Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/vm/vnode_pager.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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/6.0/sys/vm/vnode_pager.c 149085 2005-08-15 14:04:47Z kan $"); 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 /* Create the VM system backing object for this vnode */ 99 int 100 vnode_create_vobject(struct vnode *vp, size_t isize, struct thread *td) 101 { 102 vm_object_t object; 103 vm_ooffset_t size = isize; 104 struct vattr va; 105 106 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 107 return (0); 108 109 while ((object = vp->v_object) != NULL) { 110 VM_OBJECT_LOCK(object); 111 if (!(object->flags & OBJ_DEAD)) { 112 VM_OBJECT_UNLOCK(object); 113 return (0); 114 } 115 VOP_UNLOCK(vp, 0, td); 116 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 117 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0); 118 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 119 } 120 121 if (size == 0) { 122 if (vn_isdisk(vp, NULL)) { 123 size = IDX_TO_OFF(INT_MAX); 124 } else { 125 if (VOP_GETATTR(vp, &va, td->td_ucred, td) != 0) 126 return (0); 127 size = va.va_size; 128 } 129 } 130 131 object = vnode_pager_alloc(vp, size, 0, 0); 132 /* 133 * Dereference the reference we just created. This assumes 134 * that the object is associated with the vp. 135 */ 136 VM_OBJECT_LOCK(object); 137 object->ref_count--; 138 VM_OBJECT_UNLOCK(object); 139 vrele(vp); 140 141 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 142 143 return (0); 144 } 145 146 void 147 vnode_destroy_vobject(struct vnode *vp) 148 { 149 struct vm_object *obj; 150 151 obj = vp->v_object; 152 if (obj == NULL) 153 return; 154 ASSERT_VOP_LOCKED(vp, "vnode_destroy_vobject"); 155 VM_OBJECT_LOCK(obj); 156 if (obj->ref_count == 0) { 157 /* 158 * vclean() may be called twice. The first time 159 * removes the primary reference to the object, 160 * the second time goes one further and is a 161 * special-case to terminate the object. 162 * 163 * don't double-terminate the object 164 */ 165 if ((obj->flags & OBJ_DEAD) == 0) 166 vm_object_terminate(obj); 167 else 168 VM_OBJECT_UNLOCK(obj); 169 } else { 170 /* 171 * Woe to the process that tries to page now :-). 172 */ 173 vm_pager_deallocate(obj); 174 VM_OBJECT_UNLOCK(obj); 175 } 176 vp->v_object = NULL; 177 } 178 179 180 /* 181 * Allocate (or lookup) pager for a vnode. 182 * Handle is a vnode pointer. 183 * 184 * MPSAFE 185 */ 186 vm_object_t 187 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 188 vm_ooffset_t offset) 189 { 190 vm_object_t object; 191 struct vnode *vp; 192 193 /* 194 * Pageout to vnode, no can do yet. 195 */ 196 if (handle == NULL) 197 return (NULL); 198 199 vp = (struct vnode *) handle; 200 201 ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc"); 202 203 /* 204 * If the object is being terminated, wait for it to 205 * go away. 206 */ 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 * And 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 if (VFS_NEEDSGIANT(vp->v_mount)) 228 vm_object_set_flag(object, OBJ_NEEDGIANT); 229 vp->v_object = object; 230 } else { 231 object->ref_count++; 232 VM_OBJECT_UNLOCK(object); 233 } 234 vref(vp); 235 return (object); 236 } 237 238 /* 239 * The object must be locked. 240 */ 241 static void 242 vnode_pager_dealloc(object) 243 vm_object_t object; 244 { 245 struct vnode *vp = object->handle; 246 247 if (vp == NULL) 248 panic("vnode_pager_dealloc: pager already dealloced"); 249 250 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 251 vm_object_pip_wait(object, "vnpdea"); 252 253 object->handle = NULL; 254 object->type = OBJT_DEAD; 255 if (object->flags & OBJ_DISCONNECTWNT) { 256 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 257 wakeup(object); 258 } 259 ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc"); 260 vp->v_object = NULL; 261 vp->v_vflag &= ~VV_TEXT; 262 } 263 264 static boolean_t 265 vnode_pager_haspage(object, pindex, before, after) 266 vm_object_t object; 267 vm_pindex_t pindex; 268 int *before; 269 int *after; 270 { 271 struct vnode *vp = object->handle; 272 daddr_t bn; 273 int err; 274 daddr_t reqblock; 275 int poff; 276 int bsize; 277 int pagesperblock, blocksperpage; 278 int vfslocked; 279 280 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 281 /* 282 * If no vp or vp is doomed or marked transparent to VM, we do not 283 * have the page. 284 */ 285 if (vp == NULL) 286 return FALSE; 287 288 VI_LOCK(vp); 289 if (vp->v_iflag & VI_DOOMED) { 290 VI_UNLOCK(vp); 291 return FALSE; 292 } 293 VI_UNLOCK(vp); 294 /* 295 * If filesystem no longer mounted or offset beyond end of file we do 296 * not have the page. 297 */ 298 if ((vp->v_mount == NULL) || 299 (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 VM_OBJECT_LOCK(object); 370 if (nsize == object->un_pager.vnp.vnp_size) { 371 /* 372 * Hasn't changed size 373 */ 374 VM_OBJECT_UNLOCK(object); 375 return; 376 } 377 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 378 if (nsize < object->un_pager.vnp.vnp_size) { 379 /* 380 * File has shrunk. Toss any cached pages beyond the new EOF. 381 */ 382 if (nobjsize < object->size) 383 vm_object_page_remove(object, nobjsize, object->size, 384 FALSE); 385 /* 386 * this gets rid of garbage at the end of a page that is now 387 * only partially backed by the vnode. 388 * 389 * XXX for some reason (I don't know yet), if we take a 390 * completely invalid page and mark it partially valid 391 * it can screw up NFS reads, so we don't allow the case. 392 */ 393 if ((nsize & PAGE_MASK) && 394 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 395 m->valid != 0) { 396 int base = (int)nsize & PAGE_MASK; 397 int size = PAGE_SIZE - base; 398 399 /* 400 * Clear out partial-page garbage in case 401 * the page has been mapped. 402 */ 403 pmap_zero_page_area(m, base, size); 404 405 /* 406 * XXX work around SMP data integrity race 407 * by unmapping the page from user processes. 408 * The garbage we just cleared may be mapped 409 * to a user process running on another cpu 410 * and this code is not running through normal 411 * I/O channels which handle SMP issues for 412 * us, so unmap page to synchronize all cpus. 413 * 414 * XXX should vm_pager_unmap_page() have 415 * dealt with this? 416 */ 417 vm_page_lock_queues(); 418 pmap_remove_all(m); 419 420 /* 421 * Clear out partial-page dirty bits. This 422 * has the side effect of setting the valid 423 * bits, but that is ok. There are a bunch 424 * of places in the VM system where we expected 425 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 426 * case is one of them. If the page is still 427 * partially dirty, make it fully dirty. 428 * 429 * note that we do not clear out the valid 430 * bits. This would prevent bogus_page 431 * replacement from working properly. 432 */ 433 vm_page_set_validclean(m, base, size); 434 if (m->dirty != 0) 435 m->dirty = VM_PAGE_BITS_ALL; 436 vm_page_unlock_queues(); 437 } 438 } 439 object->un_pager.vnp.vnp_size = nsize; 440 object->size = nobjsize; 441 VM_OBJECT_UNLOCK(object); 442 } 443 444 /* 445 * calculate the linear (byte) disk address of specified virtual 446 * file address 447 */ 448 static daddr_t 449 vnode_pager_addr(vp, address, run) 450 struct vnode *vp; 451 vm_ooffset_t address; 452 int *run; 453 { 454 daddr_t rtaddress; 455 int bsize; 456 daddr_t block; 457 int err; 458 daddr_t vblock; 459 daddr_t voffset; 460 461 if (address < 0) 462 return -1; 463 464 if (vp->v_mount == NULL) 465 return -1; 466 467 bsize = vp->v_mount->mnt_stat.f_iosize; 468 vblock = address / bsize; 469 voffset = address % bsize; 470 471 err = VOP_BMAP(vp, vblock, NULL, &block, run, NULL); 472 473 if (err || (block == -1)) 474 rtaddress = -1; 475 else { 476 rtaddress = block + voffset / DEV_BSIZE; 477 if (run) { 478 *run += 1; 479 *run *= bsize/PAGE_SIZE; 480 *run -= voffset/PAGE_SIZE; 481 } 482 } 483 484 return rtaddress; 485 } 486 487 /* 488 * small block filesystem vnode pager input 489 */ 490 static int 491 vnode_pager_input_smlfs(object, m) 492 vm_object_t object; 493 vm_page_t m; 494 { 495 int i; 496 struct vnode *vp; 497 struct bufobj *bo; 498 struct buf *bp; 499 struct sf_buf *sf; 500 daddr_t fileaddr; 501 vm_offset_t bsize; 502 int error = 0; 503 504 vp = object->handle; 505 if (vp->v_mount == NULL) 506 return VM_PAGER_BAD; 507 508 bsize = vp->v_mount->mnt_stat.f_iosize; 509 510 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 511 512 sf = sf_buf_alloc(m, 0); 513 514 for (i = 0; i < PAGE_SIZE / bsize; i++) { 515 vm_ooffset_t address; 516 517 if (vm_page_bits(i * bsize, bsize) & m->valid) 518 continue; 519 520 address = IDX_TO_OFF(m->pindex) + i * bsize; 521 if (address >= object->un_pager.vnp.vnp_size) { 522 fileaddr = -1; 523 } else { 524 fileaddr = vnode_pager_addr(vp, address, NULL); 525 } 526 if (fileaddr != -1) { 527 bp = getpbuf(&vnode_pbuf_freecnt); 528 529 /* build a minimal buffer header */ 530 bp->b_iocmd = BIO_READ; 531 bp->b_iodone = bdone; 532 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 533 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 534 bp->b_rcred = crhold(curthread->td_ucred); 535 bp->b_wcred = crhold(curthread->td_ucred); 536 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 537 bp->b_blkno = fileaddr; 538 pbgetbo(bo, bp); 539 bp->b_bcount = bsize; 540 bp->b_bufsize = bsize; 541 bp->b_runningbufspace = bp->b_bufsize; 542 atomic_add_int(&runningbufspace, bp->b_runningbufspace); 543 544 /* do the input */ 545 bp->b_iooffset = dbtob(bp->b_blkno); 546 bstrategy(bp); 547 548 bwait(bp, PVM, "vnsrd"); 549 550 if ((bp->b_ioflags & BIO_ERROR) != 0) 551 error = EIO; 552 553 /* 554 * free the buffer header back to the swap buffer pool 555 */ 556 pbrelbo(bp); 557 relpbuf(bp, &vnode_pbuf_freecnt); 558 if (error) 559 break; 560 561 VM_OBJECT_LOCK(object); 562 vm_page_lock_queues(); 563 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 564 vm_page_unlock_queues(); 565 VM_OBJECT_UNLOCK(object); 566 } else { 567 VM_OBJECT_LOCK(object); 568 vm_page_lock_queues(); 569 vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); 570 vm_page_unlock_queues(); 571 VM_OBJECT_UNLOCK(object); 572 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 573 } 574 } 575 sf_buf_free(sf); 576 vm_page_lock_queues(); 577 pmap_clear_modify(m); 578 vm_page_unlock_queues(); 579 if (error) { 580 return VM_PAGER_ERROR; 581 } 582 return VM_PAGER_OK; 583 584 } 585 586 587 /* 588 * old style vnode pager input routine 589 */ 590 static int 591 vnode_pager_input_old(object, m) 592 vm_object_t object; 593 vm_page_t m; 594 { 595 struct uio auio; 596 struct iovec aiov; 597 int error; 598 int size; 599 struct sf_buf *sf; 600 struct vnode *vp; 601 602 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 603 error = 0; 604 605 /* 606 * Return failure if beyond current EOF 607 */ 608 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 609 return VM_PAGER_BAD; 610 } else { 611 size = PAGE_SIZE; 612 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 613 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 614 vp = object->handle; 615 VM_OBJECT_UNLOCK(object); 616 617 /* 618 * Allocate a kernel virtual address and initialize so that 619 * we can use VOP_READ/WRITE routines. 620 */ 621 sf = sf_buf_alloc(m, 0); 622 623 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 624 aiov.iov_len = size; 625 auio.uio_iov = &aiov; 626 auio.uio_iovcnt = 1; 627 auio.uio_offset = IDX_TO_OFF(m->pindex); 628 auio.uio_segflg = UIO_SYSSPACE; 629 auio.uio_rw = UIO_READ; 630 auio.uio_resid = size; 631 auio.uio_td = curthread; 632 633 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 634 if (!error) { 635 int count = size - auio.uio_resid; 636 637 if (count == 0) 638 error = EINVAL; 639 else if (count != PAGE_SIZE) 640 bzero((caddr_t)sf_buf_kva(sf) + count, 641 PAGE_SIZE - count); 642 } 643 sf_buf_free(sf); 644 645 VM_OBJECT_LOCK(object); 646 } 647 vm_page_lock_queues(); 648 pmap_clear_modify(m); 649 vm_page_undirty(m); 650 vm_page_unlock_queues(); 651 if (!error) 652 m->valid = VM_PAGE_BITS_ALL; 653 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 654 } 655 656 /* 657 * generic vnode pager input routine 658 */ 659 660 /* 661 * Local media VFS's that do not implement their own VOP_GETPAGES 662 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 663 * to implement the previous behaviour. 664 * 665 * All other FS's should use the bypass to get to the local media 666 * backing vp's VOP_GETPAGES. 667 */ 668 static int 669 vnode_pager_getpages(object, m, count, reqpage) 670 vm_object_t object; 671 vm_page_t *m; 672 int count; 673 int reqpage; 674 { 675 int rtval; 676 struct vnode *vp; 677 int bytes = count * PAGE_SIZE; 678 int vfslocked; 679 680 vp = object->handle; 681 VM_OBJECT_UNLOCK(object); 682 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 683 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 684 KASSERT(rtval != EOPNOTSUPP, 685 ("vnode_pager: FS getpages not implemented\n")); 686 VFS_UNLOCK_GIANT(vfslocked); 687 VM_OBJECT_LOCK(object); 688 return rtval; 689 } 690 691 /* 692 * This is now called from local media FS's to operate against their 693 * own vnodes if they fail to implement VOP_GETPAGES. 694 */ 695 int 696 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 697 struct vnode *vp; 698 vm_page_t *m; 699 int bytecount; 700 int reqpage; 701 { 702 vm_object_t object; 703 vm_offset_t kva; 704 off_t foff, tfoff, nextoff; 705 int i, j, size, bsize, first; 706 daddr_t firstaddr; 707 struct bufobj *bo; 708 int runpg; 709 int runend; 710 struct buf *bp; 711 int count; 712 int error = 0; 713 714 object = vp->v_object; 715 count = bytecount / PAGE_SIZE; 716 717 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 718 ("vnode_pager_generic_getpages does not support devices")); 719 if (vp->v_mount == NULL) 720 return VM_PAGER_BAD; 721 722 bsize = vp->v_mount->mnt_stat.f_iosize; 723 724 /* get the UNDERLYING device for the file with VOP_BMAP() */ 725 726 /* 727 * originally, we did not check for an error return value -- assuming 728 * an fs always has a bmap entry point -- that assumption is wrong!!! 729 */ 730 foff = IDX_TO_OFF(m[reqpage]->pindex); 731 732 /* 733 * if we can't bmap, use old VOP code 734 */ 735 if (VOP_BMAP(vp, 0, &bo, 0, NULL, NULL)) { 736 VM_OBJECT_LOCK(object); 737 vm_page_lock_queues(); 738 for (i = 0; i < count; i++) 739 if (i != reqpage) 740 vm_page_free(m[i]); 741 vm_page_unlock_queues(); 742 cnt.v_vnodein++; 743 cnt.v_vnodepgsin++; 744 error = vnode_pager_input_old(object, m[reqpage]); 745 VM_OBJECT_UNLOCK(object); 746 return (error); 747 748 /* 749 * if the blocksize is smaller than a page size, then use 750 * special small filesystem code. NFS sometimes has a small 751 * blocksize, but it can handle large reads itself. 752 */ 753 } else if ((PAGE_SIZE / bsize) > 1 && 754 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 755 VM_OBJECT_LOCK(object); 756 vm_page_lock_queues(); 757 for (i = 0; i < count; i++) 758 if (i != reqpage) 759 vm_page_free(m[i]); 760 vm_page_unlock_queues(); 761 VM_OBJECT_UNLOCK(object); 762 cnt.v_vnodein++; 763 cnt.v_vnodepgsin++; 764 return vnode_pager_input_smlfs(object, m[reqpage]); 765 } 766 767 /* 768 * If we have a completely valid page available to us, we can 769 * clean up and return. Otherwise we have to re-read the 770 * media. 771 */ 772 VM_OBJECT_LOCK(object); 773 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 774 vm_page_lock_queues(); 775 for (i = 0; i < count; i++) 776 if (i != reqpage) 777 vm_page_free(m[i]); 778 vm_page_unlock_queues(); 779 VM_OBJECT_UNLOCK(object); 780 return VM_PAGER_OK; 781 } 782 m[reqpage]->valid = 0; 783 VM_OBJECT_UNLOCK(object); 784 785 /* 786 * here on direct device I/O 787 */ 788 firstaddr = -1; 789 790 /* 791 * calculate the run that includes the required page 792 */ 793 for (first = 0, i = 0; i < count; i = runend) { 794 firstaddr = vnode_pager_addr(vp, 795 IDX_TO_OFF(m[i]->pindex), &runpg); 796 if (firstaddr == -1) { 797 VM_OBJECT_LOCK(object); 798 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 799 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 800 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 801 (uintmax_t)foff, 802 (uintmax_t) 803 (object->un_pager.vnp.vnp_size >> 32), 804 (uintmax_t)object->un_pager.vnp.vnp_size); 805 } 806 vm_page_lock_queues(); 807 vm_page_free(m[i]); 808 vm_page_unlock_queues(); 809 VM_OBJECT_UNLOCK(object); 810 runend = i + 1; 811 first = runend; 812 continue; 813 } 814 runend = i + runpg; 815 if (runend <= reqpage) { 816 VM_OBJECT_LOCK(object); 817 vm_page_lock_queues(); 818 for (j = i; j < runend; j++) 819 vm_page_free(m[j]); 820 vm_page_unlock_queues(); 821 VM_OBJECT_UNLOCK(object); 822 } else { 823 if (runpg < (count - first)) { 824 VM_OBJECT_LOCK(object); 825 vm_page_lock_queues(); 826 for (i = first + runpg; i < count; i++) 827 vm_page_free(m[i]); 828 vm_page_unlock_queues(); 829 VM_OBJECT_UNLOCK(object); 830 count = first + runpg; 831 } 832 break; 833 } 834 first = runend; 835 } 836 837 /* 838 * the first and last page have been calculated now, move input pages 839 * to be zero based... 840 */ 841 if (first != 0) { 842 for (i = first; i < count; i++) { 843 m[i - first] = m[i]; 844 } 845 count -= first; 846 reqpage -= first; 847 } 848 849 /* 850 * calculate the file virtual address for the transfer 851 */ 852 foff = IDX_TO_OFF(m[0]->pindex); 853 854 /* 855 * calculate the size of the transfer 856 */ 857 size = count * PAGE_SIZE; 858 KASSERT(count > 0, ("zero count")); 859 if ((foff + size) > object->un_pager.vnp.vnp_size) 860 size = object->un_pager.vnp.vnp_size - foff; 861 KASSERT(size > 0, ("zero size")); 862 863 /* 864 * round up physical size for real devices. 865 */ 866 if (1) { 867 int secmask = bo->bo_bsize - 1; 868 KASSERT(secmask < PAGE_SIZE && secmask > 0, 869 ("vnode_pager_generic_getpages: sector size %d too large", 870 secmask + 1)); 871 size = (size + secmask) & ~secmask; 872 } 873 874 bp = getpbuf(&vnode_pbuf_freecnt); 875 kva = (vm_offset_t) bp->b_data; 876 877 /* 878 * and map the pages to be read into the kva 879 */ 880 pmap_qenter(kva, m, count); 881 882 /* build a minimal buffer header */ 883 bp->b_iocmd = BIO_READ; 884 bp->b_iodone = bdone; 885 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 886 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 887 bp->b_rcred = crhold(curthread->td_ucred); 888 bp->b_wcred = crhold(curthread->td_ucred); 889 bp->b_blkno = firstaddr; 890 pbgetbo(bo, bp); 891 bp->b_bcount = size; 892 bp->b_bufsize = size; 893 bp->b_runningbufspace = bp->b_bufsize; 894 atomic_add_int(&runningbufspace, bp->b_runningbufspace); 895 896 cnt.v_vnodein++; 897 cnt.v_vnodepgsin += count; 898 899 /* do the input */ 900 bp->b_iooffset = dbtob(bp->b_blkno); 901 bstrategy(bp); 902 903 bwait(bp, PVM, "vnread"); 904 905 if ((bp->b_ioflags & BIO_ERROR) != 0) 906 error = EIO; 907 908 if (!error) { 909 if (size != count * PAGE_SIZE) 910 bzero((caddr_t) kva + size, PAGE_SIZE * count - size); 911 } 912 pmap_qremove(kva, count); 913 914 /* 915 * free the buffer header back to the swap buffer pool 916 */ 917 pbrelbo(bp); 918 relpbuf(bp, &vnode_pbuf_freecnt); 919 920 VM_OBJECT_LOCK(object); 921 vm_page_lock_queues(); 922 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 923 vm_page_t mt; 924 925 nextoff = tfoff + PAGE_SIZE; 926 mt = m[i]; 927 928 if (nextoff <= object->un_pager.vnp.vnp_size) { 929 /* 930 * Read filled up entire page. 931 */ 932 mt->valid = VM_PAGE_BITS_ALL; 933 vm_page_undirty(mt); /* should be an assert? XXX */ 934 pmap_clear_modify(mt); 935 } else { 936 /* 937 * Read did not fill up entire page. Since this 938 * is getpages, the page may be mapped, so we have 939 * to zero the invalid portions of the page even 940 * though we aren't setting them valid. 941 * 942 * Currently we do not set the entire page valid, 943 * we just try to clear the piece that we couldn't 944 * read. 945 */ 946 vm_page_set_validclean(mt, 0, 947 object->un_pager.vnp.vnp_size - tfoff); 948 /* handled by vm_fault now */ 949 /* vm_page_zero_invalid(mt, FALSE); */ 950 } 951 952 if (i != reqpage) { 953 954 /* 955 * whether or not to leave the page activated is up in 956 * the air, but we should put the page on a page queue 957 * somewhere. (it already is in the object). Result: 958 * It appears that empirical results show that 959 * deactivating pages is best. 960 */ 961 962 /* 963 * just in case someone was asking for this page we 964 * now tell them that it is ok to use 965 */ 966 if (!error) { 967 if (mt->flags & PG_WANTED) 968 vm_page_activate(mt); 969 else 970 vm_page_deactivate(mt); 971 vm_page_wakeup(mt); 972 } else { 973 vm_page_free(mt); 974 } 975 } 976 } 977 vm_page_unlock_queues(); 978 VM_OBJECT_UNLOCK(object); 979 if (error) { 980 printf("vnode_pager_getpages: I/O read error\n"); 981 } 982 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 983 } 984 985 /* 986 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 987 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 988 * vnode_pager_generic_putpages() to implement the previous behaviour. 989 * 990 * All other FS's should use the bypass to get to the local media 991 * backing vp's VOP_PUTPAGES. 992 */ 993 static void 994 vnode_pager_putpages(object, m, count, sync, rtvals) 995 vm_object_t object; 996 vm_page_t *m; 997 int count; 998 boolean_t sync; 999 int *rtvals; 1000 { 1001 int rtval; 1002 struct vnode *vp; 1003 struct mount *mp; 1004 int bytes = count * PAGE_SIZE; 1005 1006 /* 1007 * Force synchronous operation if we are extremely low on memory 1008 * to prevent a low-memory deadlock. VOP operations often need to 1009 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1010 * operation ). The swapper handles the case by limiting the amount 1011 * of asynchronous I/O, but that sort of solution doesn't scale well 1012 * for the vnode pager without a lot of work. 1013 * 1014 * Also, the backing vnode's iodone routine may not wake the pageout 1015 * daemon up. This should be probably be addressed XXX. 1016 */ 1017 1018 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 1019 sync |= OBJPC_SYNC; 1020 1021 /* 1022 * Call device-specific putpages function 1023 */ 1024 vp = object->handle; 1025 VM_OBJECT_UNLOCK(object); 1026 if (vp->v_type != VREG) 1027 mp = NULL; 1028 (void)vn_start_write(vp, &mp, V_WAIT); 1029 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 1030 KASSERT(rtval != EOPNOTSUPP, 1031 ("vnode_pager: stale FS putpages\n")); 1032 vn_finished_write(mp); 1033 VM_OBJECT_LOCK(object); 1034 } 1035 1036 1037 /* 1038 * This is now called from local media FS's to operate against their 1039 * own vnodes if they fail to implement VOP_PUTPAGES. 1040 * 1041 * This is typically called indirectly via the pageout daemon and 1042 * clustering has already typically occured, so in general we ask the 1043 * underlying filesystem to write the data out asynchronously rather 1044 * then delayed. 1045 */ 1046 int 1047 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) 1048 struct vnode *vp; 1049 vm_page_t *m; 1050 int bytecount; 1051 int flags; 1052 int *rtvals; 1053 { 1054 int i; 1055 vm_object_t object; 1056 int count; 1057 1058 int maxsize, ncount; 1059 vm_ooffset_t poffset; 1060 struct uio auio; 1061 struct iovec aiov; 1062 int error; 1063 int ioflags; 1064 1065 object = vp->v_object; 1066 count = bytecount / PAGE_SIZE; 1067 1068 for (i = 0; i < count; i++) 1069 rtvals[i] = VM_PAGER_AGAIN; 1070 1071 if ((int64_t)m[0]->pindex < 0) { 1072 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1073 (long)m[0]->pindex, (u_long)m[0]->dirty); 1074 rtvals[0] = VM_PAGER_BAD; 1075 return VM_PAGER_BAD; 1076 } 1077 1078 maxsize = count * PAGE_SIZE; 1079 ncount = count; 1080 1081 poffset = IDX_TO_OFF(m[0]->pindex); 1082 1083 /* 1084 * If the page-aligned write is larger then the actual file we 1085 * have to invalidate pages occuring beyond the file EOF. However, 1086 * there is an edge case where a file may not be page-aligned where 1087 * the last page is partially invalid. In this case the filesystem 1088 * may not properly clear the dirty bits for the entire page (which 1089 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1090 * With the page locked we are free to fix-up the dirty bits here. 1091 * 1092 * We do not under any circumstances truncate the valid bits, as 1093 * this will screw up bogus page replacement. 1094 */ 1095 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1096 if (object->un_pager.vnp.vnp_size > poffset) { 1097 int pgoff; 1098 1099 maxsize = object->un_pager.vnp.vnp_size - poffset; 1100 ncount = btoc(maxsize); 1101 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1102 vm_page_lock_queues(); 1103 vm_page_clear_dirty(m[ncount - 1], pgoff, 1104 PAGE_SIZE - pgoff); 1105 vm_page_unlock_queues(); 1106 } 1107 } else { 1108 maxsize = 0; 1109 ncount = 0; 1110 } 1111 if (ncount < count) { 1112 for (i = ncount; i < count; i++) { 1113 rtvals[i] = VM_PAGER_BAD; 1114 } 1115 } 1116 } 1117 1118 /* 1119 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1120 * rather then a bdwrite() to prevent paging I/O from saturating 1121 * the buffer cache. Dummy-up the sequential heuristic to cause 1122 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1123 * the system decides how to cluster. 1124 */ 1125 ioflags = IO_VMIO; 1126 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1127 ioflags |= IO_SYNC; 1128 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1129 ioflags |= IO_ASYNC; 1130 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1131 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1132 1133 aiov.iov_base = (caddr_t) 0; 1134 aiov.iov_len = maxsize; 1135 auio.uio_iov = &aiov; 1136 auio.uio_iovcnt = 1; 1137 auio.uio_offset = poffset; 1138 auio.uio_segflg = UIO_NOCOPY; 1139 auio.uio_rw = UIO_WRITE; 1140 auio.uio_resid = maxsize; 1141 auio.uio_td = (struct thread *) 0; 1142 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1143 cnt.v_vnodeout++; 1144 cnt.v_vnodepgsout += ncount; 1145 1146 if (error) { 1147 printf("vnode_pager_putpages: I/O error %d\n", error); 1148 } 1149 if (auio.uio_resid) { 1150 printf("vnode_pager_putpages: residual I/O %d at %lu\n", 1151 auio.uio_resid, (u_long)m[0]->pindex); 1152 } 1153 for (i = 0; i < ncount; i++) { 1154 rtvals[i] = VM_PAGER_OK; 1155 } 1156 return rtvals[0]; 1157 } 1158 1159 struct vnode * 1160 vnode_pager_lock(vm_object_t first_object) 1161 { 1162 struct vnode *vp; 1163 vm_object_t backing_object, object; 1164 1165 VM_OBJECT_LOCK_ASSERT(first_object, MA_OWNED); 1166 for (object = first_object; object != NULL; object = backing_object) { 1167 if (object->type != OBJT_VNODE) { 1168 if ((backing_object = object->backing_object) != NULL) 1169 VM_OBJECT_LOCK(backing_object); 1170 if (object != first_object) 1171 VM_OBJECT_UNLOCK(object); 1172 continue; 1173 } 1174 retry: 1175 if (object->flags & OBJ_DEAD) { 1176 if (object != first_object) 1177 VM_OBJECT_UNLOCK(object); 1178 return NULL; 1179 } 1180 vp = object->handle; 1181 VI_LOCK(vp); 1182 VM_OBJECT_UNLOCK(object); 1183 if (first_object != object) 1184 VM_OBJECT_UNLOCK(first_object); 1185 VFS_ASSERT_GIANT(vp->v_mount); 1186 if (vget(vp, LK_CANRECURSE | LK_INTERLOCK | 1187 LK_RETRY | LK_SHARED, curthread)) { 1188 VM_OBJECT_LOCK(first_object); 1189 if (object != first_object) 1190 VM_OBJECT_LOCK(object); 1191 if (object->type != OBJT_VNODE) { 1192 if (object != first_object) 1193 VM_OBJECT_UNLOCK(object); 1194 return NULL; 1195 } 1196 printf("vnode_pager_lock: retrying\n"); 1197 goto retry; 1198 } 1199 VM_OBJECT_LOCK(first_object); 1200 return (vp); 1201 } 1202 return NULL; 1203 }
Cache object: d0286d9caa1f3dad3239a0ebac7abb75
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]