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sys/vm/vnode_pager.c
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1 /*- 2 * Copyright (c) 1990 University of Utah. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * Copyright (c) 1993, 1994 John S. Dyson 6 * Copyright (c) 1995, David Greenman 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 41 */ 42 43 /* 44 * Page to/from files (vnodes). 45 */ 46 47 /* 48 * TODO: 49 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 50 * greatly re-simplify the vnode_pager. 51 */ 52 53 #include <sys/cdefs.h> 54 __FBSDID("$FreeBSD: releng/11.1/sys/vm/vnode_pager.c 320693 2017-07-05 19:24:53Z markj $"); 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 82 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 83 daddr_t *rtaddress, int *run); 84 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 85 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 86 static void vnode_pager_dealloc(vm_object_t); 87 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 88 static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *, 89 int *, vop_getpages_iodone_t, void *); 90 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 91 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 92 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 93 vm_ooffset_t, struct ucred *cred); 94 static int vnode_pager_generic_getpages_done(struct buf *); 95 static void vnode_pager_generic_getpages_done_async(struct buf *); 96 97 struct 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 }; 105 106 int vnode_pbuf_freecnt; 107 int vnode_async_pbuf_freecnt; 108 109 /* Create the VM system backing object for this vnode */ 110 int 111 vnode_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 } 156 157 void 158 vnode_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 */ 204 vm_object_t 205 vnode_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 */ 223 retry: 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 vrefact(vp); 269 return (object); 270 } 271 272 /* 273 * The object must be locked. 274 */ 275 static void 276 vnode_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 } 309 310 static boolean_t 311 vnode_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 */ 395 void 396 vnode_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 } 470 } 471 object->un_pager.vnp.vnp_size = nsize; 472 object->size = nobjsize; 473 VM_OBJECT_WUNLOCK(object); 474 } 475 476 /* 477 * calculate the linear (byte) disk address of specified virtual 478 * file address 479 */ 480 static int 481 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 482 int *run) 483 { 484 int bsize; 485 int err; 486 daddr_t vblock; 487 daddr_t voffset; 488 489 if (address < 0) 490 return -1; 491 492 if (vp->v_iflag & VI_DOOMED) 493 return -1; 494 495 bsize = vp->v_mount->mnt_stat.f_iosize; 496 vblock = address / bsize; 497 voffset = address % bsize; 498 499 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 500 if (err == 0) { 501 if (*rtaddress != -1) 502 *rtaddress += voffset / DEV_BSIZE; 503 if (run) { 504 *run += 1; 505 *run *= bsize/PAGE_SIZE; 506 *run -= voffset/PAGE_SIZE; 507 } 508 } 509 510 return (err); 511 } 512 513 /* 514 * small block filesystem vnode pager input 515 */ 516 static int 517 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m) 518 { 519 struct vnode *vp; 520 struct bufobj *bo; 521 struct buf *bp; 522 struct sf_buf *sf; 523 daddr_t fileaddr; 524 vm_offset_t bsize; 525 vm_page_bits_t bits; 526 int error, i; 527 528 error = 0; 529 vp = object->handle; 530 if (vp->v_iflag & VI_DOOMED) 531 return VM_PAGER_BAD; 532 533 bsize = vp->v_mount->mnt_stat.f_iosize; 534 535 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 536 537 sf = sf_buf_alloc(m, 0); 538 539 for (i = 0; i < PAGE_SIZE / bsize; i++) { 540 vm_ooffset_t address; 541 542 bits = vm_page_bits(i * bsize, bsize); 543 if (m->valid & bits) 544 continue; 545 546 address = IDX_TO_OFF(m->pindex) + i * bsize; 547 if (address >= object->un_pager.vnp.vnp_size) { 548 fileaddr = -1; 549 } else { 550 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 551 if (error) 552 break; 553 } 554 if (fileaddr != -1) { 555 bp = getpbuf(&vnode_pbuf_freecnt); 556 557 /* build a minimal buffer header */ 558 bp->b_iocmd = BIO_READ; 559 bp->b_iodone = bdone; 560 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 561 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 562 bp->b_rcred = crhold(curthread->td_ucred); 563 bp->b_wcred = crhold(curthread->td_ucred); 564 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 565 bp->b_blkno = fileaddr; 566 pbgetbo(bo, bp); 567 bp->b_vp = vp; 568 bp->b_bcount = bsize; 569 bp->b_bufsize = bsize; 570 bp->b_runningbufspace = bp->b_bufsize; 571 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 572 573 /* do the input */ 574 bp->b_iooffset = dbtob(bp->b_blkno); 575 bstrategy(bp); 576 577 bwait(bp, PVM, "vnsrd"); 578 579 if ((bp->b_ioflags & BIO_ERROR) != 0) 580 error = EIO; 581 582 /* 583 * free the buffer header back to the swap buffer pool 584 */ 585 bp->b_vp = NULL; 586 pbrelbo(bp); 587 relpbuf(bp, &vnode_pbuf_freecnt); 588 if (error) 589 break; 590 } else 591 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 592 KASSERT((m->dirty & bits) == 0, 593 ("vnode_pager_input_smlfs: page %p is dirty", m)); 594 VM_OBJECT_WLOCK(object); 595 m->valid |= bits; 596 VM_OBJECT_WUNLOCK(object); 597 } 598 sf_buf_free(sf); 599 if (error) { 600 return VM_PAGER_ERROR; 601 } 602 return VM_PAGER_OK; 603 } 604 605 /* 606 * old style vnode pager input routine 607 */ 608 static int 609 vnode_pager_input_old(vm_object_t object, vm_page_t m) 610 { 611 struct uio auio; 612 struct iovec aiov; 613 int error; 614 int size; 615 struct sf_buf *sf; 616 struct vnode *vp; 617 618 VM_OBJECT_ASSERT_WLOCKED(object); 619 error = 0; 620 621 /* 622 * Return failure if beyond current EOF 623 */ 624 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 625 return VM_PAGER_BAD; 626 } else { 627 size = PAGE_SIZE; 628 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 629 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 630 vp = object->handle; 631 VM_OBJECT_WUNLOCK(object); 632 633 /* 634 * Allocate a kernel virtual address and initialize so that 635 * we can use VOP_READ/WRITE routines. 636 */ 637 sf = sf_buf_alloc(m, 0); 638 639 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 640 aiov.iov_len = size; 641 auio.uio_iov = &aiov; 642 auio.uio_iovcnt = 1; 643 auio.uio_offset = IDX_TO_OFF(m->pindex); 644 auio.uio_segflg = UIO_SYSSPACE; 645 auio.uio_rw = UIO_READ; 646 auio.uio_resid = size; 647 auio.uio_td = curthread; 648 649 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 650 if (!error) { 651 int count = size - auio.uio_resid; 652 653 if (count == 0) 654 error = EINVAL; 655 else if (count != PAGE_SIZE) 656 bzero((caddr_t)sf_buf_kva(sf) + count, 657 PAGE_SIZE - count); 658 } 659 sf_buf_free(sf); 660 661 VM_OBJECT_WLOCK(object); 662 } 663 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 664 if (!error) 665 m->valid = VM_PAGE_BITS_ALL; 666 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 667 } 668 669 /* 670 * generic vnode pager input routine 671 */ 672 673 /* 674 * Local media VFS's that do not implement their own VOP_GETPAGES 675 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 676 * to implement the previous behaviour. 677 * 678 * All other FS's should use the bypass to get to the local media 679 * backing vp's VOP_GETPAGES. 680 */ 681 static int 682 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 683 int *rahead) 684 { 685 struct vnode *vp; 686 int rtval; 687 688 vp = object->handle; 689 VM_OBJECT_WUNLOCK(object); 690 rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead); 691 KASSERT(rtval != EOPNOTSUPP, 692 ("vnode_pager: FS getpages not implemented\n")); 693 VM_OBJECT_WLOCK(object); 694 return rtval; 695 } 696 697 static int 698 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count, 699 int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg) 700 { 701 struct vnode *vp; 702 int rtval; 703 704 vp = object->handle; 705 VM_OBJECT_WUNLOCK(object); 706 rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg); 707 KASSERT(rtval != EOPNOTSUPP, 708 ("vnode_pager: FS getpages_async not implemented\n")); 709 VM_OBJECT_WLOCK(object); 710 return (rtval); 711 } 712 713 /* 714 * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for 715 * local filesystems, where partially valid pages can only occur at 716 * the end of file. 717 */ 718 int 719 vnode_pager_local_getpages(struct vop_getpages_args *ap) 720 { 721 722 return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, 723 ap->a_rbehind, ap->a_rahead, NULL, NULL)); 724 } 725 726 int 727 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap) 728 { 729 730 return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, 731 ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg)); 732 } 733 734 /* 735 * This is now called from local media FS's to operate against their 736 * own vnodes if they fail to implement VOP_GETPAGES. 737 */ 738 int 739 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count, 740 int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg) 741 { 742 vm_object_t object; 743 struct bufobj *bo; 744 struct buf *bp; 745 off_t foff; 746 int bsize, pagesperblock, *freecnt; 747 int error, before, after, rbehind, rahead, poff, i; 748 int bytecount, secmask; 749 750 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 751 ("%s does not support devices", __func__)); 752 753 if (vp->v_iflag & VI_DOOMED) 754 return (VM_PAGER_BAD); 755 756 object = vp->v_object; 757 foff = IDX_TO_OFF(m[0]->pindex); 758 bsize = vp->v_mount->mnt_stat.f_iosize; 759 pagesperblock = bsize / PAGE_SIZE; 760 761 KASSERT(foff < object->un_pager.vnp.vnp_size, 762 ("%s: page %p offset beyond vp %p size", __func__, m[0], vp)); 763 KASSERT(count <= sizeof(bp->b_pages), 764 ("%s: requested %d pages", __func__, count)); 765 766 /* 767 * The last page has valid blocks. Invalid part can only 768 * exist at the end of file, and the page is made fully valid 769 * by zeroing in vm_pager_get_pages(). 770 */ 771 if (m[count - 1]->valid != 0 && --count == 0) { 772 if (iodone != NULL) 773 iodone(arg, m, 1, 0); 774 return (VM_PAGER_OK); 775 } 776 777 /* 778 * Synchronous and asynchronous paging operations use different 779 * free pbuf counters. This is done to avoid asynchronous requests 780 * to consume all pbufs. 781 * Allocate the pbuf at the very beginning of the function, so that 782 * if we are low on certain kind of pbufs don't even proceed to BMAP, 783 * but sleep. 784 */ 785 freecnt = iodone != NULL ? 786 &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt; 787 bp = getpbuf(freecnt); 788 789 /* 790 * Get the underlying device blocks for the file with VOP_BMAP(). 791 * If the file system doesn't support VOP_BMAP, use old way of 792 * getting pages via VOP_READ. 793 */ 794 error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before); 795 if (error == EOPNOTSUPP) { 796 relpbuf(bp, freecnt); 797 VM_OBJECT_WLOCK(object); 798 for (i = 0; i < count; i++) { 799 PCPU_INC(cnt.v_vnodein); 800 PCPU_INC(cnt.v_vnodepgsin); 801 error = vnode_pager_input_old(object, m[i]); 802 if (error) 803 break; 804 } 805 VM_OBJECT_WUNLOCK(object); 806 return (error); 807 } else if (error != 0) { 808 relpbuf(bp, freecnt); 809 return (VM_PAGER_ERROR); 810 } 811 812 /* 813 * If the file system supports BMAP, but blocksize is smaller 814 * than a page size, then use special small filesystem code. 815 */ 816 if (pagesperblock == 0) { 817 relpbuf(bp, freecnt); 818 for (i = 0; i < count; i++) { 819 PCPU_INC(cnt.v_vnodein); 820 PCPU_INC(cnt.v_vnodepgsin); 821 error = vnode_pager_input_smlfs(object, m[i]); 822 if (error) 823 break; 824 } 825 return (error); 826 } 827 828 /* 829 * A sparse file can be encountered only for a single page request, 830 * which may not be preceded by call to vm_pager_haspage(). 831 */ 832 if (bp->b_blkno == -1) { 833 KASSERT(count == 1, 834 ("%s: array[%d] request to a sparse file %p", __func__, 835 count, vp)); 836 relpbuf(bp, freecnt); 837 pmap_zero_page(m[0]); 838 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty", 839 __func__, m[0])); 840 VM_OBJECT_WLOCK(object); 841 m[0]->valid = VM_PAGE_BITS_ALL; 842 VM_OBJECT_WUNLOCK(object); 843 return (VM_PAGER_OK); 844 } 845 846 bp->b_blkno += (foff % bsize) / DEV_BSIZE; 847 848 /* Recalculate blocks available after/before to pages. */ 849 poff = (foff % bsize) / PAGE_SIZE; 850 before *= pagesperblock; 851 before += poff; 852 after *= pagesperblock; 853 after += pagesperblock - (poff + 1); 854 if (m[0]->pindex + after >= object->size) 855 after = object->size - 1 - m[0]->pindex; 856 KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d", 857 __func__, count, after + 1)); 858 after -= count - 1; 859 860 /* Trim requested rbehind/rahead to possible values. */ 861 rbehind = a_rbehind ? *a_rbehind : 0; 862 rahead = a_rahead ? *a_rahead : 0; 863 rbehind = min(rbehind, before); 864 rbehind = min(rbehind, m[0]->pindex); 865 rahead = min(rahead, after); 866 rahead = min(rahead, object->size - m[count - 1]->pindex); 867 KASSERT(rbehind + rahead + count <= sizeof(bp->b_pages), 868 ("%s: behind %d ahead %d count %d", __func__, 869 rbehind, rahead, count)); 870 871 /* 872 * Fill in the bp->b_pages[] array with requested and optional 873 * read behind or read ahead pages. Read behind pages are looked 874 * up in a backward direction, down to a first cached page. Same 875 * for read ahead pages, but there is no need to shift the array 876 * in case of encountering a cached page. 877 */ 878 i = bp->b_npages = 0; 879 if (rbehind) { 880 vm_pindex_t startpindex, tpindex; 881 vm_page_t p; 882 883 VM_OBJECT_WLOCK(object); 884 startpindex = m[0]->pindex - rbehind; 885 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL && 886 p->pindex >= startpindex) 887 startpindex = p->pindex + 1; 888 889 /* tpindex is unsigned; beware of numeric underflow. */ 890 for (tpindex = m[0]->pindex - 1; 891 tpindex >= startpindex && tpindex < m[0]->pindex; 892 tpindex--, i++) { 893 p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL); 894 if (p == NULL) { 895 /* Shift the array. */ 896 for (int j = 0; j < i; j++) 897 bp->b_pages[j] = bp->b_pages[j + 898 tpindex + 1 - startpindex]; 899 break; 900 } 901 bp->b_pages[tpindex - startpindex] = p; 902 } 903 904 bp->b_pgbefore = i; 905 bp->b_npages += i; 906 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE; 907 } else 908 bp->b_pgbefore = 0; 909 910 /* Requested pages. */ 911 for (int j = 0; j < count; j++, i++) 912 bp->b_pages[i] = m[j]; 913 bp->b_npages += count; 914 915 if (rahead) { 916 vm_pindex_t endpindex, tpindex; 917 vm_page_t p; 918 919 if (!VM_OBJECT_WOWNED(object)) 920 VM_OBJECT_WLOCK(object); 921 endpindex = m[count - 1]->pindex + rahead + 1; 922 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL && 923 p->pindex < endpindex) 924 endpindex = p->pindex; 925 if (endpindex > object->size) 926 endpindex = object->size; 927 928 for (tpindex = m[count - 1]->pindex + 1; 929 tpindex < endpindex; i++, tpindex++) { 930 p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL); 931 if (p == NULL) 932 break; 933 bp->b_pages[i] = p; 934 } 935 936 bp->b_pgafter = i - bp->b_npages; 937 bp->b_npages = i; 938 } else 939 bp->b_pgafter = 0; 940 941 if (VM_OBJECT_WOWNED(object)) 942 VM_OBJECT_WUNLOCK(object); 943 944 /* Report back actual behind/ahead read. */ 945 if (a_rbehind) 946 *a_rbehind = bp->b_pgbefore; 947 if (a_rahead) 948 *a_rahead = bp->b_pgafter; 949 950 KASSERT(bp->b_npages <= sizeof(bp->b_pages), 951 ("%s: buf %p overflowed", __func__, bp)); 952 953 /* 954 * Recalculate first offset and bytecount with regards to read behind. 955 * Truncate bytecount to vnode real size and round up physical size 956 * for real devices. 957 */ 958 foff = IDX_TO_OFF(bp->b_pages[0]->pindex); 959 bytecount = bp->b_npages << PAGE_SHIFT; 960 if ((foff + bytecount) > object->un_pager.vnp.vnp_size) 961 bytecount = object->un_pager.vnp.vnp_size - foff; 962 secmask = bo->bo_bsize - 1; 963 KASSERT(secmask < PAGE_SIZE && secmask > 0, 964 ("%s: sector size %d too large", __func__, secmask + 1)); 965 bytecount = (bytecount + secmask) & ~secmask; 966 967 /* 968 * And map the pages to be read into the kva, if the filesystem 969 * requires mapped buffers. 970 */ 971 if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 972 unmapped_buf_allowed) { 973 bp->b_data = unmapped_buf; 974 bp->b_offset = 0; 975 } else { 976 bp->b_data = bp->b_kvabase; 977 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 978 } 979 980 /* Build a minimal buffer header. */ 981 bp->b_iocmd = BIO_READ; 982 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 983 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 984 bp->b_rcred = crhold(curthread->td_ucred); 985 bp->b_wcred = crhold(curthread->td_ucred); 986 pbgetbo(bo, bp); 987 bp->b_vp = vp; 988 bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount; 989 bp->b_iooffset = dbtob(bp->b_blkno); 990 991 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 992 PCPU_INC(cnt.v_vnodein); 993 PCPU_ADD(cnt.v_vnodepgsin, bp->b_npages); 994 995 if (iodone != NULL) { /* async */ 996 bp->b_pgiodone = iodone; 997 bp->b_caller1 = arg; 998 bp->b_iodone = vnode_pager_generic_getpages_done_async; 999 bp->b_flags |= B_ASYNC; 1000 BUF_KERNPROC(bp); 1001 bstrategy(bp); 1002 return (VM_PAGER_OK); 1003 } else { 1004 bp->b_iodone = bdone; 1005 bstrategy(bp); 1006 bwait(bp, PVM, "vnread"); 1007 error = vnode_pager_generic_getpages_done(bp); 1008 for (i = 0; i < bp->b_npages; i++) 1009 bp->b_pages[i] = NULL; 1010 bp->b_vp = NULL; 1011 pbrelbo(bp); 1012 relpbuf(bp, &vnode_pbuf_freecnt); 1013 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 1014 } 1015 } 1016 1017 static void 1018 vnode_pager_generic_getpages_done_async(struct buf *bp) 1019 { 1020 int error; 1021 1022 error = vnode_pager_generic_getpages_done(bp); 1023 /* Run the iodone upon the requested range. */ 1024 bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore, 1025 bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error); 1026 for (int i = 0; i < bp->b_npages; i++) 1027 bp->b_pages[i] = NULL; 1028 bp->b_vp = NULL; 1029 pbrelbo(bp); 1030 relpbuf(bp, &vnode_async_pbuf_freecnt); 1031 } 1032 1033 static int 1034 vnode_pager_generic_getpages_done(struct buf *bp) 1035 { 1036 vm_object_t object; 1037 off_t tfoff, nextoff; 1038 int i, error; 1039 1040 error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0; 1041 object = bp->b_vp->v_object; 1042 1043 if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) { 1044 if (!buf_mapped(bp)) { 1045 bp->b_data = bp->b_kvabase; 1046 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, 1047 bp->b_npages); 1048 } 1049 bzero(bp->b_data + bp->b_bcount, 1050 PAGE_SIZE * bp->b_npages - bp->b_bcount); 1051 } 1052 if (buf_mapped(bp)) { 1053 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages); 1054 bp->b_data = unmapped_buf; 1055 } 1056 1057 VM_OBJECT_WLOCK(object); 1058 for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex); 1059 i < bp->b_npages; i++, tfoff = nextoff) { 1060 vm_page_t mt; 1061 1062 nextoff = tfoff + PAGE_SIZE; 1063 mt = bp->b_pages[i]; 1064 1065 if (nextoff <= object->un_pager.vnp.vnp_size) { 1066 /* 1067 * Read filled up entire page. 1068 */ 1069 mt->valid = VM_PAGE_BITS_ALL; 1070 KASSERT(mt->dirty == 0, 1071 ("%s: page %p is dirty", __func__, mt)); 1072 KASSERT(!pmap_page_is_mapped(mt), 1073 ("%s: page %p is mapped", __func__, mt)); 1074 } else { 1075 /* 1076 * Read did not fill up entire page. 1077 * 1078 * Currently we do not set the entire page valid, 1079 * we just try to clear the piece that we couldn't 1080 * read. 1081 */ 1082 vm_page_set_valid_range(mt, 0, 1083 object->un_pager.vnp.vnp_size - tfoff); 1084 KASSERT((mt->dirty & vm_page_bits(0, 1085 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1086 ("%s: page %p is dirty", __func__, mt)); 1087 } 1088 1089 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter) 1090 vm_page_readahead_finish(mt); 1091 } 1092 VM_OBJECT_WUNLOCK(object); 1093 if (error != 0) 1094 printf("%s: I/O read error %d\n", __func__, error); 1095 1096 return (error); 1097 } 1098 1099 /* 1100 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1101 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1102 * vnode_pager_generic_putpages() to implement the previous behaviour. 1103 * 1104 * All other FS's should use the bypass to get to the local media 1105 * backing vp's VOP_PUTPAGES. 1106 */ 1107 static void 1108 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 1109 int flags, int *rtvals) 1110 { 1111 int rtval; 1112 struct vnode *vp; 1113 int bytes = count * PAGE_SIZE; 1114 1115 /* 1116 * Force synchronous operation if we are extremely low on memory 1117 * to prevent a low-memory deadlock. VOP operations often need to 1118 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1119 * operation ). The swapper handles the case by limiting the amount 1120 * of asynchronous I/O, but that sort of solution doesn't scale well 1121 * for the vnode pager without a lot of work. 1122 * 1123 * Also, the backing vnode's iodone routine may not wake the pageout 1124 * daemon up. This should be probably be addressed XXX. 1125 */ 1126 1127 if (vm_cnt.v_free_count < vm_cnt.v_pageout_free_min) 1128 flags |= VM_PAGER_PUT_SYNC; 1129 1130 /* 1131 * Call device-specific putpages function 1132 */ 1133 vp = object->handle; 1134 VM_OBJECT_WUNLOCK(object); 1135 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals); 1136 KASSERT(rtval != EOPNOTSUPP, 1137 ("vnode_pager: stale FS putpages\n")); 1138 VM_OBJECT_WLOCK(object); 1139 } 1140 1141 1142 /* 1143 * This is now called from local media FS's to operate against their 1144 * own vnodes if they fail to implement VOP_PUTPAGES. 1145 * 1146 * This is typically called indirectly via the pageout daemon and 1147 * clustering has already typically occurred, so in general we ask the 1148 * underlying filesystem to write the data out asynchronously rather 1149 * then delayed. 1150 */ 1151 int 1152 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1153 int flags, int *rtvals) 1154 { 1155 vm_object_t object; 1156 vm_page_t m; 1157 vm_ooffset_t poffset; 1158 struct uio auio; 1159 struct iovec aiov; 1160 int count, error, i, maxsize, ncount, pgoff, ppscheck; 1161 static struct timeval lastfail; 1162 static int curfail; 1163 1164 object = vp->v_object; 1165 count = bytecount / PAGE_SIZE; 1166 1167 for (i = 0; i < count; i++) 1168 rtvals[i] = VM_PAGER_ERROR; 1169 1170 if ((int64_t)ma[0]->pindex < 0) { 1171 printf("vnode_pager_generic_putpages: " 1172 "attempt to write meta-data 0x%jx(%lx)\n", 1173 (uintmax_t)ma[0]->pindex, (u_long)ma[0]->dirty); 1174 rtvals[0] = VM_PAGER_BAD; 1175 return (VM_PAGER_BAD); 1176 } 1177 1178 maxsize = count * PAGE_SIZE; 1179 ncount = count; 1180 1181 poffset = IDX_TO_OFF(ma[0]->pindex); 1182 1183 /* 1184 * If the page-aligned write is larger then the actual file we 1185 * have to invalidate pages occurring beyond the file EOF. However, 1186 * there is an edge case where a file may not be page-aligned where 1187 * the last page is partially invalid. In this case the filesystem 1188 * may not properly clear the dirty bits for the entire page (which 1189 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1190 * With the page locked we are free to fix-up the dirty bits here. 1191 * 1192 * We do not under any circumstances truncate the valid bits, as 1193 * this will screw up bogus page replacement. 1194 */ 1195 VM_OBJECT_WLOCK(object); 1196 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1197 if (object->un_pager.vnp.vnp_size > poffset) { 1198 maxsize = object->un_pager.vnp.vnp_size - poffset; 1199 ncount = btoc(maxsize); 1200 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1201 /* 1202 * If the object is locked and the following 1203 * conditions hold, then the page's dirty 1204 * field cannot be concurrently changed by a 1205 * pmap operation. 1206 */ 1207 m = ma[ncount - 1]; 1208 vm_page_assert_sbusied(m); 1209 KASSERT(!pmap_page_is_write_mapped(m), 1210 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1211 MPASS(m->dirty != 0); 1212 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1213 pgoff); 1214 } 1215 } else { 1216 maxsize = 0; 1217 ncount = 0; 1218 } 1219 for (i = ncount; i < count; i++) 1220 rtvals[i] = VM_PAGER_BAD; 1221 } 1222 for (i = 0; i < ncount - ((btoc(maxsize) & PAGE_MASK) != 0); i++) 1223 MPASS(ma[i]->dirty == VM_PAGE_BITS_ALL); 1224 VM_OBJECT_WUNLOCK(object); 1225 1226 aiov.iov_base = NULL; 1227 aiov.iov_len = maxsize; 1228 auio.uio_iov = &aiov; 1229 auio.uio_iovcnt = 1; 1230 auio.uio_offset = poffset; 1231 auio.uio_segflg = UIO_NOCOPY; 1232 auio.uio_rw = UIO_WRITE; 1233 auio.uio_resid = maxsize; 1234 auio.uio_td = NULL; 1235 error = VOP_WRITE(vp, &auio, vnode_pager_putpages_ioflags(flags), 1236 curthread->td_ucred); 1237 PCPU_INC(cnt.v_vnodeout); 1238 PCPU_ADD(cnt.v_vnodepgsout, ncount); 1239 1240 ppscheck = 0; 1241 if (error != 0 && (ppscheck = ppsratecheck(&lastfail, &curfail, 1)) 1242 != 0) 1243 printf("vnode_pager_putpages: I/O error %d\n", error); 1244 if (auio.uio_resid != 0 && (ppscheck != 0 || 1245 ppsratecheck(&lastfail, &curfail, 1) != 0)) 1246 printf("vnode_pager_putpages: residual I/O %zd at %ju\n", 1247 auio.uio_resid, (uintmax_t)ma[0]->pindex); 1248 for (i = 0; i < ncount; i++) 1249 rtvals[i] = VM_PAGER_OK; 1250 return (rtvals[0]); 1251 } 1252 1253 int 1254 vnode_pager_putpages_ioflags(int pager_flags) 1255 { 1256 int ioflags; 1257 1258 /* 1259 * Pageouts are already clustered, use IO_ASYNC to force a 1260 * bawrite() rather then a bdwrite() to prevent paging I/O 1261 * from saturating the buffer cache. Dummy-up the sequential 1262 * heuristic to cause large ranges to cluster. If neither 1263 * IO_SYNC or IO_ASYNC is set, the system decides how to 1264 * cluster. 1265 */ 1266 ioflags = IO_VMIO; 1267 if ((pager_flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) != 0) 1268 ioflags |= IO_SYNC; 1269 else if ((pager_flags & VM_PAGER_CLUSTER_OK) == 0) 1270 ioflags |= IO_ASYNC; 1271 ioflags |= (pager_flags & VM_PAGER_PUT_INVAL) != 0 ? IO_INVAL: 0; 1272 #ifdef notyet 1273 ioflags |= (pager_flags & VM_PAGER_PUT_NOREUSE) != 0 ? IO_NOREUSE : 0; 1274 #endif 1275 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1276 return (ioflags); 1277 } 1278 1279 void 1280 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written) 1281 { 1282 vm_object_t obj; 1283 int i, pos; 1284 1285 if (written == 0) 1286 return; 1287 obj = ma[0]->object; 1288 VM_OBJECT_WLOCK(obj); 1289 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1290 if (pos < trunc_page(written)) { 1291 rtvals[i] = VM_PAGER_OK; 1292 vm_page_undirty(ma[i]); 1293 } else { 1294 /* Partially written page. */ 1295 rtvals[i] = VM_PAGER_AGAIN; 1296 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1297 } 1298 } 1299 VM_OBJECT_WUNLOCK(obj); 1300 } 1301 1302 void 1303 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1304 vm_offset_t end) 1305 { 1306 struct vnode *vp; 1307 vm_ooffset_t old_wm; 1308 1309 VM_OBJECT_WLOCK(object); 1310 if (object->type != OBJT_VNODE) { 1311 VM_OBJECT_WUNLOCK(object); 1312 return; 1313 } 1314 old_wm = object->un_pager.vnp.writemappings; 1315 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1316 vp = object->handle; 1317 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1318 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1319 VOP_ADD_WRITECOUNT(vp, 1); 1320 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1321 __func__, vp, vp->v_writecount); 1322 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1323 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1324 VOP_ADD_WRITECOUNT(vp, -1); 1325 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1326 __func__, vp, vp->v_writecount); 1327 } 1328 VM_OBJECT_WUNLOCK(object); 1329 } 1330 1331 void 1332 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1333 vm_offset_t end) 1334 { 1335 struct vnode *vp; 1336 struct mount *mp; 1337 vm_offset_t inc; 1338 1339 VM_OBJECT_WLOCK(object); 1340 1341 /* 1342 * First, recheck the object type to account for the race when 1343 * the vnode is reclaimed. 1344 */ 1345 if (object->type != OBJT_VNODE) { 1346 VM_OBJECT_WUNLOCK(object); 1347 return; 1348 } 1349 1350 /* 1351 * Optimize for the case when writemappings is not going to 1352 * zero. 1353 */ 1354 inc = end - start; 1355 if (object->un_pager.vnp.writemappings != inc) { 1356 object->un_pager.vnp.writemappings -= inc; 1357 VM_OBJECT_WUNLOCK(object); 1358 return; 1359 } 1360 1361 vp = object->handle; 1362 vhold(vp); 1363 VM_OBJECT_WUNLOCK(object); 1364 mp = NULL; 1365 vn_start_write(vp, &mp, V_WAIT); 1366 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1367 1368 /* 1369 * Decrement the object's writemappings, by swapping the start 1370 * and end arguments for vnode_pager_update_writecount(). If 1371 * there was not a race with vnode reclaimation, then the 1372 * vnode's v_writecount is decremented. 1373 */ 1374 vnode_pager_update_writecount(object, end, start); 1375 VOP_UNLOCK(vp, 0); 1376 vdrop(vp); 1377 if (mp != NULL) 1378 vn_finished_write(mp); 1379 }
Cache object: d8eb7204593f6dcfcd7a725f51bd444a
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