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 "opt_vm.h" 57 58#include <sys/param.h> 59#include <sys/systm.h> 60#include <sys/proc.h> 61#include <sys/vnode.h> 62#include <sys/mount.h> 63#include <sys/bio.h> 64#include <sys/buf.h> 65#include <sys/vmmeter.h> 66#include <sys/limits.h> 67#include <sys/conf.h> 68#include <sys/rwlock.h> 69#include <sys/sf_buf.h> 70 71#include <machine/atomic.h> 72 73#include <vm/vm.h> 74#include <vm/vm_param.h> 75#include <vm/vm_object.h> 76#include <vm/vm_page.h> 77#include <vm/vm_pager.h> 78#include <vm/vm_map.h> 79#include <vm/vnode_pager.h> 80#include <vm/vm_extern.h> 81 82static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 83 daddr_t *rtaddress, int *run); 84static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 85static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 86static void vnode_pager_dealloc(vm_object_t); 87static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 88static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *, 89 int *, vop_getpages_iodone_t, void *); 90static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 91static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 92static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 93 vm_ooffset_t, struct ucred *cred); 94static int vnode_pager_generic_getpages_done(struct buf *); 95static void vnode_pager_generic_getpages_done_async(struct buf *); 96 97struct pagerops vnodepagerops = { 98 .pgo_alloc = vnode_pager_alloc, 99 .pgo_dealloc = vnode_pager_dealloc, 100 .pgo_getpages = vnode_pager_getpages, 101 .pgo_getpages_async = vnode_pager_getpages_async, 102 .pgo_putpages = vnode_pager_putpages, 103 .pgo_haspage = vnode_pager_haspage, 104}; 105 106int vnode_pbuf_freecnt; 107int vnode_async_pbuf_freecnt; 108 109/* Create the VM system backing object for this vnode */ 110int 111vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 112{ 113 vm_object_t object; 114 vm_ooffset_t size = isize; 115 struct vattr va; 116 117 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 118 return (0); 119 120 while ((object = vp->v_object) != NULL) { 121 VM_OBJECT_WLOCK(object); 122 if (!(object->flags & OBJ_DEAD)) { 123 VM_OBJECT_WUNLOCK(object); 124 return (0); 125 } 126 VOP_UNLOCK(vp, 0); 127 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 128 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0); 129 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 130 } 131 132 if (size == 0) { 133 if (vn_isdisk(vp, NULL)) { 134 size = IDX_TO_OFF(INT_MAX); 135 } else { 136 if (VOP_GETATTR(vp, &va, td->td_ucred)) 137 return (0); 138 size = va.va_size; 139 } 140 } 141 142 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 143 /* 144 * Dereference the reference we just created. This assumes 145 * that the object is associated with the vp. 146 */ 147 VM_OBJECT_WLOCK(object); 148 object->ref_count--; 149 VM_OBJECT_WUNLOCK(object); 150 vrele(vp); 151 152 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 153 154 return (0); 155} 156 157void 158vnode_destroy_vobject(struct vnode *vp) 159{ 160 struct vm_object *obj; 161 162 obj = vp->v_object; 163 if (obj == NULL) 164 return; 165 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 166 VM_OBJECT_WLOCK(obj); 167 umtx_shm_object_terminated(obj); 168 if (obj->ref_count == 0) { 169 /* 170 * don't double-terminate the object 171 */ 172 if ((obj->flags & OBJ_DEAD) == 0) { 173 vm_object_terminate(obj); 174 } else { 175 /* 176 * Waiters were already handled during object 177 * termination. The exclusive vnode lock hopefully 178 * prevented new waiters from referencing the dying 179 * object. 180 */ 181 KASSERT((obj->flags & OBJ_DISCONNECTWNT) == 0, 182 ("OBJ_DISCONNECTWNT set obj %p flags %x", 183 obj, obj->flags)); 184 vp->v_object = NULL; 185 VM_OBJECT_WUNLOCK(obj); 186 } 187 } else { 188 /* 189 * Woe to the process that tries to page now :-). 190 */ 191 vm_pager_deallocate(obj); 192 VM_OBJECT_WUNLOCK(obj); 193 } 194 KASSERT(vp->v_object == NULL, ("vp %p obj %p", vp, vp->v_object)); 195} 196 197 198/* 199 * Allocate (or lookup) pager for a vnode. 200 * Handle is a vnode pointer. 201 * 202 * MPSAFE 203 */ 204vm_object_t 205vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 206 vm_ooffset_t offset, struct ucred *cred) 207{ 208 vm_object_t object; 209 struct vnode *vp; 210 211 /* 212 * Pageout to vnode, no can do yet. 213 */ 214 if (handle == NULL) 215 return (NULL); 216 217 vp = (struct vnode *) handle; 218 219 /* 220 * If the object is being terminated, wait for it to 221 * go away. 222 */ 223retry: 224 while ((object = vp->v_object) != NULL) { 225 VM_OBJECT_WLOCK(object); 226 if ((object->flags & OBJ_DEAD) == 0) 227 break; 228 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 229 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0); 230 } 231 232 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference")); 233 234 if (object == NULL) { 235 /* 236 * Add an object of the appropriate size 237 */ 238 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 239 240 object->un_pager.vnp.vnp_size = size; 241 object->un_pager.vnp.writemappings = 0; 242 243 object->handle = handle; 244 VI_LOCK(vp); 245 if (vp->v_object != NULL) { 246 /* 247 * Object has been created while we were sleeping 248 */ 249 VI_UNLOCK(vp); 250 VM_OBJECT_WLOCK(object); 251 KASSERT(object->ref_count == 1, 252 ("leaked ref %p %d", object, object->ref_count)); 253 object->type = OBJT_DEAD; 254 object->ref_count = 0; 255 VM_OBJECT_WUNLOCK(object); 256 vm_object_destroy(object); 257 goto retry; 258 } 259 vp->v_object = object; 260 VI_UNLOCK(vp); 261 } else { 262 object->ref_count++; 263#if VM_NRESERVLEVEL > 0 264 vm_object_color(object, 0); 265#endif 266 VM_OBJECT_WUNLOCK(object); 267 } 268 vref(vp); 269 return (object); 270} 271 272/* 273 * The object must be locked. 274 */ 275static void 276vnode_pager_dealloc(vm_object_t object) 277{ 278 struct vnode *vp; 279 int refs; 280 281 vp = object->handle; 282 if (vp == NULL) 283 panic("vnode_pager_dealloc: pager already dealloced"); 284 285 VM_OBJECT_ASSERT_WLOCKED(object); 286 vm_object_pip_wait(object, "vnpdea"); 287 refs = object->ref_count; 288 289 object->handle = NULL; 290 object->type = OBJT_DEAD; 291 if (object->flags & OBJ_DISCONNECTWNT) { 292 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 293 wakeup(object); 294 } 295 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 296 if (object->un_pager.vnp.writemappings > 0) { 297 object->un_pager.vnp.writemappings = 0; 298 VOP_ADD_WRITECOUNT(vp, -1); 299 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 300 __func__, vp, vp->v_writecount); 301 } 302 vp->v_object = NULL; 303 VOP_UNSET_TEXT(vp); 304 VM_OBJECT_WUNLOCK(object); 305 while (refs-- > 0) 306 vunref(vp); 307 VM_OBJECT_WLOCK(object); 308} 309 310static boolean_t 311vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 312 int *after) 313{ 314 struct vnode *vp = object->handle; 315 daddr_t bn; 316 int err; 317 daddr_t reqblock; 318 int poff; 319 int bsize; 320 int pagesperblock, blocksperpage; 321 322 VM_OBJECT_ASSERT_WLOCKED(object); 323 /* 324 * If no vp or vp is doomed or marked transparent to VM, we do not 325 * have the page. 326 */ 327 if (vp == NULL || vp->v_iflag & VI_DOOMED) 328 return FALSE; 329 /* 330 * If the offset is beyond end of file we do 331 * not have the page. 332 */ 333 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 334 return FALSE; 335 336 bsize = vp->v_mount->mnt_stat.f_iosize; 337 pagesperblock = bsize / PAGE_SIZE; 338 blocksperpage = 0; 339 if (pagesperblock > 0) { 340 reqblock = pindex / pagesperblock; 341 } else { 342 blocksperpage = (PAGE_SIZE / bsize); 343 reqblock = pindex * blocksperpage; 344 } 345 VM_OBJECT_WUNLOCK(object); 346 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 347 VM_OBJECT_WLOCK(object); 348 if (err) 349 return TRUE; 350 if (bn == -1) 351 return FALSE; 352 if (pagesperblock > 0) { 353 poff = pindex - (reqblock * pagesperblock); 354 if (before) { 355 *before *= pagesperblock; 356 *before += poff; 357 } 358 if (after) { 359 /* 360 * The BMAP vop can report a partial block in the 361 * 'after', but must not report blocks after EOF. 362 * Assert the latter, and truncate 'after' in case 363 * of the former. 364 */ 365 KASSERT((reqblock + *after) * pagesperblock < 366 roundup2(object->size, pagesperblock), 367 ("%s: reqblock %jd after %d size %ju", __func__, 368 (intmax_t )reqblock, *after, 369 (uintmax_t )object->size)); 370 *after *= pagesperblock; 371 *after += pagesperblock - (poff + 1); 372 if (pindex + *after >= object->size) 373 *after = object->size - 1 - pindex; 374 } 375 } else { 376 if (before) { 377 *before /= blocksperpage; 378 } 379 380 if (after) { 381 *after /= blocksperpage; 382 } 383 } 384 return TRUE; 385} 386 387/* 388 * Lets the VM system know about a change in size for a file. 389 * We adjust our own internal size and flush any cached pages in 390 * the associated object that are affected by the size change. 391 * 392 * Note: this routine may be invoked as a result of a pager put 393 * operation (possibly at object termination time), so we must be careful. 394 */ 395void 396vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 397{ 398 vm_object_t object; 399 vm_page_t m; 400 vm_pindex_t nobjsize; 401 402 if ((object = vp->v_object) == NULL) 403 return; 404/* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 405 VM_OBJECT_WLOCK(object); 406 if (object->type == OBJT_DEAD) { 407 VM_OBJECT_WUNLOCK(object); 408 return; 409 } 410 KASSERT(object->type == OBJT_VNODE, 411 ("not vnode-backed object %p", object)); 412 if (nsize == object->un_pager.vnp.vnp_size) { 413 /* 414 * Hasn't changed size 415 */ 416 VM_OBJECT_WUNLOCK(object); 417 return; 418 } 419 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 420 if (nsize < object->un_pager.vnp.vnp_size) { 421 /* 422 * File has shrunk. Toss any cached pages beyond the new EOF. 423 */ 424 if (nobjsize < object->size) 425 vm_object_page_remove(object, nobjsize, object->size, 426 0); 427 /* 428 * this gets rid of garbage at the end of a page that is now 429 * only partially backed by the vnode. 430 * 431 * XXX for some reason (I don't know yet), if we take a 432 * completely invalid page and mark it partially valid 433 * it can screw up NFS reads, so we don't allow the case. 434 */ 435 if ((nsize & PAGE_MASK) && 436 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 437 m->valid != 0) { 438 int base = (int)nsize & PAGE_MASK; 439 int size = PAGE_SIZE - base; 440 441 /* 442 * Clear out partial-page garbage in case 443 * the page has been mapped. 444 */ 445 pmap_zero_page_area(m, base, size); 446 447 /* 448 * Update the valid bits to reflect the blocks that 449 * have been zeroed. Some of these valid bits may 450 * have already been set. 451 */ 452 vm_page_set_valid_range(m, base, size); 453 454 /* 455 * Round "base" to the next block boundary so that the 456 * dirty bit for a partially zeroed block is not 457 * cleared. 458 */ 459 base = roundup2(base, DEV_BSIZE); 460 461 /* 462 * Clear out partial-page dirty bits. 463 * 464 * note that we do not clear out the valid 465 * bits. This would prevent bogus_page 466 * replacement from working properly. 467 */ 468 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 469 } else if ((nsize & PAGE_MASK) && 470 vm_page_is_cached(object, OFF_TO_IDX(nsize))) { 471 vm_page_cache_free(object, OFF_TO_IDX(nsize), 472 nobjsize); 473 } 474 } 475 object->un_pager.vnp.vnp_size = nsize; 476 object->size = nobjsize; 477 VM_OBJECT_WUNLOCK(object); 478} 479 480/* 481 * calculate the linear (byte) disk address of specified virtual 482 * file address 483 */ 484static int 485vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 486 int *run) 487{ 488 int bsize; 489 int err; 490 daddr_t vblock; 491 daddr_t voffset; 492 493 if (address < 0) 494 return -1; 495 496 if (vp->v_iflag & VI_DOOMED) 497 return -1; 498 499 bsize = vp->v_mount->mnt_stat.f_iosize; 500 vblock = address / bsize; 501 voffset = address % bsize; 502 503 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 504 if (err == 0) { 505 if (*rtaddress != -1) 506 *rtaddress += voffset / DEV_BSIZE; 507 if (run) { 508 *run += 1; 509 *run *= bsize/PAGE_SIZE; 510 *run -= voffset/PAGE_SIZE; 511 } 512 } 513 514 return (err); 515} 516 517/* 518 * small block filesystem vnode pager input 519 */ 520static int 521vnode_pager_input_smlfs(vm_object_t object, vm_page_t m) 522{ 523 struct vnode *vp; 524 struct bufobj *bo; 525 struct buf *bp; 526 struct sf_buf *sf; 527 daddr_t fileaddr; 528 vm_offset_t bsize; 529 vm_page_bits_t bits; 530 int error, i; 531 532 error = 0; 533 vp = object->handle; 534 if (vp->v_iflag & VI_DOOMED) 535 return VM_PAGER_BAD; 536 537 bsize = vp->v_mount->mnt_stat.f_iosize; 538 539 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 540 541 sf = sf_buf_alloc(m, 0); 542 543 for (i = 0; i < PAGE_SIZE / bsize; i++) { 544 vm_ooffset_t address; 545 546 bits = vm_page_bits(i * bsize, bsize); 547 if (m->valid & bits) 548 continue; 549 550 address = IDX_TO_OFF(m->pindex) + i * bsize; 551 if (address >= object->un_pager.vnp.vnp_size) { 552 fileaddr = -1; 553 } else { 554 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 555 if (error) 556 break; 557 } 558 if (fileaddr != -1) { 559 bp = getpbuf(&vnode_pbuf_freecnt); 560 561 /* build a minimal buffer header */ 562 bp->b_iocmd = BIO_READ; 563 bp->b_iodone = bdone; 564 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 565 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 566 bp->b_rcred = crhold(curthread->td_ucred); 567 bp->b_wcred = crhold(curthread->td_ucred); 568 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 569 bp->b_blkno = fileaddr; 570 pbgetbo(bo, bp); 571 bp->b_vp = vp; 572 bp->b_bcount = bsize; 573 bp->b_bufsize = bsize; 574 bp->b_runningbufspace = bp->b_bufsize; 575 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 576 577 /* do the input */ 578 bp->b_iooffset = dbtob(bp->b_blkno); 579 bstrategy(bp); 580 581 bwait(bp, PVM, "vnsrd"); 582 583 if ((bp->b_ioflags & BIO_ERROR) != 0) 584 error = EIO; 585 586 /* 587 * free the buffer header back to the swap buffer pool 588 */ 589 bp->b_vp = NULL; 590 pbrelbo(bp); 591 relpbuf(bp, &vnode_pbuf_freecnt); 592 if (error) 593 break; 594 } else 595 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 596 KASSERT((m->dirty & bits) == 0, 597 ("vnode_pager_input_smlfs: page %p is dirty", m)); 598 VM_OBJECT_WLOCK(object); 599 m->valid |= bits; 600 VM_OBJECT_WUNLOCK(object); 601 } 602 sf_buf_free(sf); 603 if (error) { 604 return VM_PAGER_ERROR; 605 } 606 return VM_PAGER_OK; 607} 608 609/* 610 * old style vnode pager input routine 611 */ 612static int 613vnode_pager_input_old(vm_object_t object, vm_page_t m) 614{ 615 struct uio auio; 616 struct iovec aiov; 617 int error; 618 int size; 619 struct sf_buf *sf; 620 struct vnode *vp; 621 622 VM_OBJECT_ASSERT_WLOCKED(object); 623 error = 0; 624 625 /* 626 * Return failure if beyond current EOF 627 */ 628 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 629 return VM_PAGER_BAD; 630 } else { 631 size = PAGE_SIZE; 632 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 633 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 634 vp = object->handle; 635 VM_OBJECT_WUNLOCK(object); 636 637 /* 638 * Allocate a kernel virtual address and initialize so that 639 * we can use VOP_READ/WRITE routines. 640 */ 641 sf = sf_buf_alloc(m, 0); 642 643 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 644 aiov.iov_len = size; 645 auio.uio_iov = &aiov; 646 auio.uio_iovcnt = 1; 647 auio.uio_offset = IDX_TO_OFF(m->pindex); 648 auio.uio_segflg = UIO_SYSSPACE; 649 auio.uio_rw = UIO_READ; 650 auio.uio_resid = size; 651 auio.uio_td = curthread; 652 653 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 654 if (!error) { 655 int count = size - auio.uio_resid; 656 657 if (count == 0) 658 error = EINVAL; 659 else if (count != PAGE_SIZE) 660 bzero((caddr_t)sf_buf_kva(sf) + count, 661 PAGE_SIZE - count); 662 } 663 sf_buf_free(sf); 664 665 VM_OBJECT_WLOCK(object); 666 } 667 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 668 if (!error) 669 m->valid = VM_PAGE_BITS_ALL; 670 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 671} 672 673/* 674 * generic vnode pager input routine 675 */ 676 677/* 678 * Local media VFS's that do not implement their own VOP_GETPAGES 679 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 680 * to implement the previous behaviour. 681 * 682 * All other FS's should use the bypass to get to the local media 683 * backing vp's VOP_GETPAGES. 684 */ 685static int 686vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 687 int *rahead) 688{ 689 struct vnode *vp; 690 int rtval; 691 692 vp = object->handle; 693 VM_OBJECT_WUNLOCK(object); 694 rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead); 695 KASSERT(rtval != EOPNOTSUPP, 696 ("vnode_pager: FS getpages not implemented\n")); 697 VM_OBJECT_WLOCK(object); 698 return rtval; 699} 700 701static int 702vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count, 703 int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg) 704{ 705 struct vnode *vp; 706 int rtval; 707 708 vp = object->handle; 709 VM_OBJECT_WUNLOCK(object); 710 rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg); 711 KASSERT(rtval != EOPNOTSUPP, 712 ("vnode_pager: FS getpages_async not implemented\n")); 713 VM_OBJECT_WLOCK(object); 714 return (rtval); 715} 716 717/* 718 * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for 719 * local filesystems, where partially valid pages can only occur at 720 * the end of file. 721 */ 722int 723vnode_pager_local_getpages(struct vop_getpages_args *ap) 724{ 725 726 return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, 727 ap->a_rbehind, ap->a_rahead, NULL, NULL)); 728} 729 730int 731vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap) 732{ 733 734 return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, 735 ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg)); 736} 737 738/* 739 * This is now called from local media FS's to operate against their 740 * own vnodes if they fail to implement VOP_GETPAGES. 741 */ 742int 743vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count, 744 int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg) 745{ 746 vm_object_t object; 747 struct bufobj *bo; 748 struct buf *bp; 749 off_t foff; 750 int bsize, pagesperblock, *freecnt; 751 int error, before, after, rbehind, rahead, poff, i; 752 int bytecount, secmask; 753 754 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 755 ("%s does not support devices", __func__)); 756 757 if (vp->v_iflag & VI_DOOMED) 758 return (VM_PAGER_BAD); 759 760 object = vp->v_object; 761 foff = IDX_TO_OFF(m[0]->pindex); 762 bsize = vp->v_mount->mnt_stat.f_iosize; 763 pagesperblock = bsize / PAGE_SIZE; 764 765 KASSERT(foff < object->un_pager.vnp.vnp_size, 766 ("%s: page %p offset beyond vp %p size", __func__, m[0], vp)); 767 KASSERT(count <= sizeof(bp->b_pages), 768 ("%s: requested %d pages", __func__, count)); 769 770 /* 771 * The last page has valid blocks. Invalid part can only 772 * exist at the end of file, and the page is made fully valid 773 * by zeroing in vm_pager_get_pages(). 774 */ 775 if (m[count - 1]->valid != 0 && --count == 0) { 776 if (iodone != NULL) 777 iodone(arg, m, 1, 0); 778 return (VM_PAGER_OK); 779 } 780 781 /* 782 * Synchronous and asynchronous paging operations use different 783 * free pbuf counters. This is done to avoid asynchronous requests 784 * to consume all pbufs. 785 * Allocate the pbuf at the very beginning of the function, so that 786 * if we are low on certain kind of pbufs don't even proceed to BMAP, 787 * but sleep. 788 */ 789 freecnt = iodone != NULL ? 790 &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt; 791 bp = getpbuf(freecnt); 792 793 /* 794 * Get the underlying device blocks for the file with VOP_BMAP(). 795 * If the file system doesn't support VOP_BMAP, use old way of 796 * getting pages via VOP_READ. 797 */ 798 error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before); 799 if (error == EOPNOTSUPP) { 800 relpbuf(bp, freecnt); 801 VM_OBJECT_WLOCK(object); 802 for (i = 0; i < count; i++) { 803 PCPU_INC(cnt.v_vnodein); 804 PCPU_INC(cnt.v_vnodepgsin); 805 error = vnode_pager_input_old(object, m[i]); 806 if (error) 807 break; 808 } 809 VM_OBJECT_WUNLOCK(object); 810 return (error); 811 } else if (error != 0) { 812 relpbuf(bp, freecnt); 813 return (VM_PAGER_ERROR); 814 } 815 816 /* 817 * If the file system supports BMAP, but blocksize is smaller 818 * than a page size, then use special small filesystem code. 819 */ 820 if (pagesperblock == 0) { 821 relpbuf(bp, freecnt); 822 for (i = 0; i < count; i++) { 823 PCPU_INC(cnt.v_vnodein); 824 PCPU_INC(cnt.v_vnodepgsin); 825 error = vnode_pager_input_smlfs(object, m[i]); 826 if (error) 827 break; 828 } 829 return (error); 830 } 831 832 /* 833 * A sparse file can be encountered only for a single page request, 834 * which may not be preceded by call to vm_pager_haspage(). 835 */ 836 if (bp->b_blkno == -1) { 837 KASSERT(count == 1, 838 ("%s: array[%d] request to a sparse file %p", __func__, 839 count, vp)); 840 relpbuf(bp, freecnt); 841 pmap_zero_page(m[0]); 842 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty", 843 __func__, m[0])); 844 VM_OBJECT_WLOCK(object); 845 m[0]->valid = VM_PAGE_BITS_ALL; 846 VM_OBJECT_WUNLOCK(object); 847 return (VM_PAGER_OK); 848 } 849 850 bp->b_blkno += (foff % bsize) / DEV_BSIZE; 851 852 /* Recalculate blocks available after/before to pages. */ 853 poff = (foff % bsize) / PAGE_SIZE; 854 before *= pagesperblock; 855 before += poff; 856 after *= pagesperblock; 857 after += pagesperblock - (poff + 1); 858 if (m[0]->pindex + after >= object->size) 859 after = object->size - 1 - m[0]->pindex; 860 KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d", 861 __func__, count, after + 1)); 862 after -= count - 1; 863 864 /* Trim requested rbehind/rahead to possible values. */ 865 rbehind = a_rbehind ? *a_rbehind : 0; 866 rahead = a_rahead ? *a_rahead : 0; 867 rbehind = min(rbehind, before); 868 rbehind = min(rbehind, m[0]->pindex); 869 rahead = min(rahead, after); 870 rahead = min(rahead, object->size - m[count - 1]->pindex); 871 KASSERT(rbehind + rahead + count <= sizeof(bp->b_pages), 872 ("%s: behind %d ahead %d count %d", __func__, 873 rbehind, rahead, count)); 874 875 /* 876 * Fill in the bp->b_pages[] array with requested and optional 877 * read behind or read ahead pages. Read behind pages are looked 878 * up in a backward direction, down to a first cached page. Same 879 * for read ahead pages, but there is no need to shift the array 880 * in case of encountering a cached page. 881 */ 882 i = bp->b_npages = 0; 883 if (rbehind) { 884 vm_pindex_t startpindex, tpindex; 885 vm_page_t p; 886 887 VM_OBJECT_WLOCK(object); 888 startpindex = m[0]->pindex - rbehind; 889 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL && 890 p->pindex >= startpindex) 891 startpindex = p->pindex + 1; 892 893 /* tpindex is unsigned; beware of numeric underflow. */ 894 for (tpindex = m[0]->pindex - 1; 895 tpindex >= startpindex && tpindex < m[0]->pindex; 896 tpindex--, i++) { 897 p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL | 898 VM_ALLOC_IFNOTCACHED); 899 if (p == NULL) { 900 /* Shift the array. */ 901 for (int j = 0; j < i; j++) 902 bp->b_pages[j] = bp->b_pages[j + 903 tpindex + 1 - startpindex]; 904 break; 905 } 906 bp->b_pages[tpindex - startpindex] = p; 907 } 908 909 bp->b_pgbefore = i; 910 bp->b_npages += i; 911 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE; 912 } else 913 bp->b_pgbefore = 0; 914 915 /* Requested pages. */ 916 for (int j = 0; j < count; j++, i++) 917 bp->b_pages[i] = m[j]; 918 bp->b_npages += count; 919 920 if (rahead) { 921 vm_pindex_t endpindex, tpindex; 922 vm_page_t p; 923 924 if (!VM_OBJECT_WOWNED(object)) 925 VM_OBJECT_WLOCK(object); 926 endpindex = m[count - 1]->pindex + rahead + 1; 927 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL && 928 p->pindex < endpindex) 929 endpindex = p->pindex; 930 if (endpindex > object->size) 931 endpindex = object->size; 932 933 for (tpindex = m[count - 1]->pindex + 1; 934 tpindex < endpindex; i++, tpindex++) { 935 p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL | 936 VM_ALLOC_IFNOTCACHED); 937 if (p == NULL) 938 break; 939 bp->b_pages[i] = p; 940 } 941 942 bp->b_pgafter = i - bp->b_npages; 943 bp->b_npages = i; 944 } else 945 bp->b_pgafter = 0; 946 947 if (VM_OBJECT_WOWNED(object)) 948 VM_OBJECT_WUNLOCK(object); 949 950 /* Report back actual behind/ahead read. */ 951 if (a_rbehind) 952 *a_rbehind = bp->b_pgbefore; 953 if (a_rahead) 954 *a_rahead = bp->b_pgafter; 955 956 KASSERT(bp->b_npages <= sizeof(bp->b_pages), 957 ("%s: buf %p overflowed", __func__, bp)); 958 959 /* 960 * Recalculate first offset and bytecount with regards to read behind. 961 * Truncate bytecount to vnode real size and round up physical size 962 * for real devices. 963 */ 964 foff = IDX_TO_OFF(bp->b_pages[0]->pindex); 965 bytecount = bp->b_npages << PAGE_SHIFT; 966 if ((foff + bytecount) > object->un_pager.vnp.vnp_size) 967 bytecount = object->un_pager.vnp.vnp_size - foff; 968 secmask = bo->bo_bsize - 1; 969 KASSERT(secmask < PAGE_SIZE && secmask > 0, 970 ("%s: sector size %d too large", __func__, secmask + 1)); 971 bytecount = (bytecount + secmask) & ~secmask; 972 973 /* 974 * And map the pages to be read into the kva, if the filesystem 975 * requires mapped buffers. 976 */ 977 if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 978 unmapped_buf_allowed) { 979 bp->b_data = unmapped_buf; 980 bp->b_offset = 0; 981 } else { 982 bp->b_data = bp->b_kvabase; 983 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 984 } 985 986 /* Build a minimal buffer header. */ 987 bp->b_iocmd = BIO_READ; 988 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 989 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 990 bp->b_rcred = crhold(curthread->td_ucred); 991 bp->b_wcred = crhold(curthread->td_ucred); 992 pbgetbo(bo, bp); 993 bp->b_vp = vp; 994 bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount; 995 bp->b_iooffset = dbtob(bp->b_blkno); 996 997 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 998 PCPU_INC(cnt.v_vnodein); 999 PCPU_ADD(cnt.v_vnodepgsin, bp->b_npages); 1000 1001 if (iodone != NULL) { /* async */ 1002 bp->b_pgiodone = iodone; 1003 bp->b_caller1 = arg; 1004 bp->b_iodone = vnode_pager_generic_getpages_done_async; 1005 bp->b_flags |= B_ASYNC; 1006 BUF_KERNPROC(bp); 1007 bstrategy(bp); 1008 return (VM_PAGER_OK); 1009 } else { 1010 bp->b_iodone = bdone; 1011 bstrategy(bp); 1012 bwait(bp, PVM, "vnread"); 1013 error = vnode_pager_generic_getpages_done(bp); 1014 for (i = 0; i < bp->b_npages; i++) 1015 bp->b_pages[i] = NULL; 1016 bp->b_vp = NULL; 1017 pbrelbo(bp); 1018 relpbuf(bp, &vnode_pbuf_freecnt); 1019 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 1020 } 1021} 1022 1023static void 1024vnode_pager_generic_getpages_done_async(struct buf *bp) 1025{ 1026 int error; 1027 1028 error = vnode_pager_generic_getpages_done(bp); 1029 /* Run the iodone upon the requested range. */ 1030 bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore, 1031 bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error); 1032 for (int i = 0; i < bp->b_npages; i++) 1033 bp->b_pages[i] = NULL; 1034 bp->b_vp = NULL; 1035 pbrelbo(bp); 1036 relpbuf(bp, &vnode_async_pbuf_freecnt); 1037} 1038 1039static int 1040vnode_pager_generic_getpages_done(struct buf *bp) 1041{ 1042 vm_object_t object; 1043 off_t tfoff, nextoff; 1044 int i, error; 1045 1046 error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0; 1047 object = bp->b_vp->v_object; 1048 1049 if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) { 1050 if (!buf_mapped(bp)) { 1051 bp->b_data = bp->b_kvabase; 1052 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, 1053 bp->b_npages); 1054 } 1055 bzero(bp->b_data + bp->b_bcount, 1056 PAGE_SIZE * bp->b_npages - bp->b_bcount); 1057 } 1058 if (buf_mapped(bp)) { 1059 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages); 1060 bp->b_data = unmapped_buf; 1061 } 1062 1063 VM_OBJECT_WLOCK(object); 1064 for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex); 1065 i < bp->b_npages; i++, tfoff = nextoff) { 1066 vm_page_t mt; 1067 1068 nextoff = tfoff + PAGE_SIZE; 1069 mt = bp->b_pages[i]; 1070 1071 if (nextoff <= object->un_pager.vnp.vnp_size) { 1072 /* 1073 * Read filled up entire page. 1074 */ 1075 mt->valid = VM_PAGE_BITS_ALL; 1076 KASSERT(mt->dirty == 0, 1077 ("%s: page %p is dirty", __func__, mt)); 1078 KASSERT(!pmap_page_is_mapped(mt), 1079 ("%s: page %p is mapped", __func__, mt)); 1080 } else { 1081 /* 1082 * Read did not fill up entire page. 1083 * 1084 * Currently we do not set the entire page valid, 1085 * we just try to clear the piece that we couldn't 1086 * read. 1087 */ 1088 vm_page_set_valid_range(mt, 0, 1089 object->un_pager.vnp.vnp_size - tfoff); 1090 KASSERT((mt->dirty & vm_page_bits(0, 1091 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1092 ("%s: page %p is dirty", __func__, mt)); 1093 } 1094 1095 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter) 1096 vm_page_readahead_finish(mt); 1097 } 1098 VM_OBJECT_WUNLOCK(object); 1099 if (error != 0) 1100 printf("%s: I/O read error %d\n", __func__, error); 1101 1102 return (error); 1103} 1104 1105/* 1106 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1107 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1108 * vnode_pager_generic_putpages() to implement the previous behaviour. 1109 * 1110 * All other FS's should use the bypass to get to the local media 1111 * backing vp's VOP_PUTPAGES. 1112 */ 1113static void 1114vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 1115 int flags, int *rtvals) 1116{ 1117 int rtval; 1118 struct vnode *vp; 1119 int bytes = count * PAGE_SIZE; 1120 1121 /* 1122 * Force synchronous operation if we are extremely low on memory 1123 * to prevent a low-memory deadlock. VOP operations often need to 1124 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1125 * operation ). The swapper handles the case by limiting the amount 1126 * of asynchronous I/O, but that sort of solution doesn't scale well 1127 * for the vnode pager without a lot of work. 1128 * 1129 * Also, the backing vnode's iodone routine may not wake the pageout 1130 * daemon up. This should be probably be addressed XXX. 1131 */ 1132 1133 if (vm_cnt.v_free_count + vm_cnt.v_cache_count < 1134 vm_cnt.v_pageout_free_min) 1135 flags |= VM_PAGER_PUT_SYNC; 1136 1137 /* 1138 * Call device-specific putpages function 1139 */ 1140 vp = object->handle; 1141 VM_OBJECT_WUNLOCK(object); 1142 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals); 1143 KASSERT(rtval != EOPNOTSUPP, 1144 ("vnode_pager: stale FS putpages\n")); 1145 VM_OBJECT_WLOCK(object); 1146} 1147 1148 1149/* 1150 * This is now called from local media FS's to operate against their 1151 * own vnodes if they fail to implement VOP_PUTPAGES. 1152 * 1153 * This is typically called indirectly via the pageout daemon and 1154 * clustering has already typically occurred, so in general we ask the 1155 * underlying filesystem to write the data out asynchronously rather 1156 * then delayed. 1157 */ 1158int 1159vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1160 int flags, int *rtvals) 1161{ 1162 int i; 1163 vm_object_t object; 1164 vm_page_t m; 1165 int count; 1166 1167 int maxsize, ncount; 1168 vm_ooffset_t poffset; 1169 struct uio auio; 1170 struct iovec aiov; 1171 int error; 1172 int ioflags; 1173 int ppscheck = 0; 1174 static struct timeval lastfail; 1175 static int curfail; 1176 1177 object = vp->v_object; 1178 count = bytecount / PAGE_SIZE; 1179 1180 for (i = 0; i < count; i++) 1181 rtvals[i] = VM_PAGER_ERROR; 1182 1183 if ((int64_t)ma[0]->pindex < 0) { 1184 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n", 1185 (long)ma[0]->pindex, (u_long)ma[0]->dirty); 1186 rtvals[0] = VM_PAGER_BAD; 1187 return VM_PAGER_BAD; 1188 } 1189 1190 maxsize = count * PAGE_SIZE; 1191 ncount = count; 1192 1193 poffset = IDX_TO_OFF(ma[0]->pindex); 1194 1195 /* 1196 * If the page-aligned write is larger then the actual file we 1197 * have to invalidate pages occurring beyond the file EOF. However, 1198 * there is an edge case where a file may not be page-aligned where 1199 * the last page is partially invalid. In this case the filesystem 1200 * may not properly clear the dirty bits for the entire page (which 1201 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1202 * With the page locked we are free to fix-up the dirty bits here. 1203 * 1204 * We do not under any circumstances truncate the valid bits, as 1205 * this will screw up bogus page replacement. 1206 */ 1207 VM_OBJECT_WLOCK(object); 1208 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1209 if (object->un_pager.vnp.vnp_size > poffset) { 1210 int pgoff; 1211 1212 maxsize = object->un_pager.vnp.vnp_size - poffset; 1213 ncount = btoc(maxsize); 1214 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1215 /* 1216 * If the object is locked and the following 1217 * conditions hold, then the page's dirty 1218 * field cannot be concurrently changed by a 1219 * pmap operation. 1220 */ 1221 m = ma[ncount - 1]; 1222 vm_page_assert_sbusied(m); 1223 KASSERT(!pmap_page_is_write_mapped(m), 1224 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1225 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1226 pgoff); 1227 } 1228 } else { 1229 maxsize = 0; 1230 ncount = 0; 1231 } 1232 if (ncount < count) { 1233 for (i = ncount; i < count; i++) { 1234 rtvals[i] = VM_PAGER_BAD; 1235 } 1236 } 1237 } 1238 VM_OBJECT_WUNLOCK(object); 1239 1240 /* 1241 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 1242 * rather then a bdwrite() to prevent paging I/O from saturating 1243 * the buffer cache. Dummy-up the sequential heuristic to cause 1244 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 1245 * the system decides how to cluster. 1246 */ 1247 ioflags = IO_VMIO; 1248 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 1249 ioflags |= IO_SYNC; 1250 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 1251 ioflags |= IO_ASYNC; 1252 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 1253 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1254 1255 aiov.iov_base = (caddr_t) 0; 1256 aiov.iov_len = maxsize; 1257 auio.uio_iov = &aiov; 1258 auio.uio_iovcnt = 1; 1259 auio.uio_offset = poffset; 1260 auio.uio_segflg = UIO_NOCOPY; 1261 auio.uio_rw = UIO_WRITE; 1262 auio.uio_resid = maxsize; 1263 auio.uio_td = (struct thread *) 0; 1264 error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); 1265 PCPU_INC(cnt.v_vnodeout); 1266 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1267 1268 if (error) { 1269 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1))) 1270 printf("vnode_pager_putpages: I/O error %d\n", error); 1271 } 1272 if (auio.uio_resid) { 1273 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1)) 1274 printf("vnode_pager_putpages: residual I/O %zd at %lu\n", 1275 auio.uio_resid, (u_long)ma[0]->pindex); 1276 } 1277 for (i = 0; i < ncount; i++) { 1278 rtvals[i] = VM_PAGER_OK; 1279 } 1280 return rtvals[0]; 1281} 1282 1283void 1284vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1285{ 1286 vm_object_t obj; 1287 int i, pos; 1288 1289 if (written == 0) 1290 return; 1291 obj = ma[0]->object; 1292 VM_OBJECT_WLOCK(obj); 1293 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1294 if (pos < trunc_page(written)) { 1295 rtvals[i] = VM_PAGER_OK; 1296 vm_page_undirty(ma[i]); 1297 } else { 1298 /* Partially written page. */ 1299 rtvals[i] = VM_PAGER_AGAIN; 1300 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1301 } 1302 } 1303 VM_OBJECT_WUNLOCK(obj); 1304} 1305 1306void 1307vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1308 vm_offset_t end) 1309{ 1310 struct vnode *vp; 1311 vm_ooffset_t old_wm; 1312 1313 VM_OBJECT_WLOCK(object); 1314 if (object->type != OBJT_VNODE) { 1315 VM_OBJECT_WUNLOCK(object); 1316 return; 1317 } 1318 old_wm = object->un_pager.vnp.writemappings; 1319 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1320 vp = object->handle; 1321 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1322 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1323 VOP_ADD_WRITECOUNT(vp, 1); 1324 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1325 __func__, vp, vp->v_writecount); 1326 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1327 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1328 VOP_ADD_WRITECOUNT(vp, -1); 1329 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1330 __func__, vp, vp->v_writecount); 1331 } 1332 VM_OBJECT_WUNLOCK(object); 1333} 1334 1335void 1336vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1337 vm_offset_t end) 1338{ 1339 struct vnode *vp; 1340 struct mount *mp; 1341 vm_offset_t inc; 1342 1343 VM_OBJECT_WLOCK(object); 1344 1345 /* 1346 * First, recheck the object type to account for the race when 1347 * the vnode is reclaimed. 1348 */ 1349 if (object->type != OBJT_VNODE) { 1350 VM_OBJECT_WUNLOCK(object); 1351 return; 1352 } 1353 1354 /* 1355 * Optimize for the case when writemappings is not going to 1356 * zero. 1357 */ 1358 inc = end - start; 1359 if (object->un_pager.vnp.writemappings != inc) { 1360 object->un_pager.vnp.writemappings -= inc; 1361 VM_OBJECT_WUNLOCK(object); 1362 return; 1363 } 1364 1365 vp = object->handle; 1366 vhold(vp); 1367 VM_OBJECT_WUNLOCK(object); 1368 mp = NULL; 1369 vn_start_write(vp, &mp, V_WAIT); 1370 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1371 1372 /* 1373 * Decrement the object's writemappings, by swapping the start 1374 * and end arguments for vnode_pager_update_writecount(). If 1375 * there was not a race with vnode reclaimation, then the 1376 * vnode's v_writecount is decremented. 1377 */ 1378 vnode_pager_update_writecount(object, end, start); 1379 VOP_UNLOCK(vp, 0); 1380 vdrop(vp); 1381 if (mp != NULL) 1382 vn_finished_write(mp); 1383} 1384