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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/6.2/sys/vm/vnode_pager.c 163340 2006-10-14 06:04:32Z 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/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 daddr_t vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 79 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, vm_ooffset_t); 87 88 struct pagerops vnodepagerops = { 89 .pgo_alloc = vnode_pager_alloc, 90 .pgo_dealloc = vnode_pager_dealloc, 91 .pgo_getpages = vnode_pager_getpages, 92 .pgo_putpages = vnode_pager_putpages, 93 .pgo_haspage = vnode_pager_haspage, 94 }; 95 96 int vnode_pbuf_freecnt; 97 98 /* 99 * Compatibility function for RELENG_6, in which vnode_create_vobject() 100 * takes file size as size_t due to an oversight. The type may not just 101 * change to off_t because the ABI to 3rd party modules must be preserved 102 * for RELENG_6 lifetime. 103 */ 104 int 105 vnode_create_vobject(struct vnode *vp, size_t isize __unused, struct thread *td) 106 { 107 108 /* 109 * Size of 0 will indicate to vnode_create_vobject_off() 110 * VOP_GETATTR() is to be called to get the actual size. 111 */ 112 return (vnode_create_vobject_off(vp, 0, td)); 113 } 114 115 /* 116 * Create the VM system backing object for this vnode -- for RELENG_6 only. 117 * In HEAD, vnode_create_vobject() has been fixed to take file size as off_t 118 * and so it can be used as is. 119 */ 120 int 121 vnode_create_vobject_off(struct vnode *vp, off_t isize, struct thread *td) 122 { 123 vm_object_t object; 124 vm_ooffset_t size = isize; 125 struct vattr va; 126 127 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 128 return (0); 129 130 while ((object = vp->v_object) != NULL) { 131 VM_OBJECT_LOCK(object); 132 if (!(object->flags & OBJ_DEAD)) { 133 VM_OBJECT_UNLOCK(object); 134 return (0); 135 } 136 VOP_UNLOCK(vp, 0, td); 137 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 138 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0); 139 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 140 } 141 142 if (size == 0) { 143 if (vn_isdisk(vp, NULL)) { 144 size = IDX_TO_OFF(INT_MAX); 145 } else { 146 if (VOP_GETATTR(vp, &va, td->td_ucred, td) != 0) 147 return (0); 148 size = va.va_size; 149 } 150 } 151 152 object = vnode_pager_alloc(vp, size, 0, 0); 153 /* 154 * Dereference the reference we just created. This assumes 155 * that the object is associated with the vp. 156 */ 157 VM_OBJECT_LOCK(object); 158 object->ref_count--; 159 VM_OBJECT_UNLOCK(object); 160 vrele(vp); 161 162 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 163 164 return (0); 165 } 166 167 void 168 vnode_destroy_vobject(struct vnode *vp) 169 { 170 struct vm_object *obj; 171 172 obj = vp->v_object; 173 if (obj == NULL) 174 return; 175 ASSERT_VOP_LOCKED(vp, "vnode_destroy_vobject"); 176 VM_OBJECT_LOCK(obj); 177 if (obj->ref_count == 0) { 178 /* 179 * vclean() may be called twice. The first time 180 * removes the primary reference to the object, 181 * the second time goes one further and is a 182 * special-case to terminate the object. 183 * 184 * don't double-terminate the object 185 */ 186 if ((obj->flags & OBJ_DEAD) == 0) 187 vm_object_terminate(obj); 188 else 189 VM_OBJECT_UNLOCK(obj); 190 } else { 191 /* 192 * Woe to the process that tries to page now :-). 193 */ 194 vm_pager_deallocate(obj); 195 VM_OBJECT_UNLOCK(obj); 196 } 197 vp->v_object = NULL; 198 } 199 200 201 /* 202 * Allocate (or lookup) pager for a vnode. 203 * Handle is a vnode pointer. 204 * 205 * MPSAFE 206 */ 207 vm_object_t 208 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 209 vm_ooffset_t offset) 210 { 211 vm_object_t object; 212 struct vnode *vp; 213 214 /* 215 * Pageout to vnode, no can do yet. 216 */ 217 if (handle == NULL) 218 return (NULL); 219 220 vp = (struct vnode *) handle; 221 222 ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc"); 223 224 /* 225 * If the object is being terminated, wait for it to 226 * go away. 227 */ 228 while ((object = vp->v_object) != NULL) { 229 VM_OBJECT_LOCK(object); 230 if ((object->flags & OBJ_DEAD) == 0) 231 break; 232 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 233 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); 234 } 235 236 if (vp->v_usecount == 0) 237 panic("vnode_pager_alloc: no vnode reference"); 238 239 if (object == NULL) { 240 /* 241 * And an object of the appropriate size 242 */ 243 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 244 245 object->un_pager.vnp.vnp_size = size; 246 247 object->handle = handle; 248 if (VFS_NEEDSGIANT(vp->v_mount)) 249 vm_object_set_flag(object, OBJ_NEEDGIANT); 250 vp->v_object = object; 251 } else { 252 object->ref_count++; 253 VM_OBJECT_UNLOCK(object); 254 } 255 vref(vp); 256 return (object); 257 } 258 259 /* 260 * The object must be locked. 261 */ 262 static void 263 vnode_pager_dealloc(object) 264 vm_object_t object; 265 { 266 struct vnode *vp = object->handle; 267 268 if (vp == NULL) 269 panic("vnode_pager_dealloc: pager already dealloced"); 270 271 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 272 vm_object_pip_wait(object, "vnpdea"); 273 274 object->handle = NULL; 275 object->type = OBJT_DEAD; 276 if (object->flags & OBJ_DISCONNECTWNT) { 277 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 278 wakeup(object); 279 } 280 ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc"); 281 vp->v_object = NULL; 282 vp->v_vflag &= ~VV_TEXT; 283 } 284 285 static boolean_t 286 vnode_pager_haspage(object, pindex, before, after) 287 vm_object_t object; 288 vm_pindex_t pindex; 289 int *before; 290 int *after; 291 { 292 struct vnode *vp = object->handle; 293 daddr_t bn; 294 int err; 295 daddr_t reqblock; 296 int poff; 297 int bsize; 298 int pagesperblock, blocksperpage; 299 int vfslocked; 300 301 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 302 /* 303 * If no vp or vp is doomed or marked transparent to VM, we do not 304 * have the page. 305 */ 306 if (vp == NULL || vp->v_iflag & VI_DOOMED) 307 return FALSE; 308 /* 309 * If the offset is beyond end of file we do 310 * not have the page. 311 */ 312 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 313 return FALSE; 314 315 bsize = vp->v_mount->mnt_stat.f_iosize; 316 pagesperblock = bsize / PAGE_SIZE; 317 blocksperpage = 0; 318 if (pagesperblock > 0) { 319 reqblock = pindex / pagesperblock; 320 } else { 321 blocksperpage = (PAGE_SIZE / bsize); 322 reqblock = pindex * blocksperpage; 323 } 324 VM_OBJECT_UNLOCK(object); 325 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 326 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 327 VFS_UNLOCK_GIANT(vfslocked); 328 VM_OBJECT_LOCK(object); 329 if (err) 330 return TRUE; 331 if (bn == -1) 332 return FALSE; 333 if (pagesperblock > 0) { 334 poff = pindex - (reqblock * pagesperblock); 335 if (before) { 336 *before *= pagesperblock; 337 *before += poff; 338 } 339 if (after) { 340 int numafter; 341 *after *= pagesperblock; 342 numafter = pagesperblock - (poff + 1); 343 if (IDX_TO_OFF(pindex + numafter) > 344 object->un_pager.vnp.vnp_size) { 345 numafter = 346 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 347 pindex; 348 } 349 *after += numafter; 350 } 351 } else { 352 if (before) { 353 *before /= blocksperpage; 354 } 355 356 if (after) { 357 *after /= blocksperpage; 358 } 359 } 360 return TRUE; 361 } 362 363 /* 364 * Lets the VM system know about a change in size for a file. 365 * We adjust our own internal size and flush any cached pages in 366 * the associated object that are affected by the size change. 367 * 368 * Note: this routine may be invoked as a result of a pager put 369 * operation (possibly at object termination time), so we must be careful. 370 */ 371 void 372 vnode_pager_setsize(vp, nsize) 373 struct vnode *vp; 374 vm_ooffset_t nsize; 375 { 376 vm_object_t object; 377 vm_page_t m; 378 vm_pindex_t nobjsize; 379 380 if ((object = vp->v_object) == NULL) 381 return; 382 VM_OBJECT_LOCK(object); 383 if (nsize == object->un_pager.vnp.vnp_size) { 384 /* 385 * Hasn't changed size 386 */ 387 VM_OBJECT_UNLOCK(object); 388 return; 389 } 390 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 391 if (nsize < object->un_pager.vnp.vnp_size) { 392 /* 393 * File has shrunk. Toss any cached pages beyond the new EOF. 394 */ 395 if (nobjsize < object->size) 396 vm_object_page_remove(object, nobjsize, object->size, 397 FALSE); 398 /* 399 * this gets rid of garbage at the end of a page that is now 400 * only partially backed by the vnode. 401 * 402 * XXX for some reason (I don't know yet), if we take a 403 * completely invalid page and mark it partially valid 404 * it can screw up NFS reads, so we don't allow the case. 405 */ 406 if ((nsize & PAGE_MASK) && 407 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 408 m->valid != 0) { 409 int base = (int)nsize & PAGE_MASK; 410 int size = PAGE_SIZE - base; 411 412 /* 413 * Clear out partial-page garbage in case 414 * the page has been mapped. 415 */ 416 pmap_zero_page_area(m, base, size); 417 418 /* 419 * XXX work around SMP data integrity race 420 * by unmapping the page from user processes. 421 * The garbage we just cleared may be mapped 422 * to a user process running on another cpu 423 * and this code is not running through normal 424 * I/O channels which handle SMP issues for 425 * us, so unmap page to synchronize all cpus. 426 * 427 * XXX should vm_pager_unmap_page() have 428 * dealt with this? 429 */ 430 vm_page_lock_queues(); 431 pmap_remove_all(m); 432 433 /* 434 * Clear out partial-page dirty bits. This 435 * has the side effect of setting the valid 436 * bits, but that is ok. There are a bunch 437 * of places in the VM system where we expected 438 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 439 * case is one of them. If the page is still 440 * partially dirty, make it fully dirty. 441 * 442 * note that we do not clear out the valid 443 * bits. This would prevent bogus_page 444 * replacement from working properly. 445 */ 446 vm_page_set_validclean(m, base, size); 447 if (m->dirty != 0) 448 m->dirty = VM_PAGE_BITS_ALL; 449 vm_page_unlock_queues(); 450 } 451 } 452 object->un_pager.vnp.vnp_size = nsize; 453 object->size = nobjsize; 454 VM_OBJECT_UNLOCK(object); 455 } 456 457 /* 458 * calculate the linear (byte) disk address of specified virtual 459 * file address 460 */ 461 static daddr_t 462 vnode_pager_addr(vp, address, run) 463 struct vnode *vp; 464 vm_ooffset_t address; 465 int *run; 466 { 467 daddr_t rtaddress; 468 int bsize; 469 daddr_t block; 470 int err; 471 daddr_t vblock; 472 daddr_t voffset; 473 474 if (address < 0) 475 return -1; 476 477 if (vp->v_iflag & VI_DOOMED) 478 return -1; 479 480 bsize = vp->v_mount->mnt_stat.f_iosize; 481 vblock = address / bsize; 482 voffset = address % bsize; 483 484 err = VOP_BMAP(vp, vblock, NULL, &block, run, NULL); 485 486 if (err || (block == -1)) 487 rtaddress = -1; 488 else { 489 rtaddress = block + voffset / DEV_BSIZE; 490 if (run) { 491 *run += 1; 492 *run *= bsize/PAGE_SIZE; 493 *run -= voffset/PAGE_SIZE; 494 } 495 } 496 497 return rtaddress; 498 } 499 500 /* 501 * small block filesystem vnode pager input 502 */ 503 static int 504 vnode_pager_input_smlfs(object, m) 505 vm_object_t object; 506 vm_page_t m; 507 { 508 int i; 509 struct vnode *vp; 510 struct bufobj *bo; 511 struct buf *bp; 512 struct sf_buf *sf; 513 daddr_t fileaddr; 514 vm_offset_t bsize; 515 int error = 0; 516 517 vp = object->handle; 518 if (vp->v_iflag & VI_DOOMED) 519 return VM_PAGER_BAD; 520 521 bsize = vp->v_mount->mnt_stat.f_iosize; 522 523 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 524 525 sf = sf_buf_alloc(m, 0); 526 527 for (i = 0; i < PAGE_SIZE / bsize; i++) { 528 vm_ooffset_t address; 529 530 if (vm_page_bits(i * bsize, bsize) & m->valid) 531 continue; 532 533 address = IDX_TO_OFF(m->pindex) + i * bsize; 534 if (address >= object->un_pager.vnp.vnp_size) { 535 fileaddr = -1; 536 } else { 537 fileaddr = vnode_pager_addr(vp, address, NULL); 538 } 539 if (fileaddr != -1) { 540 bp = getpbuf(&vnode_pbuf_freecnt); 541 542 /* build a minimal buffer header */ 543 bp->b_iocmd = BIO_READ; 544 bp->b_iodone = bdone; 545 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 546 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 547 bp->b_rcred = crhold(curthread->td_ucred); 548 bp->b_wcred = crhold(curthread->td_ucred); 549 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 550 bp->b_blkno = fileaddr; 551 pbgetbo(bo, bp); 552 bp->b_bcount = bsize; 553 bp->b_bufsize = bsize; 554 bp->b_runningbufspace = bp->b_bufsize; 555 atomic_add_int(&runningbufspace, bp->b_runningbufspace); 556 557 /* do the input */ 558 bp->b_iooffset = dbtob(bp->b_blkno); 559 bstrategy(bp); 560 561 bwait(bp, PVM, "vnsrd"); 562 563 if ((bp->b_ioflags & BIO_ERROR) != 0) 564 error = EIO; 565 566 /* 567 * free the buffer header back to the swap buffer pool 568 */ 569 pbrelbo(bp); 570 relpbuf(bp, &vnode_pbuf_freecnt); 571 if (error) 572 break; 573 574 VM_OBJECT_LOCK(object); 575 vm_page_lock_queues(); 576 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 577 vm_page_unlock_queues(); 578 VM_OBJECT_UNLOCK(object); 579 } else { 580 VM_OBJECT_LOCK(object); 581 vm_page_lock_queues(); 582 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 583 vm_page_unlock_queues(); 584 VM_OBJECT_UNLOCK(object); 585 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 586 } 587 } 588 sf_buf_free(sf); 589 vm_page_lock_queues(); 590 pmap_clear_modify(m); 591 vm_page_unlock_queues(); 592 if (error) { 593 return VM_PAGER_ERROR; 594 } 595 return VM_PAGER_OK; 596 597 } 598 599 600 /* 601 * old style vnode pager input routine 602 */ 603 static int 604 vnode_pager_input_old(object, m) 605 vm_object_t object; 606 vm_page_t m; 607 { 608 struct uio auio; 609 struct iovec aiov; 610 int error; 611 int size; 612 struct sf_buf *sf; 613 struct vnode *vp; 614 615 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 616 error = 0; 617 618 /* 619 * Return failure if beyond current EOF 620 */ 621 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 622 return VM_PAGER_BAD; 623 } else { 624 size = PAGE_SIZE; 625 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 626 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 627 vp = object->handle; 628 VM_OBJECT_UNLOCK(object); 629 630 /* 631 * Allocate a kernel virtual address and initialize so that 632 * we can use VOP_READ/WRITE routines. 633 */ 634 sf = sf_buf_alloc(m, 0); 635 636 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 637 aiov.iov_len = size; 638 auio.uio_iov = &aiov; 639 auio.uio_iovcnt = 1; 640 auio.uio_offset = IDX_TO_OFF(m->pindex); 641 auio.uio_segflg = UIO_SYSSPACE; 642 auio.uio_rw = UIO_READ; 643 auio.uio_resid = size; 644 auio.uio_td = curthread; 645 646 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 647 if (!error) { 648 int count = size - auio.uio_resid; 649 650 if (count == 0) 651 error = EINVAL; 652 else if (count != PAGE_SIZE) 653 bzero((caddr_t)sf_buf_kva(sf) + count, 654 PAGE_SIZE - count); 655 } 656 sf_buf_free(sf); 657 658 VM_OBJECT_LOCK(object); 659 } 660 vm_page_lock_queues(); 661 pmap_clear_modify(m); 662 vm_page_undirty(m); 663 vm_page_unlock_queues(); 664 if (!error) 665 m->valid = VM_PAGE_BITS_ALL; 666 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 667 } 668 669 /* 670 * generic vnode pager input routine 671 */ 672 673 /* 674 * Local media VFS's that do not implement their own VOP_GETPAGES 675 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 676 * to implement the previous behaviour. 677 * 678 * All other FS's should use the bypass to get to the local media 679 * backing vp's VOP_GETPAGES. 680 */ 681 static int 682 vnode_pager_getpages(object, m, count, reqpage) 683 vm_object_t object; 684 vm_page_t *m; 685 int count; 686 int reqpage; 687 { 688 int rtval; 689 struct vnode *vp; 690 int bytes = count * PAGE_SIZE; 691 int vfslocked; 692 693 vp = object->handle; 694 VM_OBJECT_UNLOCK(object); 695 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 696 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 697 KASSERT(rtval != EOPNOTSUPP, 698 ("vnode_pager: FS getpages not implemented\n")); 699 VFS_UNLOCK_GIANT(vfslocked); 700 VM_OBJECT_LOCK(object); 701 return rtval; 702 } 703 704 /* 705 * This is now called from local media FS's to operate against their 706 * own vnodes if they fail to implement VOP_GETPAGES. 707 */ 708 int 709 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 710 struct vnode *vp; 711 vm_page_t *m; 712 int bytecount; 713 int reqpage; 714 { 715 vm_object_t object; 716 vm_offset_t kva; 717 off_t foff, tfoff, nextoff; 718 int i, j, size, bsize, first; 719 daddr_t firstaddr, reqblock; 720 struct bufobj *bo; 721 int runpg; 722 int runend; 723 struct buf *bp; 724 int count; 725 int error = 0; 726 727 object = vp->v_object; 728 count = bytecount / PAGE_SIZE; 729 730 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 731 ("vnode_pager_generic_getpages does not support devices")); 732 if (vp->v_iflag & VI_DOOMED) 733 return VM_PAGER_BAD; 734 735 bsize = vp->v_mount->mnt_stat.f_iosize; 736 737 /* get the UNDERLYING device for the file with VOP_BMAP() */ 738 739 /* 740 * originally, we did not check for an error return value -- assuming 741 * an fs always has a bmap entry point -- that assumption is wrong!!! 742 */ 743 foff = IDX_TO_OFF(m[reqpage]->pindex); 744 745 /* 746 * if we can't bmap, use old VOP code 747 */ 748 if (VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL)) { 749 VM_OBJECT_LOCK(object); 750 vm_page_lock_queues(); 751 for (i = 0; i < count; i++) 752 if (i != reqpage) 753 vm_page_free(m[i]); 754 vm_page_unlock_queues(); 755 cnt.v_vnodein++; 756 cnt.v_vnodepgsin++; 757 error = vnode_pager_input_old(object, m[reqpage]); 758 VM_OBJECT_UNLOCK(object); 759 return (error); 760 761 /* 762 * if the blocksize is smaller than a page size, then use 763 * special small filesystem code. NFS sometimes has a small 764 * blocksize, but it can handle large reads itself. 765 */ 766 } else if ((PAGE_SIZE / bsize) > 1 && 767 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 768 VM_OBJECT_LOCK(object); 769 vm_page_lock_queues(); 770 for (i = 0; i < count; i++) 771 if (i != reqpage) 772 vm_page_free(m[i]); 773 vm_page_unlock_queues(); 774 VM_OBJECT_UNLOCK(object); 775 cnt.v_vnodein++; 776 cnt.v_vnodepgsin++; 777 return vnode_pager_input_smlfs(object, m[reqpage]); 778 } 779 780 /* 781 * If we have a completely valid page available to us, we can 782 * clean up and return. Otherwise we have to re-read the 783 * media. 784 */ 785 VM_OBJECT_LOCK(object); 786 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 787 vm_page_lock_queues(); 788 for (i = 0; i < count; i++) 789 if (i != reqpage) 790 vm_page_free(m[i]); 791 vm_page_unlock_queues(); 792 VM_OBJECT_UNLOCK(object); 793 return VM_PAGER_OK; 794 } else if (reqblock == -1) { 795 pmap_zero_page(m[reqpage]); 796 vm_page_undirty(m[reqpage]); 797 m[reqpage]->valid = VM_PAGE_BITS_ALL; 798 vm_page_lock_queues(); 799 for (i = 0; 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_OK); 805 } 806 m[reqpage]->valid = 0; 807 VM_OBJECT_UNLOCK(object); 808 809 /* 810 * here on direct device I/O 811 */ 812 firstaddr = -1; 813 814 /* 815 * calculate the run that includes the required page 816 */ 817 for (first = 0, i = 0; i < count; i = runend) { 818 firstaddr = vnode_pager_addr(vp, 819 IDX_TO_OFF(m[i]->pindex), &runpg); 820 if (firstaddr == -1) { 821 VM_OBJECT_LOCK(object); 822 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 823 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 824 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 825 (uintmax_t)foff, 826 (uintmax_t) 827 (object->un_pager.vnp.vnp_size >> 32), 828 (uintmax_t)object->un_pager.vnp.vnp_size); 829 } 830 vm_page_lock_queues(); 831 vm_page_free(m[i]); 832 vm_page_unlock_queues(); 833 VM_OBJECT_UNLOCK(object); 834 runend = i + 1; 835 first = runend; 836 continue; 837 } 838 runend = i + runpg; 839 if (runend <= reqpage) { 840 VM_OBJECT_LOCK(object); 841 vm_page_lock_queues(); 842 for (j = i; j < runend; j++) 843 vm_page_free(m[j]); 844 vm_page_unlock_queues(); 845 VM_OBJECT_UNLOCK(object); 846 } else { 847 if (runpg < (count - first)) { 848 VM_OBJECT_LOCK(object); 849 vm_page_lock_queues(); 850 for (i = first + runpg; i < count; i++) 851 vm_page_free(m[i]); 852 vm_page_unlock_queues(); 853 VM_OBJECT_UNLOCK(object); 854 count = first + runpg; 855 } 856 break; 857 } 858 first = runend; 859 } 860 861 /* 862 * the first and last page have been calculated now, move input pages 863 * to be zero based... 864 */ 865 if (first != 0) { 866 for (i = first; i < count; i++) { 867 m[i - first] = m[i]; 868 } 869 count -= first; 870 reqpage -= first; 871 } 872 873 /* 874 * calculate the file virtual address for the transfer 875 */ 876 foff = IDX_TO_OFF(m[0]->pindex); 877 878 /* 879 * calculate the size of the transfer 880 */ 881 size = count * PAGE_SIZE; 882 KASSERT(count > 0, ("zero count")); 883 if ((foff + size) > object->un_pager.vnp.vnp_size) 884 size = object->un_pager.vnp.vnp_size - foff; 885 KASSERT(size > 0, ("zero size")); 886 887 /* 888 * round up physical size for real devices. 889 */ 890 if (1) { 891 int secmask = bo->bo_bsize - 1; 892 KASSERT(secmask < PAGE_SIZE && secmask > 0, 893 ("vnode_pager_generic_getpages: sector size %d too large", 894 secmask + 1)); 895 size = (size + secmask) & ~secmask; 896 } 897 898 bp = getpbuf(&vnode_pbuf_freecnt); 899 kva = (vm_offset_t) bp->b_data; 900 901 /* 902 * and map the pages to be read into the kva 903 */ 904 pmap_qenter(kva, m, count); 905 906 /* build a minimal buffer header */ 907 bp->b_iocmd = BIO_READ; 908 bp->b_iodone = bdone; 909 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 910 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 911 bp->b_rcred = crhold(curthread->td_ucred); 912 bp->b_wcred = crhold(curthread->td_ucred); 913 bp->b_blkno = firstaddr; 914 pbgetbo(bo, bp); 915 bp->b_bcount = size; 916 bp->b_bufsize = size; 917 bp->b_runningbufspace = bp->b_bufsize; 918 atomic_add_int(&runningbufspace, bp->b_runningbufspace); 919 920 cnt.v_vnodein++; 921 cnt.v_vnodepgsin += count; 922 923 /* do the input */ 924 bp->b_iooffset = dbtob(bp->b_blkno); 925 bstrategy(bp); 926 927 bwait(bp, PVM, "vnread"); 928 929 if ((bp->b_ioflags & BIO_ERROR) != 0) 930 error = EIO; 931 932 if (!error) { 933 if (size != count * PAGE_SIZE) 934 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 935 } 936 pmap_qremove(kva, count); 937 938 /* 939 * free the buffer header back to the swap buffer pool 940 */ 941 pbrelbo(bp); 942 relpbuf(bp, &vnode_pbuf_freecnt); 943 944 VM_OBJECT_LOCK(object); 945 vm_page_lock_queues(); 946 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 947 vm_page_t mt; 948 949 nextoff = tfoff + PAGE_SIZE; 950 mt = m[i]; 951 952 if (nextoff <= object->un_pager.vnp.vnp_size) { 953 /* 954 * Read filled up entire page. 955 */ 956 mt->valid = VM_PAGE_BITS_ALL; 957 vm_page_undirty(mt); /* should be an assert? XXX */ 958 pmap_clear_modify(mt); 959 } else { 960 /* 961 * Read did not fill up entire page. Since this 962 * is getpages, the page may be mapped, so we have 963 * to zero the invalid portions of the page even 964 * though we aren't setting them valid. 965 * 966 * Currently we do not set the entire page valid, 967 * we just try to clear the piece that we couldn't 968 * read. 969 */ 970 vm_page_set_validclean(mt, 0, 971 object->un_pager.vnp.vnp_size - tfoff); 972 /* handled by vm_fault now */ 973 /* vm_page_zero_invalid(mt, FALSE); */ 974 } 975 976 if (i != reqpage) { 977 978 /* 979 * whether or not to leave the page activated is up in 980 * the air, but we should put the page on a page queue 981 * somewhere. (it already is in the object). Result: 982 * It appears that empirical results show that 983 * deactivating pages is best. 984 */ 985 986 /* 987 * just in case someone was asking for this page we 988 * now tell them that it is ok to use 989 */ 990 if (!error) { 991 if (mt->flags & PG_WANTED) 992 vm_page_activate(mt); 993 else 994 vm_page_deactivate(mt); 995 vm_page_wakeup(mt); 996 } else { 997 vm_page_free(mt); 998 } 999 } 1000 } 1001 vm_page_unlock_queues(); 1002 VM_OBJECT_UNLOCK(object); 1003 if (error) { 1004 printf("vnode_pager_getpages: I/O read error\n"); 1005 } 1006 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 1007 } 1008 1009 /* 1010 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1011 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1012 * vnode_pager_generic_putpages() to implement the previous behaviour. 1013 * 1014 * All other FS's should use the bypass to get to the local media 1015 * backing vp's VOP_PUTPAGES. 1016 */ 1017 static void 1018 vnode_pager_putpages(object, m, count, sync, rtvals) 1019 vm_object_t object; 1020 vm_page_t *m; 1021 int count; 1022 boolean_t sync; 1023 int *rtvals; 1024 { 1025 int rtval; 1026 struct vnode *vp; 1027 struct mount *mp; 1028 int bytes = count * PAGE_SIZE; 1029 1030 /* 1031 * Force synchronous operation if we are extremely low on memory 1032 * to prevent a low-memory deadlock. VOP operations often need to 1033 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1034 * operation ). The swapper handles the case by limiting the amount 1035 * of asynchronous I/O, but that sort of solution doesn't scale well 1036 * for the vnode pager without a lot of work. 1037 * 1038 * Also, the backing vnode's iodone routine may not wake the pageout 1039 * daemon up. This should be probably be addressed XXX. 1040 */ 1041 1042 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 1043 sync |= OBJPC_SYNC; 1044 1045 /* 1046 * Call device-specific putpages function 1047 */ 1048 vp = object->handle; 1049 VM_OBJECT_UNLOCK(object); 1050 if (vp->v_type != VREG) 1051 mp = NULL; 1052 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 1053 KASSERT(rtval != EOPNOTSUPP, 1054 ("vnode_pager: stale FS putpages\n")); 1055 VM_OBJECT_LOCK(object); 1056 } 1057 1058 1059 /* 1060 * This is now called from local media FS's to operate against their 1061 * own vnodes if they fail to implement VOP_PUTPAGES. 1062 * 1063 * This is typically called indirectly via the pageout daemon and 1064 * clustering has already typically occured, so in general we ask the 1065 * underlying filesystem to write the data out asynchronously rather 1066 * then delayed. 1067 */ 1068 int 1069 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) 1070 struct vnode *vp; 1071 vm_page_t *m; 1072 int bytecount; 1073 int flags; 1074 int *rtvals; 1075 { 1076 int i; 1077 vm_object_t object; 1078 int count; 1079 1080 int maxsize, ncount; 1081 vm_ooffset_t poffset; 1082 struct uio auio; 1083 struct iovec aiov; 1084 int error; 1085 int ioflags; 1086 int ppscheck = 0; 1087 static struct timeval lastfail; 1088 static int curfail; 1089 1090 object = vp->v_object; 1091 count = bytecount / PAGE_SIZE; 1092 1093 for (i = 0; i < count; i++) 1094 rtvals[i] = VM_PAGER_AGAIN; 1095 1096 if ((int64_t)m[0]->pindex < 0) { 1097 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1098 (long)m[0]->pindex, (u_long)m[0]->dirty); 1099 rtvals[0] = VM_PAGER_BAD; 1100 return VM_PAGER_BAD; 1101 } 1102 1103 maxsize = count * PAGE_SIZE; 1104 ncount = count; 1105 1106 poffset = IDX_TO_OFF(m[0]->pindex); 1107 1108 /* 1109 * If the page-aligned write is larger then the actual file we 1110 * have to invalidate pages occuring beyond the file EOF. However, 1111 * there is an edge case where a file may not be page-aligned where 1112 * the last page is partially invalid. In this case the filesystem 1113 * may not properly clear the dirty bits for the entire page (which 1114 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1115 * With the page locked we are free to fix-up the dirty bits here. 1116 * 1117 * We do not under any circumstances truncate the valid bits, as 1118 * this will screw up bogus page replacement. 1119 */ 1120 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1121 if (object->un_pager.vnp.vnp_size > poffset) { 1122 int pgoff; 1123 1124 maxsize = object->un_pager.vnp.vnp_size - poffset; 1125 ncount = btoc(maxsize); 1126 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1127 vm_page_lock_queues(); 1128 vm_page_clear_dirty(m[ncount - 1], pgoff, 1129 PAGE_SIZE - pgoff); 1130 vm_page_unlock_queues(); 1131 } 1132 } else { 1133 maxsize = 0; 1134 ncount = 0; 1135 } 1136 if (ncount < count) { 1137 for (i = ncount; i < count; i++) { 1138 rtvals[i] = VM_PAGER_BAD; 1139 } 1140 } 1141 } 1142 1143 /* 1144 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1145 * rather then a bdwrite() to prevent paging I/O from saturating 1146 * the buffer cache. Dummy-up the sequential heuristic to cause 1147 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1148 * the system decides how to cluster. 1149 */ 1150 ioflags = IO_VMIO; 1151 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1152 ioflags |= IO_SYNC; 1153 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1154 ioflags |= IO_ASYNC; 1155 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1156 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1157 1158 aiov.iov_base = (caddr_t) 0; 1159 aiov.iov_len = maxsize; 1160 auio.uio_iov = &aiov; 1161 auio.uio_iovcnt = 1; 1162 auio.uio_offset = poffset; 1163 auio.uio_segflg = UIO_NOCOPY; 1164 auio.uio_rw = UIO_WRITE; 1165 auio.uio_resid = maxsize; 1166 auio.uio_td = (struct thread *) 0; 1167 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1168 cnt.v_vnodeout++; 1169 cnt.v_vnodepgsout += ncount; 1170 1171 if (error) { 1172 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1173 printf("vnode_pager_putpages: I/O error %d\n", error); 1174 } 1175 if (auio.uio_resid) { 1176 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1177 printf("vnode_pager_putpages: residual I/O %d at %lu\n", 1178 auio.uio_resid, (u_long)m[0]->pindex); 1179 } 1180 for (i = 0; i < ncount; i++) { 1181 rtvals[i] = VM_PAGER_OK; 1182 } 1183 return rtvals[0]; 1184 } 1185 1186 struct vnode * 1187 vnode_pager_lock(vm_object_t first_object) 1188 { 1189 struct vnode *vp; 1190 vm_object_t backing_object, object; 1191 1192 VM_OBJECT_LOCK_ASSERT(first_object, MA_OWNED); 1193 for (object = first_object; object != NULL; object = backing_object) { 1194 if (object->type != OBJT_VNODE) { 1195 if ((backing_object = object->backing_object) != NULL) 1196 VM_OBJECT_LOCK(backing_object); 1197 if (object != first_object) 1198 VM_OBJECT_UNLOCK(object); 1199 continue; 1200 } 1201 retry: 1202 if (object->flags & OBJ_DEAD) { 1203 if (object != first_object) 1204 VM_OBJECT_UNLOCK(object); 1205 return NULL; 1206 } 1207 vp = object->handle; 1208 VI_LOCK(vp); 1209 VM_OBJECT_UNLOCK(object); 1210 if (first_object != object) 1211 VM_OBJECT_UNLOCK(first_object); 1212 VFS_ASSERT_GIANT(vp->v_mount); 1213 if (vget(vp, LK_CANRECURSE | LK_INTERLOCK | 1214 LK_RETRY | LK_SHARED, curthread)) { 1215 VM_OBJECT_LOCK(first_object); 1216 if (object != first_object) 1217 VM_OBJECT_LOCK(object); 1218 if (object->type != OBJT_VNODE) { 1219 if (object != first_object) 1220 VM_OBJECT_UNLOCK(object); 1221 return NULL; 1222 } 1223 printf("vnode_pager_lock: retrying\n"); 1224 goto retry; 1225 } 1226 VM_OBJECT_LOCK(first_object); 1227 return (vp); 1228 } 1229 return NULL; 1230 }
Cache object: fad02ae144fde8d2c41f743837643ee8
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