < (count - first)) { 834 VM_OBJECT_LOCK(object); 835 vm_page_lock_queues(); 836 for (i = first + runpg; i < count; i++) 837 vm_page_free(m[i]); 838 vm_page_unlock_queues(); 839 VM_OBJECT_UNLOCK(object); 840 count = first + runpg; 841 } 842 break; 843 } 844 first = runend; 845 } 846 847 /* 848 * the first and last page have been calculated now, move input pages 849 * to be zero based... 850 */ 851 if (first != 0) { 852 m += first; 853 count -= first; 854 reqpage -= first; 855 } 856 857 /* 858 * calculate the file virtual address for the transfer 859 */ 860 foff = IDX_TO_OFF(m[0]->pindex); 861 862 /* 863 * calculate the size of the transfer 864 */ 865 size = count * PAGE_SIZE; 866 KASSERT(count > 0, ("zero count")); 867 if ((foff + size) > object->un_pager.vnp.vnp_size) 868 size = object->un_pager.vnp.vnp_size - foff; 869 KASSERT(size > 0, ("zero size")); 870 871 /* 872 * round up physical size for real devices. 873 */ 874 if (1) { 875 int secmask = bo->bo_bsize - 1; 876 KASSERT(secmask < PAGE_SIZE && secmask > 0, 877 ("vnode_pager_generic_getpages: sector size %d too large", 878 secmask + 1)); 879 size = (size + secmask) & ~secmask; 880 } 881 882 bp = getpbuf(&vnode_pbuf_freecnt); 883 kva = (vm_offset_t) bp->b_data; 884 885 /* 886 * and map the pages to be read into the kva 887 */ 888 pmap_qenter(kva, m, count); 889 890 /* build a minimal buffer header */ 891 bp->b_iocmd = BIO_READ; 892 bp->b_iodone = bdone; 893 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 894 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 895 bp->b_rcred = crhold(curthread->td_ucred); 896 bp->b_wcred = crhold(curthread->td_ucred); 897 bp->b_blkno = firstaddr; 898 pbgetbo(bo, bp); 899 bp->b_bcount = size; 900 bp->b_bufsize = size; 901 bp->b_runningbufspace = bp->b_bufsize; 902 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 903 904 PCPU_INC(cnt.v_vnodein); 905 PCPU_ADD(cnt.v_vnodepgsin, count); 906 907 /* do the input */ 908 bp->b_iooffset = dbtob(bp->b_blkno); 909 bstrategy(bp); 910 911 bwait(bp, PVM, "vnread"); 912 913 if ((bp->b_ioflags & BIO_ERROR) != 0) 914 error = EIO; 915 916 if (!error) { 917 if (size != count * PAGE_SIZE) 918 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 919 } 920 pmap_qremove(kva, count); 921 922 /* 923 * free the buffer header back to the swap buffer pool 924 */ 925 pbrelbo(bp); 926 relpbuf(bp, &vnode_pbuf_freecnt); 927 928 VM_OBJECT_LOCK(object); 929 vm_page_lock_queues(); 930 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 931 vm_page_t mt; 932 933 nextoff = tfoff + PAGE_SIZE; 934 mt = m[i]; 935 936 if (nextoff <= object->un_pager.vnp.vnp_size) { 937 /* 938 * Read filled up entire page. 939 */ 940 mt->valid = VM_PAGE_BITS_ALL; 941 KASSERT(mt->dirty == 0, 942 ("vnode_pager_generic_getpages: page %p is dirty", 943 mt)); 944 KASSERT(!pmap_page_is_mapped(mt), 945 ("vnode_pager_generic_getpages: page %p is mapped", 946 mt)); 947 } else { 948 /* 949 * Read did not fill up entire page. 950 * 951 * Currently we do not set the entire page valid, 952 * we just try to clear the piece that we couldn't 953 * read. 954 */ 955 vm_page_set_valid(mt, 0, 956 object->un_pager.vnp.vnp_size - tfoff); 957 KASSERT((mt->dirty & vm_page_bits(0, 958 object->un_pager.vnp.vnp_size - tfoff)) == 0, 959 ("vnode_pager_generic_getpages: page %p is dirty", 960 mt)); 961 } 962 963 if (i != reqpage) { 964 965 /* 966 * whether or not to leave the page activated is up in 967 * the air, but we should put the page on a page queue 968 * somewhere. (it already is in the object). Result: 969 * It appears that empirical results show that 970 * deactivating pages is best. 971 */ 972 973 /* 974 * just in case someone was asking for this page we 975 * now tell them that it is ok to use 976 */ 977 if (!error) { 978 if (mt->oflags & VPO_WANTED) 979 vm_page_activate(mt); 980 else 981 vm_page_deactivate(mt); 982 vm_page_wakeup(mt); 983 } else { 984 vm_page_free(mt); 985 } 986 } 987 } 988 vm_page_unlock_queues(); 989 VM_OBJECT_UNLOCK(object); 990 if (error) { 991 printf("vnode_pager_getpages: I/O read error\n"); 992 } 993 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 994 } 995 996 /* 997 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 998 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 999 * vnode_pager_generic_putpages() to implement the previous behaviour. 1000 * 1001 * All other FS's should use the bypass to get to the local media 1002 * backing vp's VOP_PUTPAGES. 1003 */ 1004 static void 1005 vnode_pager_putpages(object, m, count, sync, rtvals) 1006 vm_object_t object; 1007 vm_page_t *m; 1008 int count; 1009 boolean_t sync; 1010 int *rtvals; 1011 { 1012 int rtval; 1013 struct vnode *vp; 1014 struct mount *mp; 1015 int bytes = count * PAGE_SIZE; 1016 1017 /* 1018 * Force synchronous operation if we are extremely low on memory 1019 * to prevent a low-memory deadlock. VOP operations often need to 1020 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1021 * operation ). The swapper handles the case by limiting the amount 1022 * of asynchronous I/O, but that sort of solution doesn't scale well 1023 * for the vnode pager without a lot of work. 1024 * 1025 * Also, the backing vnode's iodone routine may not wake the pageout 1026 * daemon up. This should be probably be addressed XXX. 1027 */ 1028 1029 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 1030 sync |= OBJPC_SYNC; 1031 1032 /* 1033 * Call device-specific putpages function 1034 */ 1035 vp = object->handle; 1036 VM_OBJECT_UNLOCK(object); 1037 if (vp->v_type != VREG) 1038 mp = NULL; 1039 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 1040 KASSERT(rtval != EOPNOTSUPP, 1041 ("vnode_pager: stale FS putpages\n")); 1042 VM_OBJECT_LOCK(object); 1043 } 1044 1045 1046 /* 1047 * This is now called from local media FS's to operate against their 1048 * own vnodes if they fail to implement VOP_PUTPAGES. 1049 * 1050 * This is typically called indirectly via the pageout daemon and 1051 * clustering has already typically occured, so in general we ask the 1052 * underlying filesystem to write the data out asynchronously rather 1053 * then delayed. 1054 */ 1055 int 1056 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) 1057 struct vnode *vp; 1058 vm_page_t *m; 1059 int bytecount; 1060 int flags; 1061 int *rtvals; 1062 { 1063 int i; 1064 vm_object_t object; 1065 int count; 1066 1067 int maxsize, ncount; 1068 vm_ooffset_t poffset; 1069 struct uio auio; 1070 struct iovec aiov; 1071 int error; 1072 int ioflags; 1073 int ppscheck = 0; 1074 static struct timeval lastfail; 1075 static int curfail; 1076 1077 object = vp->v_object; 1078 count = bytecount / PAGE_SIZE; 1079 1080 for (i = 0; i < count; i++) 1081 rtvals[i] = VM_PAGER_AGAIN; 1082 1083 if ((int64_t)m[0]->pindex < 0) { 1084 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1085 (long)m[0]->pindex, (u_long)m[0]->dirty); 1086 rtvals[0] = VM_PAGER_BAD; 1087 return VM_PAGER_BAD; 1088 } 1089 1090 maxsize = count * PAGE_SIZE; 1091 ncount = count; 1092 1093 poffset = IDX_TO_OFF(m[0]->pindex); 1094 1095 /* 1096 * If the page-aligned write is larger then the actual file we 1097 * have to invalidate pages occuring beyond the file EOF. However, 1098 * there is an edge case where a file may not be page-aligned where 1099 * the last page is partially invalid. In this case the filesystem 1100 * may not properly clear the dirty bits for the entire page (which 1101 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1102 * With the page locked we are free to fix-up the dirty bits here. 1103 * 1104 * We do not under any circumstances truncate the valid bits, as 1105 * this will screw up bogus page replacement. 1106 */ 1107 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1108 if (object->un_pager.vnp.vnp_size > poffset) { 1109 int pgoff; 1110 1111 maxsize = object->un_pager.vnp.vnp_size - poffset; 1112 ncount = btoc(maxsize); 1113 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1114 vm_page_lock_queues(); 1115 vm_page_clear_dirty(m[ncount - 1], pgoff, 1116 PAGE_SIZE - pgoff); 1117 vm_page_unlock_queues(); 1118 } 1119 } else { 1120 maxsize = 0; 1121 ncount = 0; 1122 } 1123 if (ncount < count) { 1124 for (i = ncount; i < count; i++) { 1125 rtvals[i] = VM_PAGER_BAD; 1126 } 1127 } 1128 } 1129 1130 /* 1131 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1132 * rather then a bdwrite() to prevent paging I/O from saturating 1133 * the buffer cache. Dummy-up the sequential heuristic to cause 1134 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1135 * the system decides how to cluster. 1136 */ 1137 ioflags = IO_VMIO; 1138 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1139 ioflags |= IO_SYNC; 1140 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1141 ioflags |= IO_ASYNC; 1142 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1143 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1144 1145 aiov.iov_base = (caddr_t) 0; 1146 aiov.iov_len = maxsize; 1147 auio.uio_iov = &aiov; 1148 auio.uio_iovcnt = 1; 1149 auio.uio_offset = poffset; 1150 auio.uio_segflg = UIO_NOCOPY; 1151 auio.uio_rw = UIO_WRITE; 1152 auio.uio_resid = maxsize; 1153 auio.uio_td = (struct thread *) 0; 1154 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1155 PCPU_INC(cnt.v_vnodeout); 1156 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1157 1158 if (error) { 1159 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1160 printf("vnode_pager_putpages: I/O error %d\n", error); 1161 } 1162 if (auio.uio_resid) { 1163 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1164 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1165 auio.uio_resid, (u_long)m[0]->pindex); 1166 } 1167 for (i = 0; i < ncount; i++) { 1168 rtvals[i] = VM_PAGER_OK; 1169 } 1170 return rtvals[0]; 1171 }
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