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sys/vm/vnode_pager.c
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1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1990 University of Utah. 5 * Copyright (c) 1991 The Regents of the University of California. 6 * All rights reserved. 7 * Copyright (c) 1993, 1994 John S. Dyson 8 * Copyright (c) 1995, David Greenman 9 * 10 * This code is derived from software contributed to Berkeley by 11 * the Systems Programming Group of the University of Utah Computer 12 * Science Department. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 43 */ 44 45 /* 46 * Page to/from files (vnodes). 47 */ 48 49 /* 50 * TODO: 51 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 52 * greatly re-simplify the vnode_pager. 53 */ 54 55 #include <sys/cdefs.h> 56 __FBSDID("$FreeBSD: releng/12.0/sys/vm/vnode_pager.c 331723 2018-03-29 02:54:50Z jeff $"); 57 58 #include "opt_vm.h" 59 60 #include <sys/param.h> 61 #include <sys/systm.h> 62 #include <sys/sysctl.h> 63 #include <sys/proc.h> 64 #include <sys/vnode.h> 65 #include <sys/mount.h> 66 #include <sys/bio.h> 67 #include <sys/buf.h> 68 #include <sys/vmmeter.h> 69 #include <sys/limits.h> 70 #include <sys/conf.h> 71 #include <sys/rwlock.h> 72 #include <sys/sf_buf.h> 73 #include <sys/domainset.h> 74 75 #include <machine/atomic.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <vm/vm_object.h> 80 #include <vm/vm_page.h> 81 #include <vm/vm_pager.h> 82 #include <vm/vm_map.h> 83 #include <vm/vnode_pager.h> 84 #include <vm/vm_extern.h> 85 86 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, 87 daddr_t *rtaddress, int *run); 88 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); 89 static int vnode_pager_input_old(vm_object_t object, vm_page_t m); 90 static void vnode_pager_dealloc(vm_object_t); 91 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); 92 static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *, 93 int *, vop_getpages_iodone_t, void *); 94 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); 95 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); 96 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 97 vm_ooffset_t, struct ucred *cred); 98 static int vnode_pager_generic_getpages_done(struct buf *); 99 static void vnode_pager_generic_getpages_done_async(struct buf *); 100 101 struct pagerops vnodepagerops = { 102 .pgo_alloc = vnode_pager_alloc, 103 .pgo_dealloc = vnode_pager_dealloc, 104 .pgo_getpages = vnode_pager_getpages, 105 .pgo_getpages_async = vnode_pager_getpages_async, 106 .pgo_putpages = vnode_pager_putpages, 107 .pgo_haspage = vnode_pager_haspage, 108 }; 109 110 int vnode_pbuf_freecnt; 111 int vnode_async_pbuf_freecnt; 112 113 static struct domainset *vnode_domainset = NULL; 114 115 SYSCTL_PROC(_debug, OID_AUTO, vnode_domainset, CTLTYPE_STRING | CTLFLAG_RW, 116 &vnode_domainset, 0, sysctl_handle_domainset, "A", 117 "Default vnode NUMA policy"); 118 119 /* Create the VM system backing object for this vnode */ 120 int 121 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td) 122 { 123 vm_object_t object; 124 vm_ooffset_t size = isize; 125 struct vattr va; 126 127 if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE) 128 return (0); 129 130 while ((object = vp->v_object) != NULL) { 131 VM_OBJECT_WLOCK(object); 132 if (!(object->flags & OBJ_DEAD)) { 133 VM_OBJECT_WUNLOCK(object); 134 return (0); 135 } 136 VOP_UNLOCK(vp, 0); 137 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 138 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0); 139 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 140 } 141 142 if (size == 0) { 143 if (vn_isdisk(vp, NULL)) { 144 size = IDX_TO_OFF(INT_MAX); 145 } else { 146 if (VOP_GETATTR(vp, &va, td->td_ucred)) 147 return (0); 148 size = va.va_size; 149 } 150 } 151 152 object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred); 153 /* 154 * Dereference the reference we just created. This assumes 155 * that the object is associated with the vp. 156 */ 157 VM_OBJECT_WLOCK(object); 158 object->ref_count--; 159 VM_OBJECT_WUNLOCK(object); 160 vrele(vp); 161 162 KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object")); 163 164 return (0); 165 } 166 167 void 168 vnode_destroy_vobject(struct vnode *vp) 169 { 170 struct vm_object *obj; 171 172 obj = vp->v_object; 173 if (obj == NULL) 174 return; 175 ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject"); 176 VM_OBJECT_WLOCK(obj); 177 umtx_shm_object_terminated(obj); 178 if (obj->ref_count == 0) { 179 /* 180 * don't double-terminate the object 181 */ 182 if ((obj->flags & OBJ_DEAD) == 0) { 183 vm_object_terminate(obj); 184 } else { 185 /* 186 * Waiters were already handled during object 187 * termination. The exclusive vnode lock hopefully 188 * prevented new waiters from referencing the dying 189 * object. 190 */ 191 KASSERT((obj->flags & OBJ_DISCONNECTWNT) == 0, 192 ("OBJ_DISCONNECTWNT set obj %p flags %x", 193 obj, obj->flags)); 194 vp->v_object = NULL; 195 VM_OBJECT_WUNLOCK(obj); 196 } 197 } else { 198 /* 199 * Woe to the process that tries to page now :-). 200 */ 201 vm_pager_deallocate(obj); 202 VM_OBJECT_WUNLOCK(obj); 203 } 204 KASSERT(vp->v_object == NULL, ("vp %p obj %p", vp, vp->v_object)); 205 } 206 207 208 /* 209 * Allocate (or lookup) pager for a vnode. 210 * Handle is a vnode pointer. 211 * 212 * MPSAFE 213 */ 214 vm_object_t 215 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 216 vm_ooffset_t offset, struct ucred *cred) 217 { 218 vm_object_t object; 219 struct vnode *vp; 220 221 /* 222 * Pageout to vnode, no can do yet. 223 */ 224 if (handle == NULL) 225 return (NULL); 226 227 vp = (struct vnode *) handle; 228 229 /* 230 * If the object is being terminated, wait for it to 231 * go away. 232 */ 233 retry: 234 while ((object = vp->v_object) != NULL) { 235 VM_OBJECT_WLOCK(object); 236 if ((object->flags & OBJ_DEAD) == 0) 237 break; 238 vm_object_set_flag(object, OBJ_DISCONNECTWNT); 239 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0); 240 } 241 242 KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference")); 243 244 if (object == NULL) { 245 /* 246 * Add an object of the appropriate size 247 */ 248 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 249 250 object->un_pager.vnp.vnp_size = size; 251 object->un_pager.vnp.writemappings = 0; 252 object->domain.dr_policy = vnode_domainset; 253 254 object->handle = handle; 255 VI_LOCK(vp); 256 if (vp->v_object != NULL) { 257 /* 258 * Object has been created while we were sleeping 259 */ 260 VI_UNLOCK(vp); 261 VM_OBJECT_WLOCK(object); 262 KASSERT(object->ref_count == 1, 263 ("leaked ref %p %d", object, object->ref_count)); 264 object->type = OBJT_DEAD; 265 object->ref_count = 0; 266 VM_OBJECT_WUNLOCK(object); 267 vm_object_destroy(object); 268 goto retry; 269 } 270 vp->v_object = object; 271 VI_UNLOCK(vp); 272 } else { 273 object->ref_count++; 274 #if VM_NRESERVLEVEL > 0 275 vm_object_color(object, 0); 276 #endif 277 VM_OBJECT_WUNLOCK(object); 278 } 279 vrefact(vp); 280 return (object); 281 } 282 283 /* 284 * The object must be locked. 285 */ 286 static void 287 vnode_pager_dealloc(vm_object_t object) 288 { 289 struct vnode *vp; 290 int refs; 291 292 vp = object->handle; 293 if (vp == NULL) 294 panic("vnode_pager_dealloc: pager already dealloced"); 295 296 VM_OBJECT_ASSERT_WLOCKED(object); 297 vm_object_pip_wait(object, "vnpdea"); 298 refs = object->ref_count; 299 300 object->handle = NULL; 301 object->type = OBJT_DEAD; 302 if (object->flags & OBJ_DISCONNECTWNT) { 303 vm_object_clear_flag(object, OBJ_DISCONNECTWNT); 304 wakeup(object); 305 } 306 ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc"); 307 if (object->un_pager.vnp.writemappings > 0) { 308 object->un_pager.vnp.writemappings = 0; 309 VOP_ADD_WRITECOUNT(vp, -1); 310 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 311 __func__, vp, vp->v_writecount); 312 } 313 vp->v_object = NULL; 314 VOP_UNSET_TEXT(vp); 315 VM_OBJECT_WUNLOCK(object); 316 while (refs-- > 0) 317 vunref(vp); 318 VM_OBJECT_WLOCK(object); 319 } 320 321 static boolean_t 322 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 323 int *after) 324 { 325 struct vnode *vp = object->handle; 326 daddr_t bn; 327 int err; 328 daddr_t reqblock; 329 int poff; 330 int bsize; 331 int pagesperblock, blocksperpage; 332 333 VM_OBJECT_ASSERT_WLOCKED(object); 334 /* 335 * If no vp or vp is doomed or marked transparent to VM, we do not 336 * have the page. 337 */ 338 if (vp == NULL || vp->v_iflag & VI_DOOMED) 339 return FALSE; 340 /* 341 * If the offset is beyond end of file we do 342 * not have the page. 343 */ 344 if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size) 345 return FALSE; 346 347 bsize = vp->v_mount->mnt_stat.f_iosize; 348 pagesperblock = bsize / PAGE_SIZE; 349 blocksperpage = 0; 350 if (pagesperblock > 0) { 351 reqblock = pindex / pagesperblock; 352 } else { 353 blocksperpage = (PAGE_SIZE / bsize); 354 reqblock = pindex * blocksperpage; 355 } 356 VM_OBJECT_WUNLOCK(object); 357 err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before); 358 VM_OBJECT_WLOCK(object); 359 if (err) 360 return TRUE; 361 if (bn == -1) 362 return FALSE; 363 if (pagesperblock > 0) { 364 poff = pindex - (reqblock * pagesperblock); 365 if (before) { 366 *before *= pagesperblock; 367 *before += poff; 368 } 369 if (after) { 370 /* 371 * The BMAP vop can report a partial block in the 372 * 'after', but must not report blocks after EOF. 373 * Assert the latter, and truncate 'after' in case 374 * of the former. 375 */ 376 KASSERT((reqblock + *after) * pagesperblock < 377 roundup2(object->size, pagesperblock), 378 ("%s: reqblock %jd after %d size %ju", __func__, 379 (intmax_t )reqblock, *after, 380 (uintmax_t )object->size)); 381 *after *= pagesperblock; 382 *after += pagesperblock - (poff + 1); 383 if (pindex + *after >= object->size) 384 *after = object->size - 1 - pindex; 385 } 386 } else { 387 if (before) { 388 *before /= blocksperpage; 389 } 390 391 if (after) { 392 *after /= blocksperpage; 393 } 394 } 395 return TRUE; 396 } 397 398 /* 399 * Lets the VM system know about a change in size for a file. 400 * We adjust our own internal size and flush any cached pages in 401 * the associated object that are affected by the size change. 402 * 403 * Note: this routine may be invoked as a result of a pager put 404 * operation (possibly at object termination time), so we must be careful. 405 */ 406 void 407 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 408 { 409 vm_object_t object; 410 vm_page_t m; 411 vm_pindex_t nobjsize; 412 413 if ((object = vp->v_object) == NULL) 414 return; 415 /* ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */ 416 VM_OBJECT_WLOCK(object); 417 if (object->type == OBJT_DEAD) { 418 VM_OBJECT_WUNLOCK(object); 419 return; 420 } 421 KASSERT(object->type == OBJT_VNODE, 422 ("not vnode-backed object %p", object)); 423 if (nsize == object->un_pager.vnp.vnp_size) { 424 /* 425 * Hasn't changed size 426 */ 427 VM_OBJECT_WUNLOCK(object); 428 return; 429 } 430 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 431 if (nsize < object->un_pager.vnp.vnp_size) { 432 /* 433 * File has shrunk. Toss any cached pages beyond the new EOF. 434 */ 435 if (nobjsize < object->size) 436 vm_object_page_remove(object, nobjsize, object->size, 437 0); 438 /* 439 * this gets rid of garbage at the end of a page that is now 440 * only partially backed by the vnode. 441 * 442 * XXX for some reason (I don't know yet), if we take a 443 * completely invalid page and mark it partially valid 444 * it can screw up NFS reads, so we don't allow the case. 445 */ 446 if ((nsize & PAGE_MASK) && 447 (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL && 448 m->valid != 0) { 449 int base = (int)nsize & PAGE_MASK; 450 int size = PAGE_SIZE - base; 451 452 /* 453 * Clear out partial-page garbage in case 454 * the page has been mapped. 455 */ 456 pmap_zero_page_area(m, base, size); 457 458 /* 459 * Update the valid bits to reflect the blocks that 460 * have been zeroed. Some of these valid bits may 461 * have already been set. 462 */ 463 vm_page_set_valid_range(m, base, size); 464 465 /* 466 * Round "base" to the next block boundary so that the 467 * dirty bit for a partially zeroed block is not 468 * cleared. 469 */ 470 base = roundup2(base, DEV_BSIZE); 471 472 /* 473 * Clear out partial-page dirty bits. 474 * 475 * note that we do not clear out the valid 476 * bits. This would prevent bogus_page 477 * replacement from working properly. 478 */ 479 vm_page_clear_dirty(m, base, PAGE_SIZE - base); 480 } 481 } 482 object->un_pager.vnp.vnp_size = nsize; 483 object->size = nobjsize; 484 VM_OBJECT_WUNLOCK(object); 485 } 486 487 /* 488 * calculate the linear (byte) disk address of specified virtual 489 * file address 490 */ 491 static int 492 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress, 493 int *run) 494 { 495 int bsize; 496 int err; 497 daddr_t vblock; 498 daddr_t voffset; 499 500 if (address < 0) 501 return -1; 502 503 if (vp->v_iflag & VI_DOOMED) 504 return -1; 505 506 bsize = vp->v_mount->mnt_stat.f_iosize; 507 vblock = address / bsize; 508 voffset = address % bsize; 509 510 err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL); 511 if (err == 0) { 512 if (*rtaddress != -1) 513 *rtaddress += voffset / DEV_BSIZE; 514 if (run) { 515 *run += 1; 516 *run *= bsize/PAGE_SIZE; 517 *run -= voffset/PAGE_SIZE; 518 } 519 } 520 521 return (err); 522 } 523 524 /* 525 * small block filesystem vnode pager input 526 */ 527 static int 528 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m) 529 { 530 struct vnode *vp; 531 struct bufobj *bo; 532 struct buf *bp; 533 struct sf_buf *sf; 534 daddr_t fileaddr; 535 vm_offset_t bsize; 536 vm_page_bits_t bits; 537 int error, i; 538 539 error = 0; 540 vp = object->handle; 541 if (vp->v_iflag & VI_DOOMED) 542 return VM_PAGER_BAD; 543 544 bsize = vp->v_mount->mnt_stat.f_iosize; 545 546 VOP_BMAP(vp, 0, &bo, 0, NULL, NULL); 547 548 sf = sf_buf_alloc(m, 0); 549 550 for (i = 0; i < PAGE_SIZE / bsize; i++) { 551 vm_ooffset_t address; 552 553 bits = vm_page_bits(i * bsize, bsize); 554 if (m->valid & bits) 555 continue; 556 557 address = IDX_TO_OFF(m->pindex) + i * bsize; 558 if (address >= object->un_pager.vnp.vnp_size) { 559 fileaddr = -1; 560 } else { 561 error = vnode_pager_addr(vp, address, &fileaddr, NULL); 562 if (error) 563 break; 564 } 565 if (fileaddr != -1) { 566 bp = getpbuf(&vnode_pbuf_freecnt); 567 568 /* build a minimal buffer header */ 569 bp->b_iocmd = BIO_READ; 570 bp->b_iodone = bdone; 571 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 572 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 573 bp->b_rcred = crhold(curthread->td_ucred); 574 bp->b_wcred = crhold(curthread->td_ucred); 575 bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize; 576 bp->b_blkno = fileaddr; 577 pbgetbo(bo, bp); 578 bp->b_vp = vp; 579 bp->b_bcount = bsize; 580 bp->b_bufsize = bsize; 581 bp->b_runningbufspace = bp->b_bufsize; 582 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 583 584 /* do the input */ 585 bp->b_iooffset = dbtob(bp->b_blkno); 586 bstrategy(bp); 587 588 bwait(bp, PVM, "vnsrd"); 589 590 if ((bp->b_ioflags & BIO_ERROR) != 0) 591 error = EIO; 592 593 /* 594 * free the buffer header back to the swap buffer pool 595 */ 596 bp->b_vp = NULL; 597 pbrelbo(bp); 598 relpbuf(bp, &vnode_pbuf_freecnt); 599 if (error) 600 break; 601 } else 602 bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize); 603 KASSERT((m->dirty & bits) == 0, 604 ("vnode_pager_input_smlfs: page %p is dirty", m)); 605 VM_OBJECT_WLOCK(object); 606 m->valid |= bits; 607 VM_OBJECT_WUNLOCK(object); 608 } 609 sf_buf_free(sf); 610 if (error) { 611 return VM_PAGER_ERROR; 612 } 613 return VM_PAGER_OK; 614 } 615 616 /* 617 * old style vnode pager input routine 618 */ 619 static int 620 vnode_pager_input_old(vm_object_t object, vm_page_t m) 621 { 622 struct uio auio; 623 struct iovec aiov; 624 int error; 625 int size; 626 struct sf_buf *sf; 627 struct vnode *vp; 628 629 VM_OBJECT_ASSERT_WLOCKED(object); 630 error = 0; 631 632 /* 633 * Return failure if beyond current EOF 634 */ 635 if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { 636 return VM_PAGER_BAD; 637 } else { 638 size = PAGE_SIZE; 639 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) 640 size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); 641 vp = object->handle; 642 VM_OBJECT_WUNLOCK(object); 643 644 /* 645 * Allocate a kernel virtual address and initialize so that 646 * we can use VOP_READ/WRITE routines. 647 */ 648 sf = sf_buf_alloc(m, 0); 649 650 aiov.iov_base = (caddr_t)sf_buf_kva(sf); 651 aiov.iov_len = size; 652 auio.uio_iov = &aiov; 653 auio.uio_iovcnt = 1; 654 auio.uio_offset = IDX_TO_OFF(m->pindex); 655 auio.uio_segflg = UIO_SYSSPACE; 656 auio.uio_rw = UIO_READ; 657 auio.uio_resid = size; 658 auio.uio_td = curthread; 659 660 error = VOP_READ(vp, &auio, 0, curthread->td_ucred); 661 if (!error) { 662 int count = size - auio.uio_resid; 663 664 if (count == 0) 665 error = EINVAL; 666 else if (count != PAGE_SIZE) 667 bzero((caddr_t)sf_buf_kva(sf) + count, 668 PAGE_SIZE - count); 669 } 670 sf_buf_free(sf); 671 672 VM_OBJECT_WLOCK(object); 673 } 674 KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m)); 675 if (!error) 676 m->valid = VM_PAGE_BITS_ALL; 677 return error ? VM_PAGER_ERROR : VM_PAGER_OK; 678 } 679 680 /* 681 * generic vnode pager input routine 682 */ 683 684 /* 685 * Local media VFS's that do not implement their own VOP_GETPAGES 686 * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() 687 * to implement the previous behaviour. 688 * 689 * All other FS's should use the bypass to get to the local media 690 * backing vp's VOP_GETPAGES. 691 */ 692 static int 693 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind, 694 int *rahead) 695 { 696 struct vnode *vp; 697 int rtval; 698 699 vp = object->handle; 700 VM_OBJECT_WUNLOCK(object); 701 rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead); 702 KASSERT(rtval != EOPNOTSUPP, 703 ("vnode_pager: FS getpages not implemented\n")); 704 VM_OBJECT_WLOCK(object); 705 return rtval; 706 } 707 708 static int 709 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count, 710 int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg) 711 { 712 struct vnode *vp; 713 int rtval; 714 715 vp = object->handle; 716 VM_OBJECT_WUNLOCK(object); 717 rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg); 718 KASSERT(rtval != EOPNOTSUPP, 719 ("vnode_pager: FS getpages_async not implemented\n")); 720 VM_OBJECT_WLOCK(object); 721 return (rtval); 722 } 723 724 /* 725 * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for 726 * local filesystems, where partially valid pages can only occur at 727 * the end of file. 728 */ 729 int 730 vnode_pager_local_getpages(struct vop_getpages_args *ap) 731 { 732 733 return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, 734 ap->a_rbehind, ap->a_rahead, NULL, NULL)); 735 } 736 737 int 738 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap) 739 { 740 741 return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count, 742 ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg)); 743 } 744 745 /* 746 * This is now called from local media FS's to operate against their 747 * own vnodes if they fail to implement VOP_GETPAGES. 748 */ 749 int 750 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count, 751 int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg) 752 { 753 vm_object_t object; 754 struct bufobj *bo; 755 struct buf *bp; 756 off_t foff; 757 #ifdef INVARIANTS 758 off_t blkno0; 759 #endif 760 int bsize, pagesperblock, *freecnt; 761 int error, before, after, rbehind, rahead, poff, i; 762 int bytecount, secmask; 763 764 KASSERT(vp->v_type != VCHR && vp->v_type != VBLK, 765 ("%s does not support devices", __func__)); 766 767 if (vp->v_iflag & VI_DOOMED) 768 return (VM_PAGER_BAD); 769 770 object = vp->v_object; 771 foff = IDX_TO_OFF(m[0]->pindex); 772 bsize = vp->v_mount->mnt_stat.f_iosize; 773 pagesperblock = bsize / PAGE_SIZE; 774 775 KASSERT(foff < object->un_pager.vnp.vnp_size, 776 ("%s: page %p offset beyond vp %p size", __func__, m[0], vp)); 777 KASSERT(count <= sizeof(bp->b_pages), 778 ("%s: requested %d pages", __func__, count)); 779 780 /* 781 * The last page has valid blocks. Invalid part can only 782 * exist at the end of file, and the page is made fully valid 783 * by zeroing in vm_pager_get_pages(). 784 */ 785 if (m[count - 1]->valid != 0 && --count == 0) { 786 if (iodone != NULL) 787 iodone(arg, m, 1, 0); 788 return (VM_PAGER_OK); 789 } 790 791 /* 792 * Synchronous and asynchronous paging operations use different 793 * free pbuf counters. This is done to avoid asynchronous requests 794 * to consume all pbufs. 795 * Allocate the pbuf at the very beginning of the function, so that 796 * if we are low on certain kind of pbufs don't even proceed to BMAP, 797 * but sleep. 798 */ 799 freecnt = iodone != NULL ? 800 &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt; 801 bp = getpbuf(freecnt); 802 803 /* 804 * Get the underlying device blocks for the file with VOP_BMAP(). 805 * If the file system doesn't support VOP_BMAP, use old way of 806 * getting pages via VOP_READ. 807 */ 808 error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before); 809 if (error == EOPNOTSUPP) { 810 relpbuf(bp, freecnt); 811 VM_OBJECT_WLOCK(object); 812 for (i = 0; i < count; i++) { 813 VM_CNT_INC(v_vnodein); 814 VM_CNT_INC(v_vnodepgsin); 815 error = vnode_pager_input_old(object, m[i]); 816 if (error) 817 break; 818 } 819 VM_OBJECT_WUNLOCK(object); 820 return (error); 821 } else if (error != 0) { 822 relpbuf(bp, freecnt); 823 return (VM_PAGER_ERROR); 824 } 825 826 /* 827 * If the file system supports BMAP, but blocksize is smaller 828 * than a page size, then use special small filesystem code. 829 */ 830 if (pagesperblock == 0) { 831 relpbuf(bp, freecnt); 832 for (i = 0; i < count; i++) { 833 VM_CNT_INC(v_vnodein); 834 VM_CNT_INC(v_vnodepgsin); 835 error = vnode_pager_input_smlfs(object, m[i]); 836 if (error) 837 break; 838 } 839 return (error); 840 } 841 842 /* 843 * A sparse file can be encountered only for a single page request, 844 * which may not be preceded by call to vm_pager_haspage(). 845 */ 846 if (bp->b_blkno == -1) { 847 KASSERT(count == 1, 848 ("%s: array[%d] request to a sparse file %p", __func__, 849 count, vp)); 850 relpbuf(bp, freecnt); 851 pmap_zero_page(m[0]); 852 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty", 853 __func__, m[0])); 854 VM_OBJECT_WLOCK(object); 855 m[0]->valid = VM_PAGE_BITS_ALL; 856 VM_OBJECT_WUNLOCK(object); 857 return (VM_PAGER_OK); 858 } 859 860 #ifdef INVARIANTS 861 blkno0 = bp->b_blkno; 862 #endif 863 bp->b_blkno += (foff % bsize) / DEV_BSIZE; 864 865 /* Recalculate blocks available after/before to pages. */ 866 poff = (foff % bsize) / PAGE_SIZE; 867 before *= pagesperblock; 868 before += poff; 869 after *= pagesperblock; 870 after += pagesperblock - (poff + 1); 871 if (m[0]->pindex + after >= object->size) 872 after = object->size - 1 - m[0]->pindex; 873 KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d", 874 __func__, count, after + 1)); 875 after -= count - 1; 876 877 /* Trim requested rbehind/rahead to possible values. */ 878 rbehind = a_rbehind ? *a_rbehind : 0; 879 rahead = a_rahead ? *a_rahead : 0; 880 rbehind = min(rbehind, before); 881 rbehind = min(rbehind, m[0]->pindex); 882 rahead = min(rahead, after); 883 rahead = min(rahead, object->size - m[count - 1]->pindex); 884 /* 885 * Check that total amount of pages fit into buf. Trim rbehind and 886 * rahead evenly if not. 887 */ 888 if (rbehind + rahead + count > nitems(bp->b_pages)) { 889 int trim, sum; 890 891 trim = rbehind + rahead + count - nitems(bp->b_pages) + 1; 892 sum = rbehind + rahead; 893 if (rbehind == before) { 894 /* Roundup rbehind trim to block size. */ 895 rbehind -= roundup(trim * rbehind / sum, pagesperblock); 896 if (rbehind < 0) 897 rbehind = 0; 898 } else 899 rbehind -= trim * rbehind / sum; 900 rahead -= trim * rahead / sum; 901 } 902 KASSERT(rbehind + rahead + count <= nitems(bp->b_pages), 903 ("%s: behind %d ahead %d count %d", __func__, 904 rbehind, rahead, count)); 905 906 /* 907 * Fill in the bp->b_pages[] array with requested and optional 908 * read behind or read ahead pages. Read behind pages are looked 909 * up in a backward direction, down to a first cached page. Same 910 * for read ahead pages, but there is no need to shift the array 911 * in case of encountering a cached page. 912 */ 913 i = bp->b_npages = 0; 914 if (rbehind) { 915 vm_pindex_t startpindex, tpindex; 916 vm_page_t p; 917 918 VM_OBJECT_WLOCK(object); 919 startpindex = m[0]->pindex - rbehind; 920 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL && 921 p->pindex >= startpindex) 922 startpindex = p->pindex + 1; 923 924 /* tpindex is unsigned; beware of numeric underflow. */ 925 for (tpindex = m[0]->pindex - 1; 926 tpindex >= startpindex && tpindex < m[0]->pindex; 927 tpindex--, i++) { 928 p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL); 929 if (p == NULL) { 930 /* Shift the array. */ 931 for (int j = 0; j < i; j++) 932 bp->b_pages[j] = bp->b_pages[j + 933 tpindex + 1 - startpindex]; 934 break; 935 } 936 bp->b_pages[tpindex - startpindex] = p; 937 } 938 939 bp->b_pgbefore = i; 940 bp->b_npages += i; 941 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE; 942 } else 943 bp->b_pgbefore = 0; 944 945 /* Requested pages. */ 946 for (int j = 0; j < count; j++, i++) 947 bp->b_pages[i] = m[j]; 948 bp->b_npages += count; 949 950 if (rahead) { 951 vm_pindex_t endpindex, tpindex; 952 vm_page_t p; 953 954 if (!VM_OBJECT_WOWNED(object)) 955 VM_OBJECT_WLOCK(object); 956 endpindex = m[count - 1]->pindex + rahead + 1; 957 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL && 958 p->pindex < endpindex) 959 endpindex = p->pindex; 960 if (endpindex > object->size) 961 endpindex = object->size; 962 963 for (tpindex = m[count - 1]->pindex + 1; 964 tpindex < endpindex; i++, tpindex++) { 965 p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL); 966 if (p == NULL) 967 break; 968 bp->b_pages[i] = p; 969 } 970 971 bp->b_pgafter = i - bp->b_npages; 972 bp->b_npages = i; 973 } else 974 bp->b_pgafter = 0; 975 976 if (VM_OBJECT_WOWNED(object)) 977 VM_OBJECT_WUNLOCK(object); 978 979 /* Report back actual behind/ahead read. */ 980 if (a_rbehind) 981 *a_rbehind = bp->b_pgbefore; 982 if (a_rahead) 983 *a_rahead = bp->b_pgafter; 984 985 #ifdef INVARIANTS 986 KASSERT(bp->b_npages <= nitems(bp->b_pages), 987 ("%s: buf %p overflowed", __func__, bp)); 988 for (int j = 1, prev = 0; j < bp->b_npages; j++) { 989 if (bp->b_pages[j] == bogus_page) 990 continue; 991 KASSERT(bp->b_pages[j]->pindex - bp->b_pages[prev]->pindex == 992 j - prev, ("%s: pages array not consecutive, bp %p", 993 __func__, bp)); 994 prev = j; 995 } 996 #endif 997 998 /* 999 * Recalculate first offset and bytecount with regards to read behind. 1000 * Truncate bytecount to vnode real size and round up physical size 1001 * for real devices. 1002 */ 1003 foff = IDX_TO_OFF(bp->b_pages[0]->pindex); 1004 bytecount = bp->b_npages << PAGE_SHIFT; 1005 if ((foff + bytecount) > object->un_pager.vnp.vnp_size) 1006 bytecount = object->un_pager.vnp.vnp_size - foff; 1007 secmask = bo->bo_bsize - 1; 1008 KASSERT(secmask < PAGE_SIZE && secmask > 0, 1009 ("%s: sector size %d too large", __func__, secmask + 1)); 1010 bytecount = (bytecount + secmask) & ~secmask; 1011 1012 /* 1013 * And map the pages to be read into the kva, if the filesystem 1014 * requires mapped buffers. 1015 */ 1016 if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 && 1017 unmapped_buf_allowed) { 1018 bp->b_data = unmapped_buf; 1019 bp->b_offset = 0; 1020 } else { 1021 bp->b_data = bp->b_kvabase; 1022 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages); 1023 } 1024 1025 /* Build a minimal buffer header. */ 1026 bp->b_iocmd = BIO_READ; 1027 KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred")); 1028 KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred")); 1029 bp->b_rcred = crhold(curthread->td_ucred); 1030 bp->b_wcred = crhold(curthread->td_ucred); 1031 pbgetbo(bo, bp); 1032 bp->b_vp = vp; 1033 bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount; 1034 bp->b_iooffset = dbtob(bp->b_blkno); 1035 KASSERT(IDX_TO_OFF(m[0]->pindex - bp->b_pages[0]->pindex) == 1036 (blkno0 - bp->b_blkno) * DEV_BSIZE + 1037 IDX_TO_OFF(m[0]->pindex) % bsize, 1038 ("wrong offsets bsize %d m[0] %ju b_pages[0] %ju " 1039 "blkno0 %ju b_blkno %ju", bsize, 1040 (uintmax_t)m[0]->pindex, (uintmax_t)bp->b_pages[0]->pindex, 1041 (uintmax_t)blkno0, (uintmax_t)bp->b_blkno)); 1042 1043 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 1044 VM_CNT_INC(v_vnodein); 1045 VM_CNT_ADD(v_vnodepgsin, bp->b_npages); 1046 1047 if (iodone != NULL) { /* async */ 1048 bp->b_pgiodone = iodone; 1049 bp->b_caller1 = arg; 1050 bp->b_iodone = vnode_pager_generic_getpages_done_async; 1051 bp->b_flags |= B_ASYNC; 1052 BUF_KERNPROC(bp); 1053 bstrategy(bp); 1054 return (VM_PAGER_OK); 1055 } else { 1056 bp->b_iodone = bdone; 1057 bstrategy(bp); 1058 bwait(bp, PVM, "vnread"); 1059 error = vnode_pager_generic_getpages_done(bp); 1060 for (i = 0; i < bp->b_npages; i++) 1061 bp->b_pages[i] = NULL; 1062 bp->b_vp = NULL; 1063 pbrelbo(bp); 1064 relpbuf(bp, &vnode_pbuf_freecnt); 1065 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK); 1066 } 1067 } 1068 1069 static void 1070 vnode_pager_generic_getpages_done_async(struct buf *bp) 1071 { 1072 int error; 1073 1074 error = vnode_pager_generic_getpages_done(bp); 1075 /* Run the iodone upon the requested range. */ 1076 bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore, 1077 bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error); 1078 for (int i = 0; i < bp->b_npages; i++) 1079 bp->b_pages[i] = NULL; 1080 bp->b_vp = NULL; 1081 pbrelbo(bp); 1082 relpbuf(bp, &vnode_async_pbuf_freecnt); 1083 } 1084 1085 static int 1086 vnode_pager_generic_getpages_done(struct buf *bp) 1087 { 1088 vm_object_t object; 1089 off_t tfoff, nextoff; 1090 int i, error; 1091 1092 error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0; 1093 object = bp->b_vp->v_object; 1094 1095 if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) { 1096 if (!buf_mapped(bp)) { 1097 bp->b_data = bp->b_kvabase; 1098 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, 1099 bp->b_npages); 1100 } 1101 bzero(bp->b_data + bp->b_bcount, 1102 PAGE_SIZE * bp->b_npages - bp->b_bcount); 1103 } 1104 if (buf_mapped(bp)) { 1105 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages); 1106 bp->b_data = unmapped_buf; 1107 } 1108 1109 VM_OBJECT_WLOCK(object); 1110 for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex); 1111 i < bp->b_npages; i++, tfoff = nextoff) { 1112 vm_page_t mt; 1113 1114 nextoff = tfoff + PAGE_SIZE; 1115 mt = bp->b_pages[i]; 1116 1117 if (nextoff <= object->un_pager.vnp.vnp_size) { 1118 /* 1119 * Read filled up entire page. 1120 */ 1121 mt->valid = VM_PAGE_BITS_ALL; 1122 KASSERT(mt->dirty == 0, 1123 ("%s: page %p is dirty", __func__, mt)); 1124 KASSERT(!pmap_page_is_mapped(mt), 1125 ("%s: page %p is mapped", __func__, mt)); 1126 } else { 1127 /* 1128 * Read did not fill up entire page. 1129 * 1130 * Currently we do not set the entire page valid, 1131 * we just try to clear the piece that we couldn't 1132 * read. 1133 */ 1134 vm_page_set_valid_range(mt, 0, 1135 object->un_pager.vnp.vnp_size - tfoff); 1136 KASSERT((mt->dirty & vm_page_bits(0, 1137 object->un_pager.vnp.vnp_size - tfoff)) == 0, 1138 ("%s: page %p is dirty", __func__, mt)); 1139 } 1140 1141 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter) 1142 vm_page_readahead_finish(mt); 1143 } 1144 VM_OBJECT_WUNLOCK(object); 1145 if (error != 0) 1146 printf("%s: I/O read error %d\n", __func__, error); 1147 1148 return (error); 1149 } 1150 1151 /* 1152 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 1153 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 1154 * vnode_pager_generic_putpages() to implement the previous behaviour. 1155 * 1156 * All other FS's should use the bypass to get to the local media 1157 * backing vp's VOP_PUTPAGES. 1158 */ 1159 static void 1160 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 1161 int flags, int *rtvals) 1162 { 1163 int rtval; 1164 struct vnode *vp; 1165 int bytes = count * PAGE_SIZE; 1166 1167 /* 1168 * Force synchronous operation if we are extremely low on memory 1169 * to prevent a low-memory deadlock. VOP operations often need to 1170 * allocate more memory to initiate the I/O ( i.e. do a BMAP 1171 * operation ). The swapper handles the case by limiting the amount 1172 * of asynchronous I/O, but that sort of solution doesn't scale well 1173 * for the vnode pager without a lot of work. 1174 * 1175 * Also, the backing vnode's iodone routine may not wake the pageout 1176 * daemon up. This should be probably be addressed XXX. 1177 */ 1178 1179 if (vm_page_count_min()) 1180 flags |= VM_PAGER_PUT_SYNC; 1181 1182 /* 1183 * Call device-specific putpages function 1184 */ 1185 vp = object->handle; 1186 VM_OBJECT_WUNLOCK(object); 1187 rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals); 1188 KASSERT(rtval != EOPNOTSUPP, 1189 ("vnode_pager: stale FS putpages\n")); 1190 VM_OBJECT_WLOCK(object); 1191 } 1192 1193 static int 1194 vn_off2bidx(vm_ooffset_t offset) 1195 { 1196 1197 return ((offset & PAGE_MASK) / DEV_BSIZE); 1198 } 1199 1200 static bool 1201 vn_dirty_blk(vm_page_t m, vm_ooffset_t offset) 1202 { 1203 1204 KASSERT(IDX_TO_OFF(m->pindex) <= offset && 1205 offset < IDX_TO_OFF(m->pindex + 1), 1206 ("page %p pidx %ju offset %ju", m, (uintmax_t)m->pindex, 1207 (uintmax_t)offset)); 1208 return ((m->dirty & ((vm_page_bits_t)1 << vn_off2bidx(offset))) != 0); 1209 } 1210 1211 /* 1212 * This is now called from local media FS's to operate against their 1213 * own vnodes if they fail to implement VOP_PUTPAGES. 1214 * 1215 * This is typically called indirectly via the pageout daemon and 1216 * clustering has already typically occurred, so in general we ask the 1217 * underlying filesystem to write the data out asynchronously rather 1218 * then delayed. 1219 */ 1220 int 1221 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount, 1222 int flags, int *rtvals) 1223 { 1224 vm_object_t object; 1225 vm_page_t m; 1226 vm_ooffset_t maxblksz, next_offset, poffset, prev_offset; 1227 struct uio auio; 1228 struct iovec aiov; 1229 off_t prev_resid, wrsz; 1230 int count, error, i, maxsize, ncount, pgoff, ppscheck; 1231 bool in_hole; 1232 static struct timeval lastfail; 1233 static int curfail; 1234 1235 object = vp->v_object; 1236 count = bytecount / PAGE_SIZE; 1237 1238 for (i = 0; i < count; i++) 1239 rtvals[i] = VM_PAGER_ERROR; 1240 1241 if ((int64_t)ma[0]->pindex < 0) { 1242 printf("vnode_pager_generic_putpages: " 1243 "attempt to write meta-data 0x%jx(%lx)\n", 1244 (uintmax_t)ma[0]->pindex, (u_long)ma[0]->dirty); 1245 rtvals[0] = VM_PAGER_BAD; 1246 return (VM_PAGER_BAD); 1247 } 1248 1249 maxsize = count * PAGE_SIZE; 1250 ncount = count; 1251 1252 poffset = IDX_TO_OFF(ma[0]->pindex); 1253 1254 /* 1255 * If the page-aligned write is larger then the actual file we 1256 * have to invalidate pages occurring beyond the file EOF. However, 1257 * there is an edge case where a file may not be page-aligned where 1258 * the last page is partially invalid. In this case the filesystem 1259 * may not properly clear the dirty bits for the entire page (which 1260 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 1261 * With the page locked we are free to fix-up the dirty bits here. 1262 * 1263 * We do not under any circumstances truncate the valid bits, as 1264 * this will screw up bogus page replacement. 1265 */ 1266 VM_OBJECT_RLOCK(object); 1267 if (maxsize + poffset > object->un_pager.vnp.vnp_size) { 1268 if (!VM_OBJECT_TRYUPGRADE(object)) { 1269 VM_OBJECT_RUNLOCK(object); 1270 VM_OBJECT_WLOCK(object); 1271 if (maxsize + poffset <= object->un_pager.vnp.vnp_size) 1272 goto downgrade; 1273 } 1274 if (object->un_pager.vnp.vnp_size > poffset) { 1275 maxsize = object->un_pager.vnp.vnp_size - poffset; 1276 ncount = btoc(maxsize); 1277 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 1278 pgoff = roundup2(pgoff, DEV_BSIZE); 1279 1280 /* 1281 * If the object is locked and the following 1282 * conditions hold, then the page's dirty 1283 * field cannot be concurrently changed by a 1284 * pmap operation. 1285 */ 1286 m = ma[ncount - 1]; 1287 vm_page_assert_sbusied(m); 1288 KASSERT(!pmap_page_is_write_mapped(m), 1289 ("vnode_pager_generic_putpages: page %p is not read-only", m)); 1290 MPASS(m->dirty != 0); 1291 vm_page_clear_dirty(m, pgoff, PAGE_SIZE - 1292 pgoff); 1293 } 1294 } else { 1295 maxsize = 0; 1296 ncount = 0; 1297 } 1298 for (i = ncount; i < count; i++) 1299 rtvals[i] = VM_PAGER_BAD; 1300 downgrade: 1301 VM_OBJECT_LOCK_DOWNGRADE(object); 1302 } 1303 1304 auio.uio_iov = &aiov; 1305 auio.uio_segflg = UIO_NOCOPY; 1306 auio.uio_rw = UIO_WRITE; 1307 auio.uio_td = NULL; 1308 maxblksz = roundup2(poffset + maxsize, DEV_BSIZE); 1309 1310 for (prev_offset = poffset; prev_offset < maxblksz;) { 1311 /* Skip clean blocks. */ 1312 for (in_hole = true; in_hole && prev_offset < maxblksz;) { 1313 m = ma[OFF_TO_IDX(prev_offset - poffset)]; 1314 for (i = vn_off2bidx(prev_offset); 1315 i < sizeof(vm_page_bits_t) * NBBY && 1316 prev_offset < maxblksz; i++) { 1317 if (vn_dirty_blk(m, prev_offset)) { 1318 in_hole = false; 1319 break; 1320 } 1321 prev_offset += DEV_BSIZE; 1322 } 1323 } 1324 if (in_hole) 1325 goto write_done; 1326 1327 /* Find longest run of dirty blocks. */ 1328 for (next_offset = prev_offset; next_offset < maxblksz;) { 1329 m = ma[OFF_TO_IDX(next_offset - poffset)]; 1330 for (i = vn_off2bidx(next_offset); 1331 i < sizeof(vm_page_bits_t) * NBBY && 1332 next_offset < maxblksz; i++) { 1333 if (!vn_dirty_blk(m, next_offset)) 1334 goto start_write; 1335 next_offset += DEV_BSIZE; 1336 } 1337 } 1338 start_write: 1339 if (next_offset > poffset + maxsize) 1340 next_offset = poffset + maxsize; 1341 1342 /* 1343 * Getting here requires finding a dirty block in the 1344 * 'skip clean blocks' loop. 1345 */ 1346 MPASS(prev_offset < next_offset); 1347 1348 VM_OBJECT_RUNLOCK(object); 1349 aiov.iov_base = NULL; 1350 auio.uio_iovcnt = 1; 1351 auio.uio_offset = prev_offset; 1352 prev_resid = auio.uio_resid = aiov.iov_len = next_offset - 1353 prev_offset; 1354 error = VOP_WRITE(vp, &auio, 1355 vnode_pager_putpages_ioflags(flags), curthread->td_ucred); 1356 1357 wrsz = prev_resid - auio.uio_resid; 1358 if (wrsz == 0) { 1359 if (ppsratecheck(&lastfail, &curfail, 1) != 0) { 1360 vn_printf(vp, "vnode_pager_putpages: " 1361 "zero-length write at %ju resid %zd\n", 1362 auio.uio_offset, auio.uio_resid); 1363 } 1364 VM_OBJECT_RLOCK(object); 1365 break; 1366 } 1367 1368 /* Adjust the starting offset for next iteration. */ 1369 prev_offset += wrsz; 1370 MPASS(auio.uio_offset == prev_offset); 1371 1372 ppscheck = 0; 1373 if (error != 0 && (ppscheck = ppsratecheck(&lastfail, 1374 &curfail, 1)) != 0) 1375 vn_printf(vp, "vnode_pager_putpages: I/O error %d\n", 1376 error); 1377 if (auio.uio_resid != 0 && (ppscheck != 0 || 1378 ppsratecheck(&lastfail, &curfail, 1) != 0)) 1379 vn_printf(vp, "vnode_pager_putpages: residual I/O %zd " 1380 "at %ju\n", auio.uio_resid, 1381 (uintmax_t)ma[0]->pindex); 1382 VM_OBJECT_RLOCK(object); 1383 if (error != 0 || auio.uio_resid != 0) 1384 break; 1385 } 1386 write_done: 1387 /* Mark completely processed pages. */ 1388 for (i = 0; i < OFF_TO_IDX(prev_offset - poffset); i++) 1389 rtvals[i] = VM_PAGER_OK; 1390 /* Mark partial EOF page. */ 1391 if (prev_offset == poffset + maxsize && (prev_offset & PAGE_MASK) != 0) 1392 rtvals[i++] = VM_PAGER_OK; 1393 /* Unwritten pages in range, free bonus if the page is clean. */ 1394 for (; i < ncount; i++) 1395 rtvals[i] = ma[i]->dirty == 0 ? VM_PAGER_OK : VM_PAGER_ERROR; 1396 VM_OBJECT_RUNLOCK(object); 1397 VM_CNT_ADD(v_vnodepgsout, i); 1398 VM_CNT_INC(v_vnodeout); 1399 return (rtvals[0]); 1400 } 1401 1402 int 1403 vnode_pager_putpages_ioflags(int pager_flags) 1404 { 1405 int ioflags; 1406 1407 /* 1408 * Pageouts are already clustered, use IO_ASYNC to force a 1409 * bawrite() rather then a bdwrite() to prevent paging I/O 1410 * from saturating the buffer cache. Dummy-up the sequential 1411 * heuristic to cause large ranges to cluster. If neither 1412 * IO_SYNC or IO_ASYNC is set, the system decides how to 1413 * cluster. 1414 */ 1415 ioflags = IO_VMIO; 1416 if ((pager_flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) != 0) 1417 ioflags |= IO_SYNC; 1418 else if ((pager_flags & VM_PAGER_CLUSTER_OK) == 0) 1419 ioflags |= IO_ASYNC; 1420 ioflags |= (pager_flags & VM_PAGER_PUT_INVAL) != 0 ? IO_INVAL: 0; 1421 ioflags |= (pager_flags & VM_PAGER_PUT_NOREUSE) != 0 ? IO_NOREUSE : 0; 1422 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 1423 return (ioflags); 1424 } 1425 1426 /* 1427 * vnode_pager_undirty_pages(). 1428 * 1429 * A helper to mark pages as clean after pageout that was possibly 1430 * done with a short write. The lpos argument specifies the page run 1431 * length in bytes, and the written argument specifies how many bytes 1432 * were actually written. eof is the offset past the last valid byte 1433 * in the vnode using the absolute file position of the first byte in 1434 * the run as the base from which it is computed. 1435 */ 1436 void 1437 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof, 1438 int lpos) 1439 { 1440 vm_object_t obj; 1441 int i, pos, pos_devb; 1442 1443 if (written == 0 && eof >= lpos) 1444 return; 1445 obj = ma[0]->object; 1446 VM_OBJECT_WLOCK(obj); 1447 for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) { 1448 if (pos < trunc_page(written)) { 1449 rtvals[i] = VM_PAGER_OK; 1450 vm_page_undirty(ma[i]); 1451 } else { 1452 /* Partially written page. */ 1453 rtvals[i] = VM_PAGER_AGAIN; 1454 vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK); 1455 } 1456 } 1457 if (eof >= lpos) /* avoid truncation */ 1458 goto done; 1459 for (pos = eof, i = OFF_TO_IDX(trunc_page(pos)); pos < lpos; i++) { 1460 if (pos != trunc_page(pos)) { 1461 /* 1462 * The page contains the last valid byte in 1463 * the vnode, mark the rest of the page as 1464 * clean, potentially making the whole page 1465 * clean. 1466 */ 1467 pos_devb = roundup2(pos & PAGE_MASK, DEV_BSIZE); 1468 vm_page_clear_dirty(ma[i], pos_devb, PAGE_SIZE - 1469 pos_devb); 1470 1471 /* 1472 * If the page was cleaned, report the pageout 1473 * on it as successful. msync() no longer 1474 * needs to write out the page, endlessly 1475 * creating write requests and dirty buffers. 1476 */ 1477 if (ma[i]->dirty == 0) 1478 rtvals[i] = VM_PAGER_OK; 1479 1480 pos = round_page(pos); 1481 } else { 1482 /* vm_pageout_flush() clears dirty */ 1483 rtvals[i] = VM_PAGER_BAD; 1484 pos += PAGE_SIZE; 1485 } 1486 } 1487 done: 1488 VM_OBJECT_WUNLOCK(obj); 1489 } 1490 1491 void 1492 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start, 1493 vm_offset_t end) 1494 { 1495 struct vnode *vp; 1496 vm_ooffset_t old_wm; 1497 1498 VM_OBJECT_WLOCK(object); 1499 if (object->type != OBJT_VNODE) { 1500 VM_OBJECT_WUNLOCK(object); 1501 return; 1502 } 1503 old_wm = object->un_pager.vnp.writemappings; 1504 object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start; 1505 vp = object->handle; 1506 if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) { 1507 ASSERT_VOP_ELOCKED(vp, "v_writecount inc"); 1508 VOP_ADD_WRITECOUNT(vp, 1); 1509 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 1510 __func__, vp, vp->v_writecount); 1511 } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) { 1512 ASSERT_VOP_ELOCKED(vp, "v_writecount dec"); 1513 VOP_ADD_WRITECOUNT(vp, -1); 1514 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 1515 __func__, vp, vp->v_writecount); 1516 } 1517 VM_OBJECT_WUNLOCK(object); 1518 } 1519 1520 void 1521 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start, 1522 vm_offset_t end) 1523 { 1524 struct vnode *vp; 1525 struct mount *mp; 1526 vm_offset_t inc; 1527 1528 VM_OBJECT_WLOCK(object); 1529 1530 /* 1531 * First, recheck the object type to account for the race when 1532 * the vnode is reclaimed. 1533 */ 1534 if (object->type != OBJT_VNODE) { 1535 VM_OBJECT_WUNLOCK(object); 1536 return; 1537 } 1538 1539 /* 1540 * Optimize for the case when writemappings is not going to 1541 * zero. 1542 */ 1543 inc = end - start; 1544 if (object->un_pager.vnp.writemappings != inc) { 1545 object->un_pager.vnp.writemappings -= inc; 1546 VM_OBJECT_WUNLOCK(object); 1547 return; 1548 } 1549 1550 vp = object->handle; 1551 vhold(vp); 1552 VM_OBJECT_WUNLOCK(object); 1553 mp = NULL; 1554 vn_start_write(vp, &mp, V_WAIT); 1555 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1556 1557 /* 1558 * Decrement the object's writemappings, by swapping the start 1559 * and end arguments for vnode_pager_update_writecount(). If 1560 * there was not a race with vnode reclaimation, then the 1561 * vnode's v_writecount is decremented. 1562 */ 1563 vnode_pager_update_writecount(object, end, start); 1564 VOP_UNLOCK(vp, 0); 1565 vdrop(vp); 1566 if (mp != NULL) 1567 vn_finished_write(mp); 1568 }
Cache object: 229a0788f1a21d010a3d5552f19ac4de
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