vnode_pager.c revision 284100
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: stable/10/sys/vm/vnode_pager.c 284100 2015-06-06 20:37:40Z jhb $"); 55 56#include <sys/param.h> 57#include <sys/systm.h> 58#include <sys/proc.h> 59#include <sys/vnode.h> 60#include <sys/mount.h> 61#include <sys/bio.h> 62#include <sys/buf.h> 63#include <sys/vmmeter.h> 64#include <sys/limits.h> 65#include <sys/conf.h> 66#include <sys/rwlock.h> 67#include <sys/sf_buf.h> 68 69#include <machine/atomic.h> 70 71#include <vm/vm.h> 72#include <vm/vm_param.h> 73#include <vm/vm_object.h> 74#include <vm/vm_page.h> 75#include <vm/vm_pager.h> 76#include <vm/vm_map.h> 77#include <vm/vnode_pager.h> 78#include <vm/vm_extern.h> 79 80static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 81 daddr_t *rtaddress, int *run); 82static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 83static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 84static void vnode_pager_dealloc(vm_object_t); 85static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); 86static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 87static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 88static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 89 vm_ooffset_t, struct ucred *cred); 90 91struct pagerops vnodepagerops = { 92 .pgo_alloc = vnode_pager_alloc, 93 .pgo_dealloc = vnode_pager_dealloc, 94 .pgo_getpages = vnode_pager_getpages, 95 .pgo_putpages = vnode_pager_putpages, 96 .pgo_haspage = vnode_pager_haspage, 97}; 98 99int vnode_pbuf_freecnt; 100 101/* Create the VM system backing object for this vnode */ 102int 103vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 104{ 105 vm_object_t object; 106 vm_ooffset_t size = isize; 107 struct vattr va; 108 109 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 110 return (0); 111 112 while ((object = vp->v_object) != NULL) { 113 VM_OBJECT_WLOCK(object); 114 if (!(object->flags & OBJ_DEAD)) { 115 VM_OBJECT_WUNLOCK(object); 116 return (0); 117 } 118 VOP_UNLOCK(vp, 0); 119 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 120 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0); 121 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 122 } 123 124 if (size == 0) { 125 if (vn_isdisk(vp, NULL)) { 126 size = IDX_TO_OFF(INT_MAX); 127 } else { 128 if (VOP_GETATTR(vp, &va, td->td_ucred)) 129 return (0); 130 size = va.va_size; 131 } 132 } 133 134 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 135 /* 136 * Dereference the reference we just created. This assumes 137 * that the object is associated with the vp. 138 */ 139 VM_OBJECT_WLOCK(object); 140 object->ref_count--; 141 VM_OBJECT_WUNLOCK(object); 142 vrele(vp); 143 144 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 145 146 return (0); 147} 148 149void 150vnode_destroy_vobject(struct vnode *vp) 151{ 152 struct vm_object *obj; 153 154 obj = vp->v_object; 155 if (obj == NULL) 156 return; 157 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 158 VM_OBJECT_WLOCK(obj); 159 if (obj->ref_count == 0) { 160 /* 161 * don't double-terminate the object 162 */ 163 if ((obj->flags & OBJ_DEAD) == 0) 164 vm_object_terminate(obj); 165 else 166 VM_OBJECT_WUNLOCK(obj); 167 } else { 168 /* 169 * Woe to the process that tries to page now :-). 170 */ 171 vm_pager_deallocate(obj); 172 VM_OBJECT_WUNLOCK(obj); 173 } 174 vp->v_object = NULL; 175} 176 177 178/* 179 * Allocate (or lookup) pager for a vnode. 180 * Handle is a vnode pointer. 181 * 182 * MPSAFE 183 */ 184vm_object_t 185vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 186 vm_ooffset_t offset, struct ucred *cred) 187{ 188 vm_object_t object; 189 struct vnode *vp; 190 191 /* 192 * Pageout to vnode, no can do yet. 193 */ 194 if (handle == NULL) 195 return (NULL); 196 197 vp = (struct vnode *) handle; 198 199 /* 200 * If the object is being terminated, wait for it to 201 * go away. 202 */ 203retry: 204 while ((object = vp->v_object) != NULL) { 205 VM_OBJECT_WLOCK(object); 206 if ((object->flags & OBJ_DEAD) == 0) 207 break; 208 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 209 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0); 210 } 211 212 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference")); 213 214 if (object == NULL) { 215 /* 216 * Add an object of the appropriate size 217 */ 218 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 219 220 object->un_pager.vnp.vnp_size = size; 221 object->un_pager.vnp.writemappings = 0; 222 223 object->handle = handle; 224 VI_LOCK(vp); 225 if (vp->v_object != NULL) { 226 /* 227 * Object has been created while we were sleeping 228 */ 229 VI_UNLOCK(vp); 230 VM_OBJECT_WLOCK(object); 231 KASSERT(object->ref_count == 1, 232 ("leaked ref %p %d", object, object->ref_count)); 233 object->type = OBJT_DEAD; 234 object->ref_count = 0; 235 VM_OBJECT_WUNLOCK(object); 236 vm_object_destroy(object); 237 goto retry; 238 } 239 vp->v_object = object; 240 VI_UNLOCK(vp); 241 } else { 242 object->ref_count++; 243 VM_OBJECT_WUNLOCK(object); 244 } 245 vref(vp); 246 return (object); 247} 248 249/* 250 * The object must be locked. 251 */ 252static void 253vnode_pager_dealloc(object) 254 vm_object_t object; 255{ 256 struct vnode *vp; 257 int refs; 258 259 vp = object->handle; 260 if (vp == NULL) 261 panic("vnode_pager_dealloc: pager already dealloced"); 262 263 VM_OBJECT_ASSERT_WLOCKED(object); 264 vm_object_pip_wait(object, "vnpdea"); 265 refs = object->ref_count; 266 267 object->handle = NULL; 268 object->type = OBJT_DEAD; 269 if (object->flags & OBJ_DISCONNECTWNT) { 270 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 271 wakeup(object); 272 } 273 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 274 if (object->un_pager.vnp.writemappings > 0) { 275 object->un_pager.vnp.writemappings = 0; 276 VOP_ADD_WRITECOUNT(vp, -1); 277 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 278 __func__, vp, vp->v_writecount); 279 } 280 vp->v_object = NULL; 281 VOP_UNSET_TEXT(vp); 282 VM_OBJECT_WUNLOCK(object); 283 while (refs-- > 0) 284 vunref(vp); 285 VM_OBJECT_WLOCK(object); 286} 287 288static boolean_t 289vnode_pager_haspage(object, pindex, before, after) 290 vm_object_t object; 291 vm_pindex_t pindex; 292 int *before; 293 int *after; 294{ 295 struct vnode *vp = object->handle; 296 daddr_t bn; 297 int err; 298 daddr_t reqblock; 299 int poff; 300 int bsize; 301 int pagesperblock, blocksperpage; 302 303 VM_OBJECT_ASSERT_WLOCKED(object); 304 /* 305 * If no vp or vp is doomed or marked transparent to VM, we do not 306 * have the page. 307 */ 308 if (vp == NULL || vp->v_iflag & VI_DOOMED) 309 return FALSE; 310 /* 311 * If the offset is beyond end of file we do 312 * not have the page. 313 */ 314 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 315 return FALSE; 316 317 bsize = vp->v_mount->mnt_stat.f_iosize; 318 pagesperblock = bsize / PAGE_SIZE; 319 blocksperpage = 0; 320 if (pagesperblock > 0) { 321 reqblock = pindex / pagesperblock; 322 } else { 323 blocksperpage = (PAGE_SIZE / bsize); 324 reqblock = pindex * blocksperpage; 325 } 326 VM_OBJECT_WUNLOCK(object); 327 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 328 VM_OBJECT_WLOCK(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 */ 371void 372vnode_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/* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 383 VM_OBJECT_WLOCK(object); 384 if (object->type == OBJT_DEAD) { 385 VM_OBJECT_WUNLOCK(object); 386 return; 387 } 388 KASSERT(object->type == OBJT_VNODE, 389 ("not vnode-backed object %p", object)); 390 if (nsize == object->un_pager.vnp.vnp_size) { 391 /* 392 * Hasn't changed size 393 */ 394 VM_OBJECT_WUNLOCK(object); 395 return; 396 } 397 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 398 if (nsize < object->un_pager.vnp.vnp_size) { 399 /* 400 * File has shrunk. Toss any cached pages beyond the new EOF. 401 */ 402 if (nobjsize < object->size) 403 vm_object_page_remove(object, nobjsize, object->size, 404 0); 405 /* 406 * this gets rid of garbage at the end of a page that is now 407 * only partially backed by the vnode. 408 * 409 * XXX for some reason (I don't know yet), if we take a 410 * completely invalid page and mark it partially valid 411 * it can screw up NFS reads, so we don't allow the case. 412 */ 413 if ((nsize & PAGE_MASK) && 414 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 415 m->valid != 0) { 416 int base = (int)nsize & PAGE_MASK; 417 int size = PAGE_SIZE - base; 418 419 /* 420 * Clear out partial-page garbage in case 421 * the page has been mapped. 422 */ 423 pmap_zero_page_area(m, base, size); 424 425 /* 426 * Update the valid bits to reflect the blocks that 427 * have been zeroed. Some of these valid bits may 428 * have already been set. 429 */ 430 vm_page_set_valid_range(m, base, size); 431 432 /* 433 * Round "base" to the next block boundary so that the 434 * dirty bit for a partially zeroed block is not 435 * cleared. 436 */ 437 base = roundup2(base, DEV_BSIZE); 438 439 /* 440 * Clear out partial-page dirty bits. 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_clear_dirty(m, base, PAGE_SIZE - base); 447 } else if ((nsize & PAGE_MASK) && 448 vm_page_is_cached(object, OFF_TO_IDX(nsize))) { 449 vm_page_cache_free(object, OFF_TO_IDX(nsize), 450 nobjsize); 451 } 452 } 453 object->un_pager.vnp.vnp_size = nsize; 454 object->size = nobjsize; 455 VM_OBJECT_WUNLOCK(object); 456} 457 458/* 459 * calculate the linear (byte) disk address of specified virtual 460 * file address 461 */ 462static int 463vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 464 int *run) 465{ 466 int bsize; 467 int err; 468 daddr_t vblock; 469 daddr_t voffset; 470 471 if (address < 0) 472 return -1; 473 474 if (vp->v_iflag & VI_DOOMED) 475 return -1; 476 477 bsize = vp->v_mount->mnt_stat.f_iosize; 478 vblock = address / bsize; 479 voffset = address % bsize; 480 481 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 482 if (err == 0) { 483 if (*rtaddress != -1) 484 *rtaddress += voffset / DEV_BSIZE; 485 if (run) { 486 *run += 1; 487 *run *= bsize/PAGE_SIZE; 488 *run -= voffset/PAGE_SIZE; 489 } 490 } 491 492 return (err); 493} 494 495/* 496 * small block filesystem vnode pager input 497 */ 498static int 499vnode_pager_input_smlfs(object, m) 500 vm_object_t object; 501 vm_page_t m; 502{ 503 struct vnode *vp; 504 struct bufobj *bo; 505 struct buf *bp; 506 struct sf_buf *sf; 507 daddr_t fileaddr; 508 vm_offset_t bsize; 509 vm_page_bits_t bits; 510 int error, i; 511 512 error = 0; 513 vp = object->handle; 514 if (vp->v_iflag & VI_DOOMED) 515 return VM_PAGER_BAD; 516 517 bsize = vp->v_mount->mnt_stat.f_iosize; 518 519 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 520 521 sf = sf_buf_alloc(m, 0); 522 523 for (i = 0; i < PAGE_SIZE / bsize; i++) { 524 vm_ooffset_t address; 525 526 bits = vm_page_bits(i * bsize, bsize); 527 if (m->valid & bits) 528 continue; 529 530 address = IDX_TO_OFF(m->pindex) + i * bsize; 531 if (address >= object->un_pager.vnp.vnp_size) { 532 fileaddr = -1; 533 } else { 534 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 535 if (error) 536 break; 537 } 538 if (fileaddr != -1) { 539 bp = getpbuf(&vnode_pbuf_freecnt); 540 541 /* build a minimal buffer header */ 542 bp->b_iocmd = BIO_READ; 543 bp->b_iodone = bdone; 544 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 545 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 546 bp->b_rcred = crhold(curthread->td_ucred); 547 bp->b_wcred = crhold(curthread->td_ucred); 548 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 549 bp->b_blkno = fileaddr; 550 pbgetbo(bo, bp); 551 bp->b_vp = vp; 552 bp->b_bcount = bsize; 553 bp->b_bufsize = bsize; 554 bp->b_runningbufspace = bp->b_bufsize; 555 atomic_add_long(&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 bp->b_vp = NULL; 570 pbrelbo(bp); 571 relpbuf(bp, &vnode_pbuf_freecnt); 572 if (error) 573 break; 574 } else 575 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 576 KASSERT((m->dirty & bits) == 0, 577 ("vnode_pager_input_smlfs: page %p is dirty", m)); 578 VM_OBJECT_WLOCK(object); 579 m->valid |= bits; 580 VM_OBJECT_WUNLOCK(object); 581 } 582 sf_buf_free(sf); 583 if (error) { 584 return VM_PAGER_ERROR; 585 } 586 return VM_PAGER_OK; 587} 588 589/* 590 * old style vnode pager input routine 591 */ 592static int 593vnode_pager_input_old(object, m) 594 vm_object_t object; 595 vm_page_t m; 596{ 597 struct uio auio; 598 struct iovec aiov; 599 int error; 600 int size; 601 struct sf_buf *sf; 602 struct vnode *vp; 603 604 VM_OBJECT_ASSERT_WLOCKED(object); 605 error = 0; 606 607 /* 608 * Return failure if beyond current EOF 609 */ 610 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 611 return VM_PAGER_BAD; 612 } else { 613 size = PAGE_SIZE; 614 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 615 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 616 vp = object->handle; 617 VM_OBJECT_WUNLOCK(object); 618 619 /* 620 * Allocate a kernel virtual address and initialize so that 621 * we can use VOP_READ/WRITE routines. 622 */ 623 sf = sf_buf_alloc(m, 0); 624 625 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 626 aiov.iov_len = size; 627 auio.uio_iov = &aiov; 628 auio.uio_iovcnt = 1; 629 auio.uio_offset = IDX_TO_OFF(m->pindex); 630 auio.uio_segflg = UIO_SYSSPACE; 631 auio.uio_rw = UIO_READ; 632 auio.uio_resid = size; 633 auio.uio_td = curthread; 634 635 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 636 if (!error) { 637 int count = size - auio.uio_resid; 638 639 if (count == 0) 640 error = EINVAL; 641 else if (count != PAGE_SIZE) 642 bzero((caddr_t)sf_buf_kva(sf) + count, 643 PAGE_SIZE - count); 644 } 645 sf_buf_free(sf); 646 647 VM_OBJECT_WLOCK(object); 648 } 649 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 650 if (!error) 651 m->valid = VM_PAGE_BITS_ALL; 652 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 653} 654 655/* 656 * generic vnode pager input routine 657 */ 658 659/* 660 * Local media VFS's that do not implement their own VOP_GETPAGES 661 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 662 * to implement the previous behaviour. 663 * 664 * All other FS's should use the bypass to get to the local media 665 * backing vp's VOP_GETPAGES. 666 */ 667static int 668vnode_pager_getpages(object, m, count, reqpage) 669 vm_object_t object; 670 vm_page_t *m; 671 int count; 672 int reqpage; 673{ 674 int rtval; 675 struct vnode *vp; 676 int bytes = count * PAGE_SIZE; 677 678 vp = object->handle; 679 VM_OBJECT_WUNLOCK(object); 680 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 681 KASSERT(rtval != EOPNOTSUPP, 682 ("vnode_pager: FS getpages not implemented\n")); 683 VM_OBJECT_WLOCK(object); 684 return rtval; 685} 686 687/* 688 * This is now called from local media FS's to operate against their 689 * own vnodes if they fail to implement VOP_GETPAGES. 690 */ 691int 692vnode_pager_generic_getpages(vp, m, bytecount, reqpage) 693 struct vnode *vp; 694 vm_page_t *m; 695 int bytecount; 696 int reqpage; 697{ 698 vm_object_t object; 699 vm_offset_t kva; 700 off_t foff, tfoff, nextoff; 701 int i, j, size, bsize, first; 702 daddr_t firstaddr, reqblock; 703 struct bufobj *bo; 704 int runpg; 705 int runend; 706 struct buf *bp; 707 struct mount *mp; 708 int count; 709 int error; 710 711 object = vp->v_object; 712 count = bytecount / PAGE_SIZE; 713 714 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 715 ("vnode_pager_generic_getpages does not support devices")); 716 if (vp->v_iflag & VI_DOOMED) 717 return VM_PAGER_BAD; 718 719 bsize = vp->v_mount->mnt_stat.f_iosize; 720 721 /* get the UNDERLYING device for the file with VOP_BMAP() */ 722 723 /* 724 * originally, we did not check for an error return value -- assuming 725 * an fs always has a bmap entry point -- that assumption is wrong!!! 726 */ 727 foff = IDX_TO_OFF(m[reqpage]->pindex); 728 729 /* 730 * if we can't bmap, use old VOP code 731 */ 732 error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL); 733 if (error == EOPNOTSUPP) { 734 VM_OBJECT_WLOCK(object); 735 736 for (i = 0; i < count; i++) 737 if (i != reqpage) { 738 vm_page_lock(m[i]); 739 vm_page_free(m[i]); 740 vm_page_unlock(m[i]); 741 } 742 PCPU_INC(cnt.v_vnodein); 743 PCPU_INC(cnt.v_vnodepgsin); 744 error = vnode_pager_input_old(object, m[reqpage]); 745 VM_OBJECT_WUNLOCK(object); 746 return (error); 747 } else if (error != 0) { 748 VM_OBJECT_WLOCK(object); 749 for (i = 0; i < count; i++) 750 if (i != reqpage) { 751 vm_page_lock(m[i]); 752 vm_page_free(m[i]); 753 vm_page_unlock(m[i]); 754 } 755 VM_OBJECT_WUNLOCK(object); 756 return (VM_PAGER_ERROR); 757 758 /* 759 * if the blocksize is smaller than a page size, then use 760 * special small filesystem code. NFS sometimes has a small 761 * blocksize, but it can handle large reads itself. 762 */ 763 } else if ((PAGE_SIZE / bsize) > 1 && 764 (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { 765 VM_OBJECT_WLOCK(object); 766 for (i = 0; i < count; i++) 767 if (i != reqpage) { 768 vm_page_lock(m[i]); 769 vm_page_free(m[i]); 770 vm_page_unlock(m[i]); 771 } 772 VM_OBJECT_WUNLOCK(object); 773 PCPU_INC(cnt.v_vnodein); 774 PCPU_INC(cnt.v_vnodepgsin); 775 return vnode_pager_input_smlfs(object, m[reqpage]); 776 } 777 778 /* 779 * If we have a completely valid page available to us, we can 780 * clean up and return. Otherwise we have to re-read the 781 * media. 782 */ 783 VM_OBJECT_WLOCK(object); 784 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 785 for (i = 0; i < count; i++) 786 if (i != reqpage) { 787 vm_page_lock(m[i]); 788 vm_page_free(m[i]); 789 vm_page_unlock(m[i]); 790 } 791 VM_OBJECT_WUNLOCK(object); 792 return VM_PAGER_OK; 793 } else if (reqblock == -1) { 794 pmap_zero_page(m[reqpage]); 795 KASSERT(m[reqpage]->dirty == 0, 796 ("vnode_pager_generic_getpages: page %p is dirty", m)); 797 m[reqpage]->valid = VM_PAGE_BITS_ALL; 798 for (i = 0; i < count; i++) 799 if (i != reqpage) { 800 vm_page_lock(m[i]); 801 vm_page_free(m[i]); 802 vm_page_unlock(m[i]); 803 } 804 VM_OBJECT_WUNLOCK(object); 805 return (VM_PAGER_OK); 806 } 807 m[reqpage]->valid = 0; 808 VM_OBJECT_WUNLOCK(object); 809 810 /* 811 * here on direct device I/O 812 */ 813 firstaddr = -1; 814 815 /* 816 * calculate the run that includes the required page 817 */ 818 for (first = 0, i = 0; i < count; i = runend) { 819 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr, 820 &runpg) != 0) { 821 VM_OBJECT_WLOCK(object); 822 for (; i < count; i++) 823 if (i != reqpage) { 824 vm_page_lock(m[i]); 825 vm_page_free(m[i]); 826 vm_page_unlock(m[i]); 827 } 828 VM_OBJECT_WUNLOCK(object); 829 return (VM_PAGER_ERROR); 830 } 831 if (firstaddr == -1) { 832 VM_OBJECT_WLOCK(object); 833 if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { 834 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", 835 (intmax_t)firstaddr, (uintmax_t)(foff >> 32), 836 (uintmax_t)foff, 837 (uintmax_t) 838 (object->un_pager.vnp.vnp_size >> 32), 839 (uintmax_t)object->un_pager.vnp.vnp_size); 840 } 841 vm_page_lock(m[i]); 842 vm_page_free(m[i]); 843 vm_page_unlock(m[i]); 844 VM_OBJECT_WUNLOCK(object); 845 runend = i + 1; 846 first = runend; 847 continue; 848 } 849 runend = i + runpg; 850 if (runend <= reqpage) { 851 VM_OBJECT_WLOCK(object); 852 for (j = i; j < runend; j++) { 853 vm_page_lock(m[j]); 854 vm_page_free(m[j]); 855 vm_page_unlock(m[j]); 856 } 857 VM_OBJECT_WUNLOCK(object); 858 } else { 859 if (runpg < (count - first)) { 860 VM_OBJECT_WLOCK(object); 861 for (i = first + runpg; i < count; i++) { 862 vm_page_lock(m[i]); 863 vm_page_free(m[i]); 864 vm_page_unlock(m[i]); 865 } 866 VM_OBJECT_WUNLOCK(object); 867 count = first + runpg; 868 } 869 break; 870 } 871 first = runend; 872 } 873 874 /* 875 * the first and last page have been calculated now, move input pages 876 * to be zero based... 877 */ 878 if (first != 0) { 879 m += first; 880 count -= first; 881 reqpage -= first; 882 } 883 884 /* 885 * calculate the file virtual address for the transfer 886 */ 887 foff = IDX_TO_OFF(m[0]->pindex); 888 889 /* 890 * calculate the size of the transfer 891 */ 892 size = count * PAGE_SIZE; 893 KASSERT(count > 0, ("zero count")); 894 if ((foff + size) > object->un_pager.vnp.vnp_size) 895 size = object->un_pager.vnp.vnp_size - foff; 896 KASSERT(size > 0, ("zero size")); 897 898 /* 899 * round up physical size for real devices. 900 */ 901 if (1) { 902 int secmask = bo->bo_bsize - 1; 903 KASSERT(secmask < PAGE_SIZE && secmask > 0, 904 ("vnode_pager_generic_getpages: sector size %d too large", 905 secmask + 1)); 906 size = (size + secmask) & ~secmask; 907 } 908 909 bp = getpbuf(&vnode_pbuf_freecnt); 910 kva = (vm_offset_t)bp->b_data; 911 912 /* 913 * and map the pages to be read into the kva, if the filesystem 914 * requires mapped buffers. 915 */ 916 mp = vp->v_mount; 917 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 918 unmapped_buf_allowed) { 919 bp->b_data = unmapped_buf; 920 bp->b_kvabase = unmapped_buf; 921 bp->b_offset = 0; 922 bp->b_flags |= B_UNMAPPED; 923 bp->b_npages = count; 924 for (i = 0; i < count; i++) 925 bp->b_pages[i] = m[i]; 926 } else 927 pmap_qenter(kva, m, count); 928 929 /* build a minimal buffer header */ 930 bp->b_iocmd = BIO_READ; 931 bp->b_iodone = bdone; 932 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 933 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 934 bp->b_rcred = crhold(curthread->td_ucred); 935 bp->b_wcred = crhold(curthread->td_ucred); 936 bp->b_blkno = firstaddr; 937 pbgetbo(bo, bp); 938 bp->b_vp = vp; 939 bp->b_bcount = size; 940 bp->b_bufsize = size; 941 bp->b_runningbufspace = bp->b_bufsize; 942 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 943 944 PCPU_INC(cnt.v_vnodein); 945 PCPU_ADD(cnt.v_vnodepgsin, count); 946 947 /* do the input */ 948 bp->b_iooffset = dbtob(bp->b_blkno); 949 bstrategy(bp); 950 951 bwait(bp, PVM, "vnread"); 952 953 if ((bp->b_ioflags & BIO_ERROR) != 0) 954 error = EIO; 955 956 if (error == 0 && size != count * PAGE_SIZE) { 957 if ((bp->b_flags & B_UNMAPPED) != 0) { 958 bp->b_flags &= ~B_UNMAPPED; 959 pmap_qenter(kva, m, count); 960 } 961 bzero((caddr_t)kva + size, PAGE_SIZE * count - size); 962 } 963 if ((bp->b_flags & B_UNMAPPED) == 0) 964 pmap_qremove(kva, count); 965 if (mp != NULL && (mp->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0) { 966 bp->b_data = (caddr_t)kva; 967 bp->b_kvabase = (caddr_t)kva; 968 bp->b_flags &= ~B_UNMAPPED; 969 for (i = 0; i < count; i++) 970 bp->b_pages[i] = NULL; 971 } 972 973 /* 974 * free the buffer header back to the swap buffer pool 975 */ 976 bp->b_vp = NULL; 977 pbrelbo(bp); 978 relpbuf(bp, &vnode_pbuf_freecnt); 979 980 VM_OBJECT_WLOCK(object); 981 for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { 982 vm_page_t mt; 983 984 nextoff = tfoff + PAGE_SIZE; 985 mt = m[i]; 986 987 if (nextoff <= object->un_pager.vnp.vnp_size) { 988 /* 989 * Read filled up entire page. 990 */ 991 mt->valid = VM_PAGE_BITS_ALL; 992 KASSERT(mt->dirty == 0, 993 ("vnode_pager_generic_getpages: page %p is dirty", 994 mt)); 995 KASSERT(!pmap_page_is_mapped(mt), 996 ("vnode_pager_generic_getpages: page %p is mapped", 997 mt)); 998 } else { 999 /* 1000 * Read did not fill up entire page. 1001 * 1002 * Currently we do not set the entire page valid, 1003 * we just try to clear the piece that we couldn't 1004 * read. 1005 */ 1006 vm_page_set_valid_range(mt, 0, 1007 object->un_pager.vnp.vnp_size - tfoff); 1008 KASSERT((mt->dirty & vm_page_bits(0, 1009 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1010 ("vnode_pager_generic_getpages: page %p is dirty", 1011 mt)); 1012 } 1013 1014 if (i != reqpage) 1015 vm_page_readahead_finish(mt); 1016 } 1017 VM_OBJECT_WUNLOCK(object); 1018 if (error) { 1019 printf("vnode_pager_getpages: I/O read error\n"); 1020 } 1021 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 1022} 1023 1024/* 1025 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1026 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1027 * vnode_pager_generic_putpages() to implement the previous behaviour. 1028 * 1029 * All other FS's should use the bypass to get to the local media 1030 * backing vp's VOP_PUTPAGES. 1031 */ 1032static void 1033vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 1034 int flags, int *rtvals) 1035{ 1036 int rtval; 1037 struct vnode *vp; 1038 int bytes = count * PAGE_SIZE; 1039 1040 /* 1041 * Force synchronous operation if we are extremely low on memory 1042 * to prevent a low-memory deadlock. VOP operations often need to 1043 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1044 * operation ). The swapper handles the case by limiting the amount 1045 * of asynchronous I/O, but that sort of solution doesn't scale well 1046 * for the vnode pager without a lot of work. 1047 * 1048 * Also, the backing vnode's iodone routine may not wake the pageout 1049 * daemon up. This should be probably be addressed XXX. 1050 */ 1051 1052 if (cnt.v_free_count + cnt.v_cache_count < cnt.v_pageout_free_min) 1053 flags |= VM_PAGER_PUT_SYNC; 1054 1055 /* 1056 * Call device-specific putpages function 1057 */ 1058 vp = object->handle; 1059 VM_OBJECT_WUNLOCK(object); 1060 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals, 0); 1061 KASSERT(rtval != EOPNOTSUPP, 1062 ("vnode_pager: stale FS putpages\n")); 1063 VM_OBJECT_WLOCK(object); 1064} 1065 1066 1067/* 1068 * This is now called from local media FS's to operate against their 1069 * own vnodes if they fail to implement VOP_PUTPAGES. 1070 * 1071 * This is typically called indirectly via the pageout daemon and 1072 * clustering has already typically occured, so in general we ask the 1073 * underlying filesystem to write the data out asynchronously rather 1074 * then delayed. 1075 */ 1076int 1077vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1078 int flags, int *rtvals) 1079{ 1080 int i; 1081 vm_object_t object; 1082 vm_page_t m; 1083 int count; 1084 1085 int maxsize, ncount; 1086 vm_ooffset_t poffset; 1087 struct uio auio; 1088 struct iovec aiov; 1089 int error; 1090 int ioflags; 1091 int ppscheck = 0; 1092 static struct timeval lastfail; 1093 static int curfail; 1094 1095 object = vp->v_object; 1096 count = bytecount / PAGE_SIZE; 1097 1098 for (i = 0; i < count; i++) 1099 rtvals[i] = VM_PAGER_ERROR; 1100 1101 if ((int64_t)ma[0]->pindex < 0) { 1102 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1103 (long)ma[0]->pindex, (u_long)ma[0]->dirty); 1104 rtvals[0] = VM_PAGER_BAD; 1105 return VM_PAGER_BAD; 1106 } 1107 1108 maxsize = count * PAGE_SIZE; 1109 ncount = count; 1110 1111 poffset = IDX_TO_OFF(ma[0]->pindex); 1112 1113 /* 1114 * If the page-aligned write is larger then the actual file we 1115 * have to invalidate pages occuring beyond the file EOF. However, 1116 * there is an edge case where a file may not be page-aligned where 1117 * the last page is partially invalid. In this case the filesystem 1118 * may not properly clear the dirty bits for the entire page (which 1119 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1120 * With the page locked we are free to fix-up the dirty bits here. 1121 * 1122 * We do not under any circumstances truncate the valid bits, as 1123 * this will screw up bogus page replacement. 1124 */ 1125 VM_OBJECT_WLOCK(object); 1126 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1127 if (object->un_pager.vnp.vnp_size > poffset) { 1128 int pgoff; 1129 1130 maxsize = object->un_pager.vnp.vnp_size - poffset; 1131 ncount = btoc(maxsize); 1132 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1133 /* 1134 * If the object is locked and the following 1135 * conditions hold, then the page's dirty 1136 * field cannot be concurrently changed by a 1137 * pmap operation. 1138 */ 1139 m = ma[ncount - 1]; 1140 vm_page_assert_sbusied(m); 1141 KASSERT(!pmap_page_is_write_mapped(m), 1142 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1143 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1144 pgoff); 1145 } 1146 } else { 1147 maxsize = 0; 1148 ncount = 0; 1149 } 1150 if (ncount < count) { 1151 for (i = ncount; i < count; i++) { 1152 rtvals[i] = VM_PAGER_BAD; 1153 } 1154 } 1155 } 1156 VM_OBJECT_WUNLOCK(object); 1157 1158 /* 1159 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 1160 * rather then a bdwrite() to prevent paging I/O from saturating 1161 * the buffer cache. Dummy-up the sequential heuristic to cause 1162 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1163 * the system decides how to cluster. 1164 */ 1165 ioflags = IO_VMIO; 1166 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1167 ioflags |= IO_SYNC; 1168 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1169 ioflags |= IO_ASYNC; 1170 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1171 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1172 1173 aiov.iov_base = (caddr_t) 0; 1174 aiov.iov_len = maxsize; 1175 auio.uio_iov = &aiov; 1176 auio.uio_iovcnt = 1; 1177 auio.uio_offset = poffset; 1178 auio.uio_segflg = UIO_NOCOPY; 1179 auio.uio_rw = UIO_WRITE; 1180 auio.uio_resid = maxsize; 1181 auio.uio_td = (struct thread *) 0; 1182 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1183 PCPU_INC(cnt.v_vnodeout); 1184 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1185 1186 if (error) { 1187 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1188 printf("vnode_pager_putpages: I/O error %d\n", error); 1189 } 1190 if (auio.uio_resid) { 1191 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1192 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1193 auio.uio_resid, (u_long)ma[0]->pindex); 1194 } 1195 for (i = 0; i < ncount; i++) { 1196 rtvals[i] = VM_PAGER_OK; 1197 } 1198 return rtvals[0]; 1199} 1200 1201void 1202vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1203{ 1204 vm_object_t obj; 1205 int i, pos; 1206 1207 if (written == 0) 1208 return; 1209 obj = ma[0]->object; 1210 VM_OBJECT_WLOCK(obj); 1211 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1212 if (pos < trunc_page(written)) { 1213 rtvals[i] = VM_PAGER_OK; 1214 vm_page_undirty(ma[i]); 1215 } else { 1216 /* Partially written page. */ 1217 rtvals[i] = VM_PAGER_AGAIN; 1218 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1219 } 1220 } 1221 VM_OBJECT_WUNLOCK(obj); 1222} 1223 1224void 1225vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1226 vm_offset_t end) 1227{ 1228 struct vnode *vp; 1229 vm_ooffset_t old_wm; 1230 1231 VM_OBJECT_WLOCK(object); 1232 if (object->type != OBJT_VNODE) { 1233 VM_OBJECT_WUNLOCK(object); 1234 return; 1235 } 1236 old_wm = object->un_pager.vnp.writemappings; 1237 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1238 vp = object->handle; 1239 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1240 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1241 VOP_ADD_WRITECOUNT(vp, 1); 1242 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1243 __func__, vp, vp->v_writecount); 1244 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1245 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1246 VOP_ADD_WRITECOUNT(vp, -1); 1247 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1248 __func__, vp, vp->v_writecount); 1249 } 1250 VM_OBJECT_WUNLOCK(object); 1251} 1252 1253void 1254vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1255 vm_offset_t end) 1256{ 1257 struct vnode *vp; 1258 struct mount *mp; 1259 vm_offset_t inc; 1260 1261 VM_OBJECT_WLOCK(object); 1262 1263 /* 1264 * First, recheck the object type to account for the race when 1265 * the vnode is reclaimed. 1266 */ 1267 if (object->type != OBJT_VNODE) { 1268 VM_OBJECT_WUNLOCK(object); 1269 return; 1270 } 1271 1272 /* 1273 * Optimize for the case when writemappings is not going to 1274 * zero. 1275 */ 1276 inc = end - start; 1277 if (object->un_pager.vnp.writemappings != inc) { 1278 object->un_pager.vnp.writemappings -= inc; 1279 VM_OBJECT_WUNLOCK(object); 1280 return; 1281 } 1282 1283 vp = object->handle; 1284 vhold(vp); 1285 VM_OBJECT_WUNLOCK(object); 1286 mp = NULL; 1287 vn_start_write(vp, &mp, V_WAIT); 1288 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1289 1290 /* 1291 * Decrement the object's writemappings, by swapping the start 1292 * and end arguments for vnode_pager_update_writecount(). If 1293 * there was not a race with vnode reclaimation, then the 1294 * vnode's v_writecount is decremented. 1295 */ 1296 vnode_pager_update_writecount(object, end, start); 1297 VOP_UNLOCK(vp, 0); 1298 vdrop(vp); 1299 if (mp != NULL) 1300 vn_finished_write(mp); 1301} 1302