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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("$FreeBSD$"); 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_param.h> 72 #include <vm/vm_object.h> 73 #include <vm/vm_page.h> 74 #include <vm/vm_pager.h> 75 #include <vm/vm_map.h> 76 #include <vm/vnode_pager.h> 77 #include <vm/vm_extern.h> 78 79 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 80 daddr_t *rtaddress, int *run); 81 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 82 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 83 static void vnode_pager_dealloc(vm_object_t); 84 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 85 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); 86 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 87 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 88 vm_ooffset_t, struct ucred *cred); 89 90 struct pagerops vnodepagerops = { 91 .pgo_alloc = vnode_pager_alloc, 92 .pgo_dealloc = vnode_pager_dealloc, 93 .pgo_getpages = vnode_pager_getpages, 94 .pgo_putpages = vnode_pager_putpages, 95 .pgo_haspage = vnode_pager_haspage, 96 }; 97 98 int vnode_pbuf_freecnt; 99 100 /* Create the VM system backing object for this vnode */ 101 int 102 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 103 { 104 vm_object_t object; 105 vm_ooffset_t size = isize; 106 struct vattr va; 107 108 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 109 return (0); 110 111 while ((object = vp->v_object) != NULL) { 112 VM_OBJECT_LOCK(object); 113 if (!(object->flags & OBJ_DEAD)) { 114 VM_OBJECT_UNLOCK(object); 115 return (0); 116 } 117 VOP_UNLOCK(vp, 0); 118 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 119 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0); 120 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 121 } 122 123 if (size == 0) { 124 if (vn_isdisk(vp, NULL)) { 125 size = IDX_TO_OFF(INT_MAX); 126 } else { 127 if (VOP_GETATTR(vp, &va, td->td_ucred)) 128 return (0); 129 size = va.va_size; 130 } 131 } 132 133 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 134 /* 135 * Dereference the reference we just created. This assumes 136 * that the object is associated with the vp. 137 */ 138 VM_OBJECT_LOCK(object); 139 object->ref_count--; 140 VM_OBJECT_UNLOCK(object); 141 vrele(vp); 142 143 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 144 145 return (0); 146 } 147 148 void 149 vnode_destroy_vobject(struct vnode *vp) 150 { 151 struct vm_object *obj; 152 153 obj = vp->v_object; 154 if (obj == NULL) 155 return; 156 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 157 VM_OBJECT_LOCK(obj); 158 if (obj->ref_count == 0) { 159 /* 160 * vclean() may be called twice. The first time 161 * removes the primary reference to the object, 162 * the second time goes one further and is a 163 * special-case to terminate the object. 164 * 165 * don't double-terminate the object 166 */ 167 if ((obj->flags & OBJ_DEAD) == 0) 168 vm_object_terminate(obj); 169 else 170 VM_OBJECT_UNLOCK(obj); 171 } else { 172 /* 173 * Woe to the process that tries to page now :-). 174 */ 175 vm_pager_deallocate(obj); 176 VM_OBJECT_UNLOCK(obj); 177 } 178 vp->v_object = NULL; 179 } 180 181 182 /* 183 * Allocate (or lookup) pager for a vnode. 184 * Handle is a vnode pointer. 185 * 186 * MPSAFE 187 */ 188 vm_object_t 189 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 190 vm_ooffset_t offset, struct ucred *cred) 191 { 192 vm_object_t object; 193 struct vnode *vp; 194 195 /* 196 * Pageout to vnode, no can do yet. 197 */ 198 if (handle == NULL) 199 return (NULL); 200 201 vp = (struct vnode *) handle; 202 203 /* 204 * If the object is being terminated, wait for it to 205 * go away. 206 */ 207 retry: 208 while ((object = vp->v_object) != NULL) { 209 VM_OBJECT_LOCK(object); 210 if ((object->flags & OBJ_DEAD) == 0) 211 break; 212 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 213 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); 214 } 215 216 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference")); 217 218 if (object == NULL) { 219 /* 220 * Add an object of the appropriate size 221 */ 222 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 223 224 object->un_pager.vnp.vnp_size = size; 225 object->un_pager.vnp.writemappings = 0; 226 227 object->handle = handle; 228 VI_LOCK(vp); 229 if (vp->v_object != NULL) { 230 /* 231 * Object has been created while we were sleeping 232 */ 233 VI_UNLOCK(vp); 234 VM_OBJECT_LOCK(object); 235 KASSERT(object->ref_count == 1, 236 ("leaked ref %p %d", object, object->ref_count)); 237 object->type = OBJT_DEAD; 238 object->ref_count = 0; 239 VM_OBJECT_UNLOCK(object); 240 vm_object_destroy(object); 241 goto retry; 242 } 243 vp->v_object = object; 244 VI_UNLOCK(vp); 245 } else { 246 object->ref_count++; 247 VM_OBJECT_UNLOCK(object); 248 } 249 vref(vp); 250 return (object); 251 } 252 253 /* 254 * The object must be locked. 255 */ 256 static void 257 vnode_pager_dealloc(object) 258 vm_object_t object; 259 { 260 struct vnode *vp; 261 int refs; 262 263 vp = object->handle; 264 if (vp == NULL) 265 panic("vnode_pager_dealloc: pager already dealloced"); 266 267 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 268 vm_object_pip_wait(object, "vnpdea"); 269 refs = object->ref_count; 270 271 object->handle = NULL; 272 object->type = OBJT_DEAD; 273 if (object->flags & OBJ_DISCONNECTWNT) { 274 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 275 wakeup(object); 276 } 277 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 278 if (object->un_pager.vnp.writemappings > 0) { 279 object->un_pager.vnp.writemappings = 0; 280 VOP_ADD_WRITECOUNT(vp, -1); 281 } 282 vp->v_object = NULL; 283 VOP_UNSET_TEXT(vp); 284 VM_OBJECT_UNLOCK(object); 285 while (refs-- > 0) 286 vunref(vp); 287 VM_OBJECT_LOCK(object); 288 } 289 290 static boolean_t 291 vnode_pager_haspage(object, pindex, before, after) 292 vm_object_t object; 293 vm_pindex_t pindex; 294 int *before; 295 int *after; 296 { 297 struct vnode *vp = object->handle; 298 daddr_t bn; 299 int err; 300 daddr_t reqblock; 301 int poff; 302 int bsize; 303 int pagesperblock, blocksperpage; 304 int vfslocked; 305 306 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 307 /* 308 * If no vp or vp is doomed or marked transparent to VM, we do not 309 * have the page. 310 */ 311 if (vp == NULL || vp->v_iflag & VI_DOOMED) 312 return FALSE; 313 /* 314 * If the offset is beyond end of file we do 315 * not have the page. 316 */ 317 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 318 return FALSE; 319 320 bsize = vp->v_mount->mnt_stat.f_iosize; 321 pagesperblock = bsize / PAGE_SIZE; 322 blocksperpage = 0; 323 if (pagesperblock > 0) { 324 reqblock = pindex / pagesperblock; 325 } else { 326 blocksperpage = (PAGE_SIZE / bsize); 327 reqblock = pindex * blocksperpage; 328 } 329 VM_OBJECT_UNLOCK(object); 330 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 331 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 332 VFS_UNLOCK_GIANT(vfslocked); 333 VM_OBJECT_LOCK(object); 334 if (err) 335 return TRUE; 336 if (bn == -1) 337 return FALSE; 338 if (pagesperblock > 0) { 339 poff = pindex - (reqblock * pagesperblock); 340 if (before) { 341 *before *= pagesperblock; 342 *before += poff; 343 } 344 if (after) { 345 int numafter; 346 *after *= pagesperblock; 347 numafter = pagesperblock - (poff + 1); 348 if (IDX_TO_OFF(pindex + numafter) > 349 object->un_pager.vnp.vnp_size) { 350 numafter = 351 OFF_TO_IDX(object->un_pager.vnp.vnp_size) - 352 pindex; 353 } 354 *after += numafter; 355 } 356 } else { 357 if (before) { 358 *before /= blocksperpage; 359 } 360 361 if (after) { 362 *after /= blocksperpage; 363 } 364 } 365 return TRUE; 366 } 367 368 /* 369 * Lets the VM system know about a change in size for a file. 370 * We adjust our own internal size and flush any cached pages in 371 * the associated object that are affected by the size change. 372 * 373 * Note: this routine may be invoked as a result of a pager put 374 * operation (possibly at object termination time), so we must be careful. 375 */ 376 void 377 vnode_pager_setsize(vp, nsize) 378 struct vnode *vp; 379 vm_ooffset_t nsize; 380 { 381 vm_object_t object; 382 vm_page_t m; 383 vm_pindex_t nobjsize; 384 385 if ((object = vp->v_object) == NULL) 386 return; 387 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 388 VM_OBJECT_LOCK(object); 389 if (object->type == OBJT_DEAD) { 390 VM_OBJECT_UNLOCK(object); 391 return; 392 } 393 KASSERT(object->type == OBJT_VNODE, 394 ("not vnode-backed object %p", object)); 395 if (nsize == object->un_pager.vnp.vnp_size) { 396 /* 397 * Hasn't changed size 398 */ 399 VM_OBJECT_UNLOCK(object); 400 return; 401 } 402 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 403 if (nsize < object->un_pager.vnp.vnp_size) { 404 /* 405 * File has shrunk. Toss any cached pages beyond the new EOF. 406 */ 407 if (nobjsize < object->size) 408 vm_object_page_remove(object, nobjsize, object->size, 409 0); 410 /* 411 * this gets rid of garbage at the end of a page that is now 412 * only partially backed by the vnode. 413 * 414 * XXX for some reason (I don't know yet), if we take a 415 * completely invalid page and mark it partially valid 416 * it can screw up NFS reads, so we don't allow the case. 417 */ 418 if ((nsize & PAGE_MASK) && 419 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 420 m->valid != 0) { 421 int base = (int)nsize & PAGE_MASK; 422 int size = PAGE_SIZE - base; 423 424 /* 425 * Clear out partial-page garbage in case 426 * the page has been mapped. 427 */ 428 pmap_zero_page_area(m, base, size); 429 430 /* 431 * Update the valid bits to reflect the blocks that 432 * have been zeroed. Some of these valid bits may 433 * have already been set. 434 */ 435 vm_page_set_valid(m, base, size); 436 437 /* 438 * Round "base" to the next block boundary so that the 439 * dirty bit for a partially zeroed block is not 440 * cleared. 441 */ 442 base = roundup2(base, DEV_BSIZE); 443 444 /* 445 * Clear out partial-page dirty bits. 446 * 447 * note that we do not clear out the valid 448 * bits. This would prevent bogus_page 449 * replacement from working properly. 450 */ 451 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 452 } else if ((nsize & PAGE_MASK) && 453 __predict_false(object->cache != NULL)) { 454 vm_page_cache_free(object, OFF_TO_IDX(nsize), 455 nobjsize); 456 } 457 } 458 object->un_pager.vnp.vnp_size = nsize; 459 object->size = nobjsize; 460 VM_OBJECT_UNLOCK(object); 461 } 462 463 /* 464 * calculate the linear (byte) disk address of specified virtual 465 * file address 466 */ 467 static int 468 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 469 int *run) 470 { 471 int bsize; 472 int err; 473 daddr_t vblock; 474 daddr_t voffset; 475 476 if (address < 0) 477 return -1; 478 479 if (vp->v_iflag & VI_DOOMED) 480 return -1; 481 482 bsize = vp->v_mount->mnt_stat.f_iosize; 483 vblock = address / bsize; 484 voffset = address % bsize; 485 486 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 487 if (err == 0) { 488 if (*rtaddress != -1) 489 *rtaddress += voffset / DEV_BSIZE; 490 if (run) { 491 *run += 1; 492 *run *= bsize/PAGE_SIZE; 493 *run -= voffset/PAGE_SIZE; 494 } 495 } 496 497 return (err); 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 struct vnode *vp; 509 struct bufobj *bo; 510 struct buf *bp; 511 struct sf_buf *sf; 512 daddr_t fileaddr; 513 vm_offset_t bsize; 514 vm_page_bits_t bits; 515 int error, i; 516 517 error = 0; 518 vp = object->handle; 519 if (vp->v_iflag & VI_DOOMED) 520 return VM_PAGER_BAD; 521 522 bsize = vp->v_mount->mnt_stat.f_iosize; 523 524 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 525 526 sf = sf_buf_alloc(m, 0); 527 528 for (i = 0; i < PAGE_SIZE / bsize; i++) { 529 vm_ooffset_t address; 530 531 bits = vm_page_bits(i * bsize, bsize); 532 if (m->valid & bits) 533 continue; 534 535 address = IDX_TO_OFF(m->pindex) + i * bsize; 536 if (address >= object->un_pager.vnp.vnp_size) { 537 fileaddr = -1; 538 } else { 539 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 540 if (error) 541 break; 542 } 543 if (fileaddr != -1) { 544 bp = getpbuf(&vnode_pbuf_freecnt); 545 546 /* build a minimal buffer header */ 547 bp->b_iocmd = BIO_READ; 548 bp->b_iodone = bdone; 549 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 550 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 551 bp->b_rcred = crhold(curthread->td_ucred); 552 bp->b_wcred = crhold(curthread->td_ucred); 553 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 554 bp->b_blkno = fileaddr; 555 pbgetbo(bo, bp); 556 bp->b_vp = vp; 557 bp->b_bcount = bsize; 558 bp->b_bufsize = bsize; 559 bp->b_runningbufspace = bp->b_bufsize; 560 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 561 562 /* do the input */ 563 bp->b_iooffset = dbtob(bp->b_blkno); 564 bstrategy(bp); 565 566 bwait(bp, PVM, "vnsrd"); 567 568 if ((bp->b_ioflags & BIO_ERROR) != 0) 569 error = EIO; 570 571 /* 572 * free the buffer header back to the swap buffer pool 573 */ 574 bp->b_vp = NULL; 575 pbrelbo(bp); 576 relpbuf(bp, &vnode_pbuf_freecnt); 577 if (error) 578 break; 579 } else 580 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 581 KASSERT((m->dirty & bits) == 0, 582 ("vnode_pager_input_smlfs: page %p is dirty", m)); 583 VM_OBJECT_LOCK(object); 584 m->valid |= bits; 585 VM_OBJECT_UNLOCK(object); 586 } 587 sf_buf_free(sf); 588 if (error) { 589 return VM_PAGER_ERROR; 590 } 591 return VM_PAGER_OK; 592 } 593 594 /* 595 * old style vnode pager input routine 596 */ 597 static int 598 vnode_pager_input_old(object, m) 599 vm_object_t object; 600 vm_page_t m; 601 { 602 struct uio auio; 603 struct iovec aiov; 604 int error; 605 int size; 606 struct sf_buf *sf; 607 struct vnode *vp; 608 609 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 610 error = 0; 611 612 /* 613 * Return failure if beyond current EOF 614 */ 615 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 616 return VM_PAGER_BAD; 617 } else { 618 size = PAGE_SIZE; 619 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 620 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 621 vp = object->handle; 622 VM_OBJECT_UNLOCK(object); 623 624 /* 625 * Allocate a kernel virtual address and initialize so that 626 * we can use VOP_READ/WRITE routines. 627 */ 628 sf = sf_buf_alloc(m, 0); 629 630 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 631 aiov.iov_len = size; 632 auio.uio_iov = &aiov; 633 auio.uio_iovcnt = 1; 634 auio.uio_offset = IDX_TO_OFF(m->pindex); 635 auio.uio_segflg = UIO_SYSSPACE; 636 auio.uio_rw = UIO_READ; 637 auio.uio_resid = size; 638 auio.uio_td = curthread; 639 640 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 641 if (!error) { 642 int count = size - auio.uio_resid; 643 644 if (count == 0) 645 error = EINVAL; 646 else if (count != PAGE_SIZE) 647 bzero((caddr_t)sf_buf_kva(sf) + count, 648 PAGE_SIZE - count); 649 } 650 sf_buf_free(sf); 651 652 VM_OBJECT_LOCK(object); 653 } 654 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 655 if (!error) 656 m->valid = VM_PAGE_BITS_ALL; 657 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 658 } 659 660 /* 661 * generic vnode pager input routine 662 */ 663 664 /* 665 * Local media VFS's that do not implement their own VOP_GETPAGES 666 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 667 * to implement the previous behaviour. 668 * 669 * All other FS's should use the bypass to get to the local media 670 * backing vp's VOP_GETPAGES. 671 */ 672 static int 673 vnode_pager_getpages(object, m, count, reqpage) 674 vm_object_t object; 675 vm_page_t *m; 676 int count; 677 int reqpage; 678 { 679 int rtval; 680 struct vnode *vp; 681 int bytes = count * PAGE_SIZE; 682 int vfslocked; 683 684 vp = object->handle; 685 VM_OBJECT_UNLOCK(object); 686 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 687 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 688 KASSERT(rtval != EOPNOTSUPP, 689 ("vnode_pager: FS getpages not implemented\n")); 690 VFS_UNLOCK_GIANT(vfslocked); 691 VM_OBJECT_LOCK(object); 692 return rtval; 693 } 694 695 /* 696 * This is now called from local media FS's to operate against their 697 * own vnodes if they fail to implement VOP_GETPAGES. 698 */ 699 int 700 vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 701 struct vnode *vp; 702 vm_page_t *m; 703 int bytecount; 704 int reqpage; 705 { 706 vm_object_t object; 707 vm_offset_t kva; 708 off_t foff, tfoff, nextoff; 709 int i, j, size, bsize, first; 710 daddr_t firstaddr, reqblock; 711 struct bufobj *bo; 712 int runpg; 713 int runend; 714 struct buf *bp; 715 struct mount *mp; 716 int count; 717 int error; 718 719 object = vp->v_object; 720 count = bytecount / PAGE_SIZE; 721 722 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 723 ("vnode_pager_generic_getpages does not support devices")); 724 if (vp->v_iflag & VI_DOOMED) 725 return VM_PAGER_BAD; 726 727 bsize = vp->v_mount->mnt_stat.f_iosize; 728 729 /* get the UNDERLYING device for the file with VOP_BMAP() */ 730 731 /* 732 * originally, we did not check for an error return value -- assuming 733 * an fs always has a bmap entry point -- that assumption is wrong!!! 734 */ 735 foff = IDX_TO_OFF(m[reqpage]->pindex); 736 737 /* 738 * if we can't bmap, use old VOP code 739 */ 740 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL); 741 if (error == EOPNOTSUPP) { 742 VM_OBJECT_LOCK(object); 743 744 for (i = 0; i < count; i++) 745 if (i != reqpage) { 746 vm_page_lock(m[i]); 747 vm_page_free(m[i]); 748 vm_page_unlock(m[i]); 749 } 750 PCPU_INC(cnt.v_vnodein); 751 PCPU_INC(cnt.v_vnodepgsin); 752 error = vnode_pager_input_old(object, m[reqpage]); 753 VM_OBJECT_UNLOCK(object); 754 return (error); 755 } else if (error != 0) { 756 VM_OBJECT_LOCK(object); 757 for (i = 0; i < count; i++) 758 if (i != reqpage) { 759 vm_page_lock(m[i]); 760 vm_page_free(m[i]); 761 vm_page_unlock(m[i]); 762 } 763 VM_OBJECT_UNLOCK(object); 764 return (VM_PAGER_ERROR); 765 766 /* 767 * if the blocksize is smaller than a page size, then use 768 * special small filesystem code. NFS sometimes has a small 769 * blocksize, but it can handle large reads itself. 770 */ 771 } else if ((PAGE_SIZE / bsize) > 1 && 772 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 773 VM_OBJECT_LOCK(object); 774 for (i = 0; i < count; i++) 775 if (i != reqpage) { 776 vm_page_lock(m[i]); 777 vm_page_free(m[i]); 778 vm_page_unlock(m[i]); 779 } 780 VM_OBJECT_UNLOCK(object); 781 PCPU_INC(cnt.v_vnodein); 782 PCPU_INC(cnt.v_vnodepgsin); 783 return vnode_pager_input_smlfs(object, m[reqpage]); 784 } 785 786 /* 787 * If we have a completely valid page available to us, we can 788 * clean up and return. Otherwise we have to re-read the 789 * media. 790 */ 791 VM_OBJECT_LOCK(object); 792 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 793 for (i = 0; i < count; i++) 794 if (i != reqpage) { 795 vm_page_lock(m[i]); 796 vm_page_free(m[i]); 797 vm_page_unlock(m[i]); 798 } 799 VM_OBJECT_UNLOCK(object); 800 return VM_PAGER_OK; 801 } else if (reqblock == -1) { 802 pmap_zero_page(m[reqpage]); 803 KASSERT(m[reqpage]->dirty == 0, 804 ("vnode_pager_generic_getpages: page %p is dirty", m)); 805 m[reqpage]->valid = VM_PAGE_BITS_ALL; 806 for (i = 0; i < count; i++) 807 if (i != reqpage) { 808 vm_page_lock(m[i]); 809 vm_page_free(m[i]); 810 vm_page_unlock(m[i]); 811 } 812 VM_OBJECT_UNLOCK(object); 813 return (VM_PAGER_OK); 814 } 815 m[reqpage]->valid = 0; 816 VM_OBJECT_UNLOCK(object); 817 818 /* 819 * here on direct device I/O 820 */ 821 firstaddr = -1; 822 823 /* 824 * calculate the run that includes the required page 825 */ 826 for (first = 0, i = 0; i < count; i = runend) { 827 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr, 828 &runpg) != 0) { 829 VM_OBJECT_LOCK(object); 830 for (; i < count; i++) 831 if (i != reqpage) { 832 vm_page_lock(m[i]); 833 vm_page_free(m[i]); 834 vm_page_unlock(m[i]); 835 } 836 VM_OBJECT_UNLOCK(object); 837 return (VM_PAGER_ERROR); 838 } 839 if (firstaddr == -1) { 840 VM_OBJECT_LOCK(object); 841 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 842 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 843 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 844 (uintmax_t)foff, 845 (uintmax_t) 846 (object->un_pager.vnp.vnp_size >> 32), 847 (uintmax_t)object->un_pager.vnp.vnp_size); 848 } 849 vm_page_lock(m[i]); 850 vm_page_free(m[i]); 851 vm_page_unlock(m[i]); 852 VM_OBJECT_UNLOCK(object); 853 runend = i + 1; 854 first = runend; 855 continue; 856 } 857 runend = i + runpg; 858 if (runend <= reqpage) { 859 VM_OBJECT_LOCK(object); 860 for (j = i; j < runend; j++) { 861 vm_page_lock(m[j]); 862 vm_page_free(m[j]); 863 vm_page_unlock(m[j]); 864 } 865 VM_OBJECT_UNLOCK(object); 866 } else { 867 if (runpg < (count - first)) { 868 VM_OBJECT_LOCK(object); 869 for (i = first + runpg; i < count; i++) { 870 vm_page_lock(m[i]); 871 vm_page_free(m[i]); 872 vm_page_unlock(m[i]); 873 } 874 VM_OBJECT_UNLOCK(object); 875 count = first + runpg; 876 } 877 break; 878 } 879 first = runend; 880 } 881 882 /* 883 * the first and last page have been calculated now, move input pages 884 * to be zero based... 885 */ 886 if (first != 0) { 887 m += first; 888 count -= first; 889 reqpage -= first; 890 } 891 892 /* 893 * calculate the file virtual address for the transfer 894 */ 895 foff = IDX_TO_OFF(m[0]->pindex); 896 897 /* 898 * calculate the size of the transfer 899 */ 900 size = count * PAGE_SIZE; 901 KASSERT(count > 0, ("zero count")); 902 if ((foff + size) > object->un_pager.vnp.vnp_size) 903 size = object->un_pager.vnp.vnp_size - foff; 904 KASSERT(size > 0, ("zero size")); 905 906 /* 907 * round up physical size for real devices. 908 */ 909 if (1) { 910 int secmask = bo->bo_bsize - 1; 911 KASSERT(secmask < PAGE_SIZE && secmask > 0, 912 ("vnode_pager_generic_getpages: sector size %d too large", 913 secmask + 1)); 914 size = (size + secmask) & ~secmask; 915 } 916 917 bp = getpbuf(&vnode_pbuf_freecnt); 918 kva = (vm_offset_t)bp->b_data; 919 920 /* 921 * and map the pages to be read into the kva, if the filesystem 922 * requires mapped buffers. 923 */ 924 mp = vp->v_mount; 925 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 926 unmapped_buf_allowed) { 927 bp->b_data = unmapped_buf; 928 bp->b_kvabase = unmapped_buf; 929 bp->b_offset = 0; 930 bp->b_flags |= B_UNMAPPED; 931 bp->b_npages = count; 932 for (i = 0; i < count; i++) 933 bp->b_pages[i] = m[i]; 934 } else 935 pmap_qenter(kva, m, count); 936 937 /* build a minimal buffer header */ 938 bp->b_iocmd = BIO_READ; 939 bp->b_iodone = bdone; 940 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 941 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 942 bp->b_rcred = crhold(curthread->td_ucred); 943 bp->b_wcred = crhold(curthread->td_ucred); 944 bp->b_blkno = firstaddr; 945 pbgetbo(bo, bp); 946 bp->b_vp = vp; 947 bp->b_bcount = size; 948 bp->b_bufsize = size; 949 bp->b_runningbufspace = bp->b_bufsize; 950 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 951 952 PCPU_INC(cnt.v_vnodein); 953 PCPU_ADD(cnt.v_vnodepgsin, count); 954 955 /* do the input */ 956 bp->b_iooffset = dbtob(bp->b_blkno); 957 bstrategy(bp); 958 959 bwait(bp, PVM, "vnread"); 960 961 if ((bp->b_ioflags & BIO_ERROR) != 0) 962 error = EIO; 963 964 if (error == 0 && size != count * PAGE_SIZE) { 965 if ((bp->b_flags & B_UNMAPPED) != 0) { 966 bp->b_flags &= ~B_UNMAPPED; 967 pmap_qenter(kva, m, count); 968 } 969 bzero((caddr_t)kva + size, PAGE_SIZE * count - size); 970 } 971 if ((bp->b_flags & B_UNMAPPED) == 0) 972 pmap_qremove(kva, count); 973 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0) { 974 bp->b_data = (caddr_t)kva; 975 bp->b_kvabase = (caddr_t)kva; 976 bp->b_flags &= ~B_UNMAPPED; 977 for (i = 0; i < count; i++) 978 bp->b_pages[i] = NULL; 979 } 980 981 /* 982 * free the buffer header back to the swap buffer pool 983 */ 984 bp->b_vp = NULL; 985 pbrelbo(bp); 986 relpbuf(bp, &vnode_pbuf_freecnt); 987 988 VM_OBJECT_LOCK(object); 989 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 990 vm_page_t mt; 991 992 nextoff = tfoff + PAGE_SIZE; 993 mt = m[i]; 994 995 if (nextoff <= object->un_pager.vnp.vnp_size) { 996 /* 997 * Read filled up entire page. 998 */ 999 mt->valid = VM_PAGE_BITS_ALL; 1000 KASSERT(mt->dirty == 0, 1001 ("vnode_pager_generic_getpages: page %p is dirty", 1002 mt)); 1003 KASSERT(!pmap_page_is_mapped(mt), 1004 ("vnode_pager_generic_getpages: page %p is mapped", 1005 mt)); 1006 } else { 1007 /* 1008 * Read did not fill up entire page. 1009 * 1010 * Currently we do not set the entire page valid, 1011 * we just try to clear the piece that we couldn't 1012 * read. 1013 */ 1014 vm_page_set_valid(mt, 0, 1015 object->un_pager.vnp.vnp_size - tfoff); 1016 KASSERT((mt->dirty & vm_page_bits(0, 1017 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1018 ("vnode_pager_generic_getpages: page %p is dirty", 1019 mt)); 1020 } 1021 1022 if (i != reqpage) 1023 vm_page_readahead_finish(mt); 1024 } 1025 VM_OBJECT_UNLOCK(object); 1026 if (error) { 1027 printf("vnode_pager_getpages: I/O read error\n"); 1028 } 1029 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 1030 } 1031 1032 /* 1033 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1034 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1035 * vnode_pager_generic_putpages() to implement the previous behaviour. 1036 * 1037 * All other FS's should use the bypass to get to the local media 1038 * backing vp's VOP_PUTPAGES. 1039 */ 1040 static void 1041 vnode_pager_putpages(object, m, count, sync, rtvals) 1042 vm_object_t object; 1043 vm_page_t *m; 1044 int count; 1045 boolean_t sync; 1046 int *rtvals; 1047 { 1048 int rtval; 1049 struct vnode *vp; 1050 int bytes = count * PAGE_SIZE; 1051 1052 /* 1053 * Force synchronous operation if we are extremely low on memory 1054 * to prevent a low-memory deadlock. VOP operations often need to 1055 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1056 * operation ). The swapper handles the case by limiting the amount 1057 * of asynchronous I/O, but that sort of solution doesn't scale well 1058 * for the vnode pager without a lot of work. 1059 * 1060 * Also, the backing vnode's iodone routine may not wake the pageout 1061 * daemon up. This should be probably be addressed XXX. 1062 */ 1063 1064 if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) 1065 sync |= OBJPC_SYNC; 1066 1067 /* 1068 * Call device-specific putpages function 1069 */ 1070 vp = object->handle; 1071 VM_OBJECT_UNLOCK(object); 1072 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 1073 KASSERT(rtval != EOPNOTSUPP, 1074 ("vnode_pager: stale FS putpages\n")); 1075 VM_OBJECT_LOCK(object); 1076 } 1077 1078 1079 /* 1080 * This is now called from local media FS's to operate against their 1081 * own vnodes if they fail to implement VOP_PUTPAGES. 1082 * 1083 * This is typically called indirectly via the pageout daemon and 1084 * clustering has already typically occured, so in general we ask the 1085 * underlying filesystem to write the data out asynchronously rather 1086 * then delayed. 1087 */ 1088 int 1089 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1090 int flags, int *rtvals) 1091 { 1092 int i; 1093 vm_object_t object; 1094 vm_page_t m; 1095 int count; 1096 1097 int maxsize, ncount; 1098 vm_ooffset_t poffset; 1099 struct uio auio; 1100 struct iovec aiov; 1101 int error; 1102 int ioflags; 1103 int ppscheck = 0; 1104 static struct timeval lastfail; 1105 static int curfail; 1106 1107 object = vp->v_object; 1108 count = bytecount / PAGE_SIZE; 1109 1110 for (i = 0; i < count; i++) 1111 rtvals[i] = VM_PAGER_ERROR; 1112 1113 if ((int64_t)ma[0]->pindex < 0) { 1114 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1115 (long)ma[0]->pindex, (u_long)ma[0]->dirty); 1116 rtvals[0] = VM_PAGER_BAD; 1117 return VM_PAGER_BAD; 1118 } 1119 1120 maxsize = count * PAGE_SIZE; 1121 ncount = count; 1122 1123 poffset = IDX_TO_OFF(ma[0]->pindex); 1124 1125 /* 1126 * If the page-aligned write is larger then the actual file we 1127 * have to invalidate pages occuring beyond the file EOF. However, 1128 * there is an edge case where a file may not be page-aligned where 1129 * the last page is partially invalid. In this case the filesystem 1130 * may not properly clear the dirty bits for the entire page (which 1131 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1132 * With the page locked we are free to fix-up the dirty bits here. 1133 * 1134 * We do not under any circumstances truncate the valid bits, as 1135 * this will screw up bogus page replacement. 1136 */ 1137 VM_OBJECT_LOCK(object); 1138 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1139 if (object->un_pager.vnp.vnp_size > poffset) { 1140 int pgoff; 1141 1142 maxsize = object->un_pager.vnp.vnp_size - poffset; 1143 ncount = btoc(maxsize); 1144 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1145 /* 1146 * If the object is locked and the following 1147 * conditions hold, then the page's dirty 1148 * field cannot be concurrently changed by a 1149 * pmap operation. 1150 */ 1151 m = ma[ncount - 1]; 1152 KASSERT(m->busy > 0, 1153 ("vnode_pager_generic_putpages: page %p is not busy", m)); 1154 KASSERT(!pmap_page_is_write_mapped(m), 1155 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1156 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1157 pgoff); 1158 } 1159 } else { 1160 maxsize = 0; 1161 ncount = 0; 1162 } 1163 if (ncount < count) { 1164 for (i = ncount; i < count; i++) { 1165 rtvals[i] = VM_PAGER_BAD; 1166 } 1167 } 1168 } 1169 VM_OBJECT_UNLOCK(object); 1170 1171 /* 1172 * pageouts are already clustered, use IO_ASYNC t o force a bawrite() 1173 * rather then a bdwrite() to prevent paging I/O from saturating 1174 * the buffer cache. Dummy-up the sequential heuristic to cause 1175 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1176 * the system decides how to cluster. 1177 */ 1178 ioflags = IO_VMIO; 1179 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1180 ioflags |= IO_SYNC; 1181 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1182 ioflags |= IO_ASYNC; 1183 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1184 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1185 1186 aiov.iov_base = (caddr_t) 0; 1187 aiov.iov_len = maxsize; 1188 auio.uio_iov = &aiov; 1189 auio.uio_iovcnt = 1; 1190 auio.uio_offset = poffset; 1191 auio.uio_segflg = UIO_NOCOPY; 1192 auio.uio_rw = UIO_WRITE; 1193 auio.uio_resid = maxsize; 1194 auio.uio_td = (struct thread *) 0; 1195 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1196 PCPU_INC(cnt.v_vnodeout); 1197 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1198 1199 if (error) { 1200 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1201 printf("vnode_pager_putpages: I/O error %d\n", error); 1202 } 1203 if (auio.uio_resid) { 1204 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1205 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1206 auio.uio_resid, (u_long)ma[0]->pindex); 1207 } 1208 for (i = 0; i < ncount; i++) { 1209 rtvals[i] = VM_PAGER_OK; 1210 } 1211 return rtvals[0]; 1212 } 1213 1214 void 1215 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1216 { 1217 vm_object_t obj; 1218 int i, pos; 1219 1220 if (written == 0) 1221 return; 1222 obj = ma[0]->object; 1223 VM_OBJECT_LOCK(obj); 1224 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1225 if (pos < trunc_page(written)) { 1226 rtvals[i] = VM_PAGER_OK; 1227 vm_page_undirty(ma[i]); 1228 } else { 1229 /* Partially written page. */ 1230 rtvals[i] = VM_PAGER_AGAIN; 1231 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1232 } 1233 } 1234 VM_OBJECT_UNLOCK(obj); 1235 } 1236 1237 void 1238 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1239 vm_offset_t end) 1240 { 1241 struct vnode *vp; 1242 vm_ooffset_t old_wm; 1243 1244 VM_OBJECT_LOCK(object); 1245 if (object->type != OBJT_VNODE) { 1246 VM_OBJECT_UNLOCK(object); 1247 return; 1248 } 1249 old_wm = object->un_pager.vnp.writemappings; 1250 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1251 vp = object->handle; 1252 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1253 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1254 VOP_ADD_WRITECOUNT(vp, 1); 1255 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1256 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1257 VOP_ADD_WRITECOUNT(vp, -1); 1258 } 1259 VM_OBJECT_UNLOCK(object); 1260 } 1261 1262 void 1263 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1264 vm_offset_t end) 1265 { 1266 struct vnode *vp; 1267 struct mount *mp; 1268 vm_offset_t inc; 1269 int vfslocked; 1270 1271 VM_OBJECT_LOCK(object); 1272 1273 /* 1274 * First, recheck the object type to account for the race when 1275 * the vnode is reclaimed. 1276 */ 1277 if (object->type != OBJT_VNODE) { 1278 VM_OBJECT_UNLOCK(object); 1279 return; 1280 } 1281 1282 /* 1283 * Optimize for the case when writemappings is not going to 1284 * zero. 1285 */ 1286 inc = end - start; 1287 if (object->un_pager.vnp.writemappings != inc) { 1288 object->un_pager.vnp.writemappings -= inc; 1289 VM_OBJECT_UNLOCK(object); 1290 return; 1291 } 1292 1293 vp = object->handle; 1294 vhold(vp); 1295 VM_OBJECT_UNLOCK(object); 1296 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1297 mp = NULL; 1298 vn_start_write(vp, &mp, V_WAIT); 1299 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1300 1301 /* 1302 * Decrement the object's writemappings, by swapping the start 1303 * and end arguments for vnode_pager_update_writecount(). If 1304 * there was not a race with vnode reclaimation, then the 1305 * vnode's v_writecount is decremented. 1306 */ 1307 vnode_pager_update_writecount(object, end, start); 1308 VOP_UNLOCK(vp, 0); 1309 vdrop(vp); 1310 if (mp != NULL) 1311 vn_finished_write(mp); 1312 VFS_UNLOCK_GIANT(vfslocked); 1313 }
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