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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/10.0/sys/vm/vnode_pager.c 254138 2013-08-09 11:11:11Z attilio $"); 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/rwlock.h> 67 #include <sys/sf_buf.h> 68 69 #include <machine/atomic.h> 70 71 #include <vm/vm.h> 72 #include <vm/vm_param.h> 73 #include <vm/vm_object.h> 74 #include <vm/vm_page.h> 75 #include <vm/vm_pager.h> 76 #include <vm/vm_map.h> 77 #include <vm/vnode_pager.h> 78 #include <vm/vm_extern.h> 79 80 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 81 daddr_t *rtaddress, int *run); 82 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 83 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 84 static void vnode_pager_dealloc(vm_object_t); 85 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 86 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); 87 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 88 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 89 vm_ooffset_t, struct ucred *cred); 90 91 struct pagerops vnodepagerops = { 92 .pgo_alloc = vnode_pager_alloc, 93 .pgo_dealloc = vnode_pager_dealloc, 94 .pgo_getpages = vnode_pager_getpages, 95 .pgo_putpages = vnode_pager_putpages, 96 .pgo_haspage = vnode_pager_haspage, 97 }; 98 99 int vnode_pbuf_freecnt; 100 101 /* Create the VM system backing object for this vnode */ 102 int 103 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 104 { 105 vm_object_t object; 106 vm_ooffset_t size = isize; 107 struct vattr va; 108 109 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 110 return (0); 111 112 while ((object = vp->v_object) != NULL) { 113 VM_OBJECT_WLOCK(object); 114 if (!(object->flags & OBJ_DEAD)) { 115 VM_OBJECT_WUNLOCK(object); 116 return (0); 117 } 118 VOP_UNLOCK(vp, 0); 119 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 120 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0); 121 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 122 } 123 124 if (size == 0) { 125 if (vn_isdisk(vp, NULL)) { 126 size = IDX_TO_OFF(INT_MAX); 127 } else { 128 if (VOP_GETATTR(vp, &va, td->td_ucred)) 129 return (0); 130 size = va.va_size; 131 } 132 } 133 134 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 135 /* 136 * Dereference the reference we just created. This assumes 137 * that the object is associated with the vp. 138 */ 139 VM_OBJECT_WLOCK(object); 140 object->ref_count--; 141 VM_OBJECT_WUNLOCK(object); 142 vrele(vp); 143 144 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 145 146 return (0); 147 } 148 149 void 150 vnode_destroy_vobject(struct vnode *vp) 151 { 152 struct vm_object *obj; 153 154 obj = vp->v_object; 155 if (obj == NULL) 156 return; 157 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 158 VM_OBJECT_WLOCK(obj); 159 if (obj->ref_count == 0) { 160 /* 161 * don't double-terminate the object 162 */ 163 if ((obj->flags & OBJ_DEAD) == 0) 164 vm_object_terminate(obj); 165 else 166 VM_OBJECT_WUNLOCK(obj); 167 } else { 168 /* 169 * Woe to the process that tries to page now :-). 170 */ 171 vm_pager_deallocate(obj); 172 VM_OBJECT_WUNLOCK(obj); 173 } 174 vp->v_object = NULL; 175 } 176 177 178 /* 179 * Allocate (or lookup) pager for a vnode. 180 * Handle is a vnode pointer. 181 * 182 * MPSAFE 183 */ 184 vm_object_t 185 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 186 vm_ooffset_t offset, struct ucred *cred) 187 { 188 vm_object_t object; 189 struct vnode *vp; 190 191 /* 192 * Pageout to vnode, no can do yet. 193 */ 194 if (handle == NULL) 195 return (NULL); 196 197 vp = (struct vnode *) handle; 198 199 /* 200 * If the object is being terminated, wait for it to 201 * go away. 202 */ 203 retry: 204 while ((object = vp->v_object) != NULL) { 205 VM_OBJECT_WLOCK(object); 206 if ((object->flags & OBJ_DEAD) == 0) 207 break; 208 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 209 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0); 210 } 211 212 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference")); 213 214 if (object == NULL) { 215 /* 216 * Add an object of the appropriate size 217 */ 218 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 219 220 object->un_pager.vnp.vnp_size = size; 221 object->un_pager.vnp.writemappings = 0; 222 223 object->handle = handle; 224 VI_LOCK(vp); 225 if (vp->v_object != NULL) { 226 /* 227 * Object has been created while we were sleeping 228 */ 229 VI_UNLOCK(vp); 230 vm_object_destroy(object); 231 goto retry; 232 } 233 vp->v_object = object; 234 VI_UNLOCK(vp); 235 } else { 236 object->ref_count++; 237 VM_OBJECT_WUNLOCK(object); 238 } 239 vref(vp); 240 return (object); 241 } 242 243 /* 244 * The object must be locked. 245 */ 246 static void 247 vnode_pager_dealloc(object) 248 vm_object_t object; 249 { 250 struct vnode *vp; 251 int refs; 252 253 vp = object->handle; 254 if (vp == NULL) 255 panic("vnode_pager_dealloc: pager already dealloced"); 256 257 VM_OBJECT_ASSERT_WLOCKED(object); 258 vm_object_pip_wait(object, "vnpdea"); 259 refs = object->ref_count; 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 if (object->un_pager.vnp.writemappings > 0) { 269 object->un_pager.vnp.writemappings = 0; 270 VOP_ADD_WRITECOUNT(vp, -1); 271 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 272 __func__, vp, vp->v_writecount); 273 } 274 vp->v_object = NULL; 275 VOP_UNSET_TEXT(vp); 276 VM_OBJECT_WUNLOCK(object); 277 while (refs-- > 0) 278 vunref(vp); 279 VM_OBJECT_WLOCK(object); 280 } 281 282 static boolean_t 283 vnode_pager_haspage(object, pindex, before, after) 284 vm_object_t object; 285 vm_pindex_t pindex; 286 int *before; 287 int *after; 288 { 289 struct vnode *vp = object->handle; 290 daddr_t bn; 291 int err; 292 daddr_t reqblock; 293 int poff; 294 int bsize; 295 int pagesperblock, blocksperpage; 296 297 VM_OBJECT_ASSERT_WLOCKED(object); 298 /* 299 * If no vp or vp is doomed or marked transparent to VM, we do not 300 * have the page. 301 */ 302 if (vp == NULL || vp->v_iflag & VI_DOOMED) 303 return FALSE; 304 /* 305 * If the offset is beyond end of file we do 306 * not have the page. 307 */ 308 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 309 return FALSE; 310 311 bsize = vp->v_mount->mnt_stat.f_iosize; 312 pagesperblock = bsize / PAGE_SIZE; 313 blocksperpage = 0; 314 if (pagesperblock > 0) { 315 reqblock = pindex / pagesperblock; 316 } else { 317 blocksperpage = (PAGE_SIZE / bsize); 318 reqblock = pindex * blocksperpage; 319 } 320 VM_OBJECT_WUNLOCK(object); 321 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 322 VM_OBJECT_WLOCK(object); 323 if (err) 324 return TRUE; 325 if (bn == -1) 326 return FALSE; 327 if (pagesperblock > 0) { 328 poff = pindex - (reqblock * pagesperblock); 329 if (before) { 330 *before *= pagesperblock; 331 *before += poff; 332 } 333 if (after) { 334 int numafter; 335 *after *= pagesperblock; 336 numafter = pagesperblock - (poff + 1); 337 if (IDX_TO_OFF(pindex + numafter) > 338 object->un_pager.vnp.vnp_size) { 339 numafter = 340 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 341 pindex; 342 } 343 *after += numafter; 344 } 345 } else { 346 if (before) { 347 *before /= blocksperpage; 348 } 349 350 if (after) { 351 *after /= blocksperpage; 352 } 353 } 354 return TRUE; 355 } 356 357 /* 358 * Lets the VM system know about a change in size for a file. 359 * We adjust our own internal size and flush any cached pages in 360 * the associated object that are affected by the size change. 361 * 362 * Note: this routine may be invoked as a result of a pager put 363 * operation (possibly at object termination time), so we must be careful. 364 */ 365 void 366 vnode_pager_setsize(vp, nsize) 367 struct vnode *vp; 368 vm_ooffset_t nsize; 369 { 370 vm_object_t object; 371 vm_page_t m; 372 vm_pindex_t nobjsize; 373 374 if ((object = vp->v_object) == NULL) 375 return; 376 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 377 VM_OBJECT_WLOCK(object); 378 if (object->type == OBJT_DEAD) { 379 VM_OBJECT_WUNLOCK(object); 380 return; 381 } 382 KASSERT(object->type == OBJT_VNODE, 383 ("not vnode-backed object %p", object)); 384 if (nsize == object->un_pager.vnp.vnp_size) { 385 /* 386 * Hasn't changed size 387 */ 388 VM_OBJECT_WUNLOCK(object); 389 return; 390 } 391 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 392 if (nsize < object->un_pager.vnp.vnp_size) { 393 /* 394 * File has shrunk. Toss any cached pages beyond the new EOF. 395 */ 396 if (nobjsize < object->size) 397 vm_object_page_remove(object, nobjsize, object->size, 398 0); 399 /* 400 * this gets rid of garbage at the end of a page that is now 401 * only partially backed by the vnode. 402 * 403 * XXX for some reason (I don't know yet), if we take a 404 * completely invalid page and mark it partially valid 405 * it can screw up NFS reads, so we don't allow the case. 406 */ 407 if ((nsize & PAGE_MASK) && 408 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 409 m->valid != 0) { 410 int base = (int)nsize & PAGE_MASK; 411 int size = PAGE_SIZE - base; 412 413 /* 414 * Clear out partial-page garbage in case 415 * the page has been mapped. 416 */ 417 pmap_zero_page_area(m, base, size); 418 419 /* 420 * Update the valid bits to reflect the blocks that 421 * have been zeroed. Some of these valid bits may 422 * have already been set. 423 */ 424 vm_page_set_valid_range(m, base, size); 425 426 /* 427 * Round "base" to the next block boundary so that the 428 * dirty bit for a partially zeroed block is not 429 * cleared. 430 */ 431 base = roundup2(base, DEV_BSIZE); 432 433 /* 434 * Clear out partial-page dirty bits. 435 * 436 * note that we do not clear out the valid 437 * bits. This would prevent bogus_page 438 * replacement from working properly. 439 */ 440 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 441 } else if ((nsize & PAGE_MASK) && 442 vm_page_is_cached(object, OFF_TO_IDX(nsize))) { 443 vm_page_cache_free(object, OFF_TO_IDX(nsize), 444 nobjsize); 445 } 446 } 447 object->un_pager.vnp.vnp_size = nsize; 448 object->size = nobjsize; 449 VM_OBJECT_WUNLOCK(object); 450 } 451 452 /* 453 * calculate the linear (byte) disk address of specified virtual 454 * file address 455 */ 456 static int 457 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 458 int *run) 459 { 460 int bsize; 461 int err; 462 daddr_t vblock; 463 daddr_t voffset; 464 465 if (address < 0) 466 return -1; 467 468 if (vp->v_iflag & VI_DOOMED) 469 return -1; 470 471 bsize = vp->v_mount->mnt_stat.f_iosize; 472 vblock = address / bsize; 473 voffset = address % bsize; 474 475 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 476 if (err == 0) { 477 if (*rtaddress != -1) 478 *rtaddress += voffset / DEV_BSIZE; 479 if (run) { 480 *run += 1; 481 *run *= bsize/PAGE_SIZE; 482 *run -= voffset/PAGE_SIZE; 483 } 484 } 485 486 return (err); 487 } 488 489 /* 490 * small block filesystem vnode pager input 491 */ 492 static int 493 vnode_pager_input_smlfs(object, m) 494 vm_object_t object; 495 vm_page_t m; 496 { 497 struct vnode *vp; 498 struct bufobj *bo; 499 struct buf *bp; 500 struct sf_buf *sf; 501 daddr_t fileaddr; 502 vm_offset_t bsize; 503 vm_page_bits_t bits; 504 int error, i; 505 506 error = 0; 507 vp = object->handle; 508 if (vp->v_iflag & VI_DOOMED) 509 return VM_PAGER_BAD; 510 511 bsize = vp->v_mount->mnt_stat.f_iosize; 512 513 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 514 515 sf = sf_buf_alloc(m, 0); 516 517 for (i = 0; i < PAGE_SIZE / bsize; i++) { 518 vm_ooffset_t address; 519 520 bits = vm_page_bits(i * bsize, bsize); 521 if (m->valid & bits) 522 continue; 523 524 address = IDX_TO_OFF(m->pindex) + i * bsize; 525 if (address >= object->un_pager.vnp.vnp_size) { 526 fileaddr = -1; 527 } else { 528 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 529 if (error) 530 break; 531 } 532 if (fileaddr != -1) { 533 bp = getpbuf(&vnode_pbuf_freecnt); 534 535 /* build a minimal buffer header */ 536 bp->b_iocmd = BIO_READ; 537 bp->b_iodone = bdone; 538 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 539 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 540 bp->b_rcred = crhold(curthread->td_ucred); 541 bp->b_wcred = crhold(curthread->td_ucred); 542 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 543 bp->b_blkno = fileaddr; 544 pbgetbo(bo, bp); 545 bp->b_vp = vp; 546 bp->b_bcount = bsize; 547 bp->b_bufsize = bsize; 548 bp->b_runningbufspace = bp->b_bufsize; 549 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 550 551 /* do the input */ 552 bp->b_iooffset = dbtob(bp->b_blkno); 553 bstrategy(bp); 554 555 bwait(bp, PVM, "vnsrd"); 556 557 if ((bp->b_ioflags & BIO_ERROR) != 0) 558 error = EIO; 559 560 /* 561 * free the buffer header back to the swap buffer pool 562 */ 563 bp->b_vp = NULL; 564 pbrelbo(bp); 565 relpbuf(bp, &vnode_pbuf_freecnt); 566 if (error) 567 break; 568 } else 569 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 570 KASSERT((m->dirty & bits) == 0, 571 ("vnode_pager_input_smlfs: page %p is dirty", m)); 572 VM_OBJECT_WLOCK(object); 573 m->valid |= bits; 574 VM_OBJECT_WUNLOCK(object); 575 } 576 sf_buf_free(sf); 577 if (error) { 578 return VM_PAGER_ERROR; 579 } 580 return VM_PAGER_OK; 581 } 582 583 /* 584 * old style vnode pager input routine 585 */ 586 static int 587 vnode_pager_input_old(object, m) 588 vm_object_t object; 589 vm_page_t m; 590 { 591 struct uio auio; 592 struct iovec aiov; 593 int error; 594 int size; 595 struct sf_buf *sf; 596 struct vnode *vp; 597 598 VM_OBJECT_ASSERT_WLOCKED(object); 599 error = 0; 600 601 /* 602 * Return failure if beyond current EOF 603 */ 604 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 605 return VM_PAGER_BAD; 606 } else { 607 size = PAGE_SIZE; 608 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 609 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 610 vp = object->handle; 611 VM_OBJECT_WUNLOCK(object); 612 613 /* 614 * Allocate a kernel virtual address and initialize so that 615 * we can use VOP_READ/WRITE routines. 616 */ 617 sf = sf_buf_alloc(m, 0); 618 619 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 620 aiov.iov_len = size; 621 auio.uio_iov = &aiov; 622 auio.uio_iovcnt = 1; 623 auio.uio_offset = IDX_TO_OFF(m->pindex); 624 auio.uio_segflg = UIO_SYSSPACE; 625 auio.uio_rw = UIO_READ; 626 auio.uio_resid = size; 627 auio.uio_td = curthread; 628 629 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 630 if (!error) { 631 int count = size - auio.uio_resid; 632 633 if (count == 0) 634 error = EINVAL; 635 else if (count != PAGE_SIZE) 636 bzero((caddr_t)sf_buf_kva(sf) + count, 637 PAGE_SIZE - count); 638 } 639 sf_buf_free(sf); 640 641 VM_OBJECT_WLOCK(object); 642 } 643 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 644 if (!error) 645 m->valid = VM_PAGE_BITS_ALL; 646 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 647 } 648 649 /* 650 * generic vnode pager input routine 651 */ 652 653 /* 654 * Local media VFS's that do not implement their own VOP_GETPAGES 655 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 656 * to implement the previous behaviour. 657 * 658 * All other FS's should use the bypass to get to the local media 659 * backing vp's VOP_GETPAGES. 660 */ 661 static int 662 vnode_pager_getpages(object, m, count, reqpage) 663 vm_object_t object; 664 vm_page_t *m; 665 int count; 666 int reqpage; 667 { 668 int rtval; 669 struct vnode *vp; 670 int bytes = count * PAGE_SIZE; 671 672 vp = object->handle; 673 VM_OBJECT_WUNLOCK(object); 674 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 675 KASSERT(rtval != EOPNOTSUPP, 676 ("vnode_pager: FS getpages not implemented\n")); 677 VM_OBJECT_WLOCK(object); 678 return rtval; 679 } 680 681 /* 682 * This is now called from local media FS's to operate against their 683 * own vnodes if they fail to implement VOP_GETPAGES. 684 */ 685 int 686 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 687 struct vnode *vp; 688 vm_page_t *m; 689 int bytecount; 690 int reqpage; 691 { 692 vm_object_t object; 693 vm_offset_t kva; 694 off_t foff, tfoff, nextoff; 695 int i, j, size, bsize, first; 696 daddr_t firstaddr, reqblock; 697 struct bufobj *bo; 698 int runpg; 699 int runend; 700 struct buf *bp; 701 struct mount *mp; 702 int count; 703 int error; 704 705 object = vp->v_object; 706 count = bytecount / PAGE_SIZE; 707 708 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 709 ("vnode_pager_generic_getpages does not support devices")); 710 if (vp->v_iflag & VI_DOOMED) 711 return VM_PAGER_BAD; 712 713 bsize = vp->v_mount->mnt_stat.f_iosize; 714 715 /* get the UNDERLYING device for the file with VOP_BMAP() */ 716 717 /* 718 * originally, we did not check for an error return value -- assuming 719 * an fs always has a bmap entry point -- that assumption is wrong!!! 720 */ 721 foff = IDX_TO_OFF(m[reqpage]->pindex); 722 723 /* 724 * if we can't bmap, use old VOP code 725 */ 726 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL); 727 if (error == EOPNOTSUPP) { 728 VM_OBJECT_WLOCK(object); 729 730 for (i = 0; i < count; i++) 731 if (i != reqpage) { 732 vm_page_lock(m[i]); 733 vm_page_free(m[i]); 734 vm_page_unlock(m[i]); 735 } 736 PCPU_INC(cnt.v_vnodein); 737 PCPU_INC(cnt.v_vnodepgsin); 738 error = vnode_pager_input_old(object, m[reqpage]); 739 VM_OBJECT_WUNLOCK(object); 740 return (error); 741 } else if (error != 0) { 742 VM_OBJECT_WLOCK(object); 743 for (i = 0; i < count; i++) 744 if (i != reqpage) { 745 vm_page_lock(m[i]); 746 vm_page_free(m[i]); 747 vm_page_unlock(m[i]); 748 } 749 VM_OBJECT_WUNLOCK(object); 750 return (VM_PAGER_ERROR); 751 752 /* 753 * if the blocksize is smaller than a page size, then use 754 * special small filesystem code. NFS sometimes has a small 755 * blocksize, but it can handle large reads itself. 756 */ 757 } else if ((PAGE_SIZE / bsize) > 1 && 758 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 759 VM_OBJECT_WLOCK(object); 760 for (i = 0; i < count; i++) 761 if (i != reqpage) { 762 vm_page_lock(m[i]); 763 vm_page_free(m[i]); 764 vm_page_unlock(m[i]); 765 } 766 VM_OBJECT_WUNLOCK(object); 767 PCPU_INC(cnt.v_vnodein); 768 PCPU_INC(cnt.v_vnodepgsin); 769 return vnode_pager_input_smlfs(object, m[reqpage]); 770 } 771 772 /* 773 * If we have a completely valid page available to us, we can 774 * clean up and return. Otherwise we have to re-read the 775 * media. 776 */ 777 VM_OBJECT_WLOCK(object); 778 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 779 for (i = 0; i < count; i++) 780 if (i != reqpage) { 781 vm_page_lock(m[i]); 782 vm_page_free(m[i]); 783 vm_page_unlock(m[i]); 784 } 785 VM_OBJECT_WUNLOCK(object); 786 return VM_PAGER_OK; 787 } else if (reqblock == -1) { 788 pmap_zero_page(m[reqpage]); 789 KASSERT(m[reqpage]->dirty == 0, 790 ("vnode_pager_generic_getpages: page %p is dirty", m)); 791 m[reqpage]->valid = VM_PAGE_BITS_ALL; 792 for (i = 0; i < count; i++) 793 if (i != reqpage) { 794 vm_page_lock(m[i]); 795 vm_page_free(m[i]); 796 vm_page_unlock(m[i]); 797 } 798 VM_OBJECT_WUNLOCK(object); 799 return (VM_PAGER_OK); 800 } 801 m[reqpage]->valid = 0; 802 VM_OBJECT_WUNLOCK(object); 803 804 /* 805 * here on direct device I/O 806 */ 807 firstaddr = -1; 808 809 /* 810 * calculate the run that includes the required page 811 */ 812 for (first = 0, i = 0; i < count; i = runend) { 813 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr, 814 &runpg) != 0) { 815 VM_OBJECT_WLOCK(object); 816 for (; i < count; i++) 817 if (i != reqpage) { 818 vm_page_lock(m[i]); 819 vm_page_free(m[i]); 820 vm_page_unlock(m[i]); 821 } 822 VM_OBJECT_WUNLOCK(object); 823 return (VM_PAGER_ERROR); 824 } 825 if (firstaddr == -1) { 826 VM_OBJECT_WLOCK(object); 827 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 828 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 829 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 830 (uintmax_t)foff, 831 (uintmax_t) 832 (object->un_pager.vnp.vnp_size >> 32), 833 (uintmax_t)object->un_pager.vnp.vnp_size); 834 } 835 vm_page_lock(m[i]); 836 vm_page_free(m[i]); 837 vm_page_unlock(m[i]); 838 VM_OBJECT_WUNLOCK(object); 839 runend = i + 1; 840 first = runend; 841 continue; 842 } 843 runend = i + runpg; 844 if (runend <= reqpage) { 845 VM_OBJECT_WLOCK(object); 846 for (j = i; j < runend; j++) { 847 vm_page_lock(m[j]); 848 vm_page_free(m[j]); 849 vm_page_unlock(m[j]); 850 } 851 VM_OBJECT_WUNLOCK(object); 852 } else { 853 if (runpg < (count - first)) { 854 VM_OBJECT_WLOCK(object); 855 for (i = first + runpg; i < count; i++) { 856 vm_page_lock(m[i]); 857 vm_page_free(m[i]); 858 vm_page_unlock(m[i]); 859 } 860 VM_OBJECT_WUNLOCK(object); 861 count = first + runpg; 862 } 863 break; 864 } 865 first = runend; 866 } 867 868 /* 869 * the first and last page have been calculated now, move input pages 870 * to be zero based... 871 */ 872 if (first != 0) { 873 m += first; 874 count -= first; 875 reqpage -= first; 876 } 877 878 /* 879 * calculate the file virtual address for the transfer 880 */ 881 foff = IDX_TO_OFF(m[0]->pindex); 882 883 /* 884 * calculate the size of the transfer 885 */ 886 size = count * PAGE_SIZE; 887 KASSERT(count > 0, ("zero count")); 888 if ((foff + size) > object->un_pager.vnp.vnp_size) 889 size = object->un_pager.vnp.vnp_size - foff; 890 KASSERT(size > 0, ("zero size")); 891 892 /* 893 * round up physical size for real devices. 894 */ 895 if (1) { 896 int secmask = bo->bo_bsize - 1; 897 KASSERT(secmask < PAGE_SIZE && secmask > 0, 898 ("vnode_pager_generic_getpages: sector size %d too large", 899 secmask + 1)); 900 size = (size + secmask) & ~secmask; 901 } 902 903 bp = getpbuf(&vnode_pbuf_freecnt); 904 kva = (vm_offset_t)bp->b_data; 905 906 /* 907 * and map the pages to be read into the kva, if the filesystem 908 * requires mapped buffers. 909 */ 910 mp = vp->v_mount; 911 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 912 unmapped_buf_allowed) { 913 bp->b_data = unmapped_buf; 914 bp->b_kvabase = unmapped_buf; 915 bp->b_offset = 0; 916 bp->b_flags |= B_UNMAPPED; 917 bp->b_npages = count; 918 for (i = 0; i < count; i++) 919 bp->b_pages[i] = m[i]; 920 } else 921 pmap_qenter(kva, m, count); 922 923 /* build a minimal buffer header */ 924 bp->b_iocmd = BIO_READ; 925 bp->b_iodone = bdone; 926 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 927 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 928 bp->b_rcred = crhold(curthread->td_ucred); 929 bp->b_wcred = crhold(curthread->td_ucred); 930 bp->b_blkno = firstaddr; 931 pbgetbo(bo, bp); 932 bp->b_vp = vp; 933 bp->b_bcount = size; 934 bp->b_bufsize = size; 935 bp->b_runningbufspace = bp->b_bufsize; 936 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 937 938 PCPU_INC(cnt.v_vnodein); 939 PCPU_ADD(cnt.v_vnodepgsin, count); 940 941 /* do the input */ 942 bp->b_iooffset = dbtob(bp->b_blkno); 943 bstrategy(bp); 944 945 bwait(bp, PVM, "vnread"); 946 947 if ((bp->b_ioflags & BIO_ERROR) != 0) 948 error = EIO; 949 950 if (error == 0 && size != count * PAGE_SIZE) { 951 if ((bp->b_flags & B_UNMAPPED) != 0) { 952 bp->b_flags &= ~B_UNMAPPED; 953 pmap_qenter(kva, m, count); 954 } 955 bzero((caddr_t)kva + size, PAGE_SIZE * count - size); 956 } 957 if ((bp->b_flags & B_UNMAPPED) == 0) 958 pmap_qremove(kva, count); 959 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0) { 960 bp->b_data = (caddr_t)kva; 961 bp->b_kvabase = (caddr_t)kva; 962 bp->b_flags &= ~B_UNMAPPED; 963 for (i = 0; i < count; i++) 964 bp->b_pages[i] = NULL; 965 } 966 967 /* 968 * free the buffer header back to the swap buffer pool 969 */ 970 bp->b_vp = NULL; 971 pbrelbo(bp); 972 relpbuf(bp, &vnode_pbuf_freecnt); 973 974 VM_OBJECT_WLOCK(object); 975 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 976 vm_page_t mt; 977 978 nextoff = tfoff + PAGE_SIZE; 979 mt = m[i]; 980 981 if (nextoff <= object->un_pager.vnp.vnp_size) { 982 /* 983 * Read filled up entire page. 984 */ 985 mt->valid = VM_PAGE_BITS_ALL; 986 KASSERT(mt->dirty == 0, 987 ("vnode_pager_generic_getpages: page %p is dirty", 988 mt)); 989 KASSERT(!pmap_page_is_mapped(mt), 990 ("vnode_pager_generic_getpages: page %p is mapped", 991 mt)); 992 } else { 993 /* 994 * Read did not fill up entire page. 995 * 996 * Currently we do not set the entire page valid, 997 * we just try to clear the piece that we couldn't 998 * read. 999 */ 1000 vm_page_set_valid_range(mt, 0, 1001 object->un_pager.vnp.vnp_size - tfoff); 1002 KASSERT((mt->dirty & vm_page_bits(0, 1003 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1004 ("vnode_pager_generic_getpages: page %p is dirty", 1005 mt)); 1006 } 1007 1008 if (i != reqpage) 1009 vm_page_readahead_finish(mt); 1010 } 1011 VM_OBJECT_WUNLOCK(object); 1012 if (error) { 1013 printf("vnode_pager_getpages: I/O read error\n"); 1014 } 1015 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 1016 } 1017 1018 /* 1019 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1020 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1021 * vnode_pager_generic_putpages() to implement the previous behaviour. 1022 * 1023 * All other FS's should use the bypass to get to the local media 1024 * backing vp's VOP_PUTPAGES. 1025 */ 1026 static void 1027 vnode_pager_putpages(object, m, count, sync, rtvals) 1028 vm_object_t object; 1029 vm_page_t *m; 1030 int count; 1031 boolean_t sync; 1032 int *rtvals; 1033 { 1034 int rtval; 1035 struct vnode *vp; 1036 int bytes = count * PAGE_SIZE; 1037 1038 /* 1039 * Force synchronous operation if we are extremely low on memory 1040 * to prevent a low-memory deadlock. VOP operations often need to 1041 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1042 * operation ). The swapper handles the case by limiting the amount 1043 * of asynchronous I/O, but that sort of solution doesn't scale well 1044 * for the vnode pager without a lot of work. 1045 * 1046 * Also, the backing vnode's iodone routine may not wake the pageout 1047 * daemon up. This should be probably be addressed XXX. 1048 */ 1049 1050 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 1051 sync |= OBJPC_SYNC; 1052 1053 /* 1054 * Call device-specific putpages function 1055 */ 1056 vp = object->handle; 1057 VM_OBJECT_WUNLOCK(object); 1058 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 1059 KASSERT(rtval != EOPNOTSUPP, 1060 ("vnode_pager: stale FS putpages\n")); 1061 VM_OBJECT_WLOCK(object); 1062 } 1063 1064 1065 /* 1066 * This is now called from local media FS's to operate against their 1067 * own vnodes if they fail to implement VOP_PUTPAGES. 1068 * 1069 * This is typically called indirectly via the pageout daemon and 1070 * clustering has already typically occured, so in general we ask the 1071 * underlying filesystem to write the data out asynchronously rather 1072 * then delayed. 1073 */ 1074 int 1075 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1076 int flags, int *rtvals) 1077 { 1078 int i; 1079 vm_object_t object; 1080 vm_page_t m; 1081 int count; 1082 1083 int maxsize, ncount; 1084 vm_ooffset_t poffset; 1085 struct uio auio; 1086 struct iovec aiov; 1087 int error; 1088 int ioflags; 1089 int ppscheck = 0; 1090 static struct timeval lastfail; 1091 static int curfail; 1092 1093 object = vp->v_object; 1094 count = bytecount / PAGE_SIZE; 1095 1096 for (i = 0; i < count; i++) 1097 rtvals[i] = VM_PAGER_ERROR; 1098 1099 if ((int64_t)ma[0]->pindex < 0) { 1100 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1101 (long)ma[0]->pindex, (u_long)ma[0]->dirty); 1102 rtvals[0] = VM_PAGER_BAD; 1103 return VM_PAGER_BAD; 1104 } 1105 1106 maxsize = count * PAGE_SIZE; 1107 ncount = count; 1108 1109 poffset = IDX_TO_OFF(ma[0]->pindex); 1110 1111 /* 1112 * If the page-aligned write is larger then the actual file we 1113 * have to invalidate pages occuring beyond the file EOF. However, 1114 * there is an edge case where a file may not be page-aligned where 1115 * the last page is partially invalid. In this case the filesystem 1116 * may not properly clear the dirty bits for the entire page (which 1117 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1118 * With the page locked we are free to fix-up the dirty bits here. 1119 * 1120 * We do not under any circumstances truncate the valid bits, as 1121 * this will screw up bogus page replacement. 1122 */ 1123 VM_OBJECT_WLOCK(object); 1124 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1125 if (object->un_pager.vnp.vnp_size > poffset) { 1126 int pgoff; 1127 1128 maxsize = object->un_pager.vnp.vnp_size - poffset; 1129 ncount = btoc(maxsize); 1130 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1131 /* 1132 * If the object is locked and the following 1133 * conditions hold, then the page's dirty 1134 * field cannot be concurrently changed by a 1135 * pmap operation. 1136 */ 1137 m = ma[ncount - 1]; 1138 vm_page_assert_sbusied(m); 1139 KASSERT(!pmap_page_is_write_mapped(m), 1140 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1141 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1142 pgoff); 1143 } 1144 } else { 1145 maxsize = 0; 1146 ncount = 0; 1147 } 1148 if (ncount < count) { 1149 for (i = ncount; i < count; i++) { 1150 rtvals[i] = VM_PAGER_BAD; 1151 } 1152 } 1153 } 1154 VM_OBJECT_WUNLOCK(object); 1155 1156 /* 1157 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 1158 * rather then a bdwrite() to prevent paging I/O from saturating 1159 * the buffer cache. Dummy-up the sequential heuristic to cause 1160 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1161 * the system decides how to cluster. 1162 */ 1163 ioflags = IO_VMIO; 1164 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1165 ioflags |= IO_SYNC; 1166 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1167 ioflags |= IO_ASYNC; 1168 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1169 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1170 1171 aiov.iov_base = (caddr_t) 0; 1172 aiov.iov_len = maxsize; 1173 auio.uio_iov = &aiov; 1174 auio.uio_iovcnt = 1; 1175 auio.uio_offset = poffset; 1176 auio.uio_segflg = UIO_NOCOPY; 1177 auio.uio_rw = UIO_WRITE; 1178 auio.uio_resid = maxsize; 1179 auio.uio_td = (struct thread *) 0; 1180 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1181 PCPU_INC(cnt.v_vnodeout); 1182 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1183 1184 if (error) { 1185 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1186 printf("vnode_pager_putpages: I/O error %d\n", error); 1187 } 1188 if (auio.uio_resid) { 1189 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1190 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1191 auio.uio_resid, (u_long)ma[0]->pindex); 1192 } 1193 for (i = 0; i < ncount; i++) { 1194 rtvals[i] = VM_PAGER_OK; 1195 } 1196 return rtvals[0]; 1197 } 1198 1199 void 1200 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1201 { 1202 vm_object_t obj; 1203 int i, pos; 1204 1205 if (written == 0) 1206 return; 1207 obj = ma[0]->object; 1208 VM_OBJECT_WLOCK(obj); 1209 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1210 if (pos < trunc_page(written)) { 1211 rtvals[i] = VM_PAGER_OK; 1212 vm_page_undirty(ma[i]); 1213 } else { 1214 /* Partially written page. */ 1215 rtvals[i] = VM_PAGER_AGAIN; 1216 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1217 } 1218 } 1219 VM_OBJECT_WUNLOCK(obj); 1220 } 1221 1222 void 1223 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1224 vm_offset_t end) 1225 { 1226 struct vnode *vp; 1227 vm_ooffset_t old_wm; 1228 1229 VM_OBJECT_WLOCK(object); 1230 if (object->type != OBJT_VNODE) { 1231 VM_OBJECT_WUNLOCK(object); 1232 return; 1233 } 1234 old_wm = object->un_pager.vnp.writemappings; 1235 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1236 vp = object->handle; 1237 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1238 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1239 VOP_ADD_WRITECOUNT(vp, 1); 1240 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1241 __func__, vp, vp->v_writecount); 1242 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1243 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1244 VOP_ADD_WRITECOUNT(vp, -1); 1245 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1246 __func__, vp, vp->v_writecount); 1247 } 1248 VM_OBJECT_WUNLOCK(object); 1249 } 1250 1251 void 1252 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1253 vm_offset_t end) 1254 { 1255 struct vnode *vp; 1256 struct mount *mp; 1257 vm_offset_t inc; 1258 1259 VM_OBJECT_WLOCK(object); 1260 1261 /* 1262 * First, recheck the object type to account for the race when 1263 * the vnode is reclaimed. 1264 */ 1265 if (object->type != OBJT_VNODE) { 1266 VM_OBJECT_WUNLOCK(object); 1267 return; 1268 } 1269 1270 /* 1271 * Optimize for the case when writemappings is not going to 1272 * zero. 1273 */ 1274 inc = end - start; 1275 if (object->un_pager.vnp.writemappings != inc) { 1276 object->un_pager.vnp.writemappings -= inc; 1277 VM_OBJECT_WUNLOCK(object); 1278 return; 1279 } 1280 1281 vp = object->handle; 1282 vhold(vp); 1283 VM_OBJECT_WUNLOCK(object); 1284 mp = NULL; 1285 vn_start_write(vp, &mp, V_WAIT); 1286 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1287 1288 /* 1289 * Decrement the object's writemappings, by swapping the start 1290 * and end arguments for vnode_pager_update_writecount(). If 1291 * there was not a race with vnode reclaimation, then the 1292 * vnode's v_writecount is decremented. 1293 */ 1294 vnode_pager_update_writecount(object, end, start); 1295 VOP_UNLOCK(vp, 0); 1296 vdrop(vp); 1297 if (mp != NULL) 1298 vn_finished_write(mp); 1299 }
Cache object: 5e800b3140a4629ef6490a902128d64d
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