1 /* 2 * (MPSAFE) 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. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 39 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $ 40 */ 41 42 /* 43 * Page to/from files (vnodes). 44 */ 45 46 /* 47 * TODO: 48 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 49 * greatly re-simplify the vnode_pager. 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/kernel.h> 55 #include <sys/proc.h> 56 #include <sys/vnode.h> 57 #include <sys/mount.h> 58 #include <sys/buf.h> 59 #include <sys/vmmeter.h> 60 #include <sys/conf.h> 61 62 #include <cpu/lwbuf.h> 63 64 #include <vm/vm.h> 65 #include <vm/vm_object.h> 66 #include <vm/vm_page.h> 67 #include <vm/vm_pager.h> 68 #include <vm/vm_map.h> 69 #include <vm/vnode_pager.h> 70 #include <vm/swap_pager.h> 71 #include <vm/vm_extern.h> 72 73 #include <vm/vm_page2.h> 74 75 static void vnode_pager_dealloc (vm_object_t); 76 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int); 77 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, int, int *); 78 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t); 79 80 struct pagerops vnodepagerops = { 81 vnode_pager_dealloc, 82 vnode_pager_getpage, 83 vnode_pager_putpages, 84 vnode_pager_haspage 85 }; 86 87 static struct krate vbadrate = { 1 }; 88 static struct krate vresrate = { 1 }; 89 90 long vnode_pbuf_freecnt = -1; /* start out unlimited */ 91 92 /* 93 * Allocate a VM object for a vnode, typically a regular file vnode. 94 * 95 * Some additional information is required to generate a properly sized 96 * object which covers the entire buffer cache buffer straddling the file 97 * EOF. Userland does not see the extra pages as the VM fault code tests 98 * against v_filesize. 99 */ 100 vm_object_t 101 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset, 102 int blksize, int boff) 103 { 104 vm_object_t object; 105 struct vnode *vp; 106 off_t loffset; 107 vm_pindex_t lsize; 108 109 /* 110 * Pageout to vnode, no can do yet. 111 */ 112 if (handle == NULL) 113 return (NULL); 114 115 /* 116 * XXX hack - This initialization should be put somewhere else. 117 */ 118 if (vnode_pbuf_freecnt < 0) { 119 vnode_pbuf_freecnt = nswbuf_kva / 2 + 1; 120 } 121 122 /* 123 * Serialize potential vnode/object teardowns and interlocks 124 */ 125 vp = (struct vnode *)handle; 126 lwkt_gettoken(&vp->v_token); 127 128 /* 129 * If the object is being terminated, wait for it to 130 * go away. 131 */ 132 object = vp->v_object; 133 if (object) { 134 vm_object_hold(object); 135 KKASSERT((object->flags & OBJ_DEAD) == 0); 136 } 137 138 if (VREFCNT(vp) <= 0) 139 panic("vnode_pager_alloc: no vnode reference"); 140 141 /* 142 * Round up to the *next* block, then destroy the buffers in question. 143 * Since we are only removing some of the buffers we must rely on the 144 * scan count to determine whether a loop is necessary. 145 * 146 * Destroy any pages beyond the last buffer. 147 */ 148 if (boff < 0) 149 boff = (int)(length % blksize); 150 if (boff) 151 loffset = length + (blksize - boff); 152 else 153 loffset = length; 154 lsize = OFF_TO_IDX(round_page64(loffset)); 155 156 if (object == NULL) { 157 /* 158 * And an object of the appropriate size 159 */ 160 object = vm_object_allocate_hold(OBJT_VNODE, lsize); 161 object->handle = handle; 162 vp->v_object = object; 163 vp->v_filesize = length; 164 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC)) 165 vm_object_set_flag(object, OBJ_NOMSYNC); 166 vref(vp); 167 } else { 168 vm_object_reference_quick(object); /* also vref's */ 169 if (object->size != lsize) { 170 kprintf("vnode_pager_alloc: Warning, objsize " 171 "mismatch %jd/%jd vp=%p obj=%p\n", 172 (intmax_t)object->size, 173 (intmax_t)lsize, 174 vp, object); 175 } 176 if (vp->v_filesize != length) { 177 kprintf("vnode_pager_alloc: Warning, filesize " 178 "mismatch %jd/%jd vp=%p obj=%p\n", 179 (intmax_t)vp->v_filesize, 180 (intmax_t)length, 181 vp, object); 182 } 183 } 184 vm_object_drop(object); 185 lwkt_reltoken(&vp->v_token); 186 187 return (object); 188 } 189 190 /* 191 * Add a ref to a vnode's existing VM object, return the object or 192 * NULL if the vnode did not have one. This does not create the 193 * object (we can't since we don't know what the proper blocksize/boff 194 * is to match the VFS's use of the buffer cache). 195 * 196 * The vnode must be referenced and is typically open. The object should 197 * be stable in this situation. 198 * 199 * Returns the object with an additional reference but not locked. 200 */ 201 vm_object_t 202 vnode_pager_reference(struct vnode *vp) 203 { 204 vm_object_t object; 205 206 if ((object = vp->v_object) != NULL) 207 vm_object_reference_quick(object); /* also vref's vnode */ 208 return (object); 209 } 210 211 static void 212 vnode_pager_dealloc(vm_object_t object) 213 { 214 struct vnode *vp = object->handle; 215 216 if (vp == NULL) 217 panic("vnode_pager_dealloc: pager already dealloced"); 218 219 vm_object_pip_wait(object, "vnpdea"); 220 221 object->handle = NULL; 222 object->type = OBJT_DEAD; 223 vp->v_object = NULL; 224 vp->v_filesize = NOOFFSET; 225 vclrflags(vp, VTEXT | VOBJBUF); 226 swap_pager_freespace_all(object); 227 } 228 229 /* 230 * Return whether the vnode pager has the requested page. Return the 231 * number of disk-contiguous pages before and after the requested page, 232 * not including the requested page. 233 */ 234 static boolean_t 235 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex) 236 { 237 struct vnode *vp = object->handle; 238 off_t loffset; 239 off_t doffset; 240 int voff; 241 int bsize; 242 int error; 243 244 /* 245 * If no vp or vp is doomed or marked transparent to VM, we do not 246 * have the page. 247 */ 248 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 249 return FALSE; 250 251 /* 252 * If filesystem no longer mounted or offset beyond end of file we do 253 * not have the page. 254 */ 255 loffset = IDX_TO_OFF(pindex); 256 257 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 258 return FALSE; 259 260 bsize = vp->v_mount->mnt_stat.f_iosize; 261 voff = loffset % bsize; 262 263 /* 264 * XXX 265 * 266 * BMAP returns byte counts before and after, where after 267 * is inclusive of the base page. haspage must return page 268 * counts before and after where after does not include the 269 * base page. 270 * 271 * BMAP is allowed to return a *after of 0 for backwards 272 * compatibility. The base page is still considered valid if 273 * no error is returned. 274 */ 275 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0); 276 if (error) 277 return TRUE; 278 if (doffset == NOOFFSET) 279 return FALSE; 280 return TRUE; 281 } 282 283 /* 284 * Lets the VM system know about a change in size for a file. 285 * We adjust our own internal size and flush any cached pages in 286 * the associated object that are affected by the size change. 287 * 288 * NOTE: This routine may be invoked as a result of a pager put 289 * operation (possibly at object termination time), so we must be careful. 290 * 291 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 292 * we do not blow up on the case. nsize will always be >= 0, however. 293 */ 294 void 295 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 296 { 297 vm_pindex_t nobjsize; 298 vm_pindex_t oobjsize; 299 vm_object_t object; 300 301 object = vp->v_object; 302 if (object == NULL) 303 return; 304 vm_object_hold(object); 305 KKASSERT(vp->v_object == object); 306 307 /* 308 * Hasn't changed size 309 */ 310 if (nsize == vp->v_filesize) { 311 vm_object_drop(object); 312 return; 313 } 314 315 /* 316 * Has changed size. Adjust the VM object's size and v_filesize 317 * before we start scanning pages to prevent new pages from being 318 * allocated during the scan. 319 */ 320 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 321 oobjsize = object->size; 322 object->size = nobjsize; 323 324 /* 325 * File has shrunk. Toss any cached pages beyond the new EOF. 326 */ 327 if (nsize < vp->v_filesize) { 328 vp->v_filesize = nsize; 329 if (nobjsize < oobjsize) { 330 vm_object_page_remove(object, nobjsize, oobjsize, 331 FALSE); 332 } 333 /* 334 * This gets rid of garbage at the end of a page that is now 335 * only partially backed by the vnode. Since we are setting 336 * the entire page valid & clean after we are done we have 337 * to be sure that the portion of the page within the file 338 * bounds is already valid. If it isn't then making it 339 * valid would create a corrupt block. 340 */ 341 if (nsize & PAGE_MASK) { 342 vm_offset_t kva; 343 vm_page_t m; 344 345 m = vm_page_lookup_busy_wait(object, OFF_TO_IDX(nsize), 346 TRUE, "vsetsz"); 347 348 if (m && m->valid) { 349 int base = (int)nsize & PAGE_MASK; 350 int size = PAGE_SIZE - base; 351 struct lwbuf *lwb; 352 struct lwbuf lwb_cache; 353 354 /* 355 * Clear out partial-page garbage in case 356 * the page has been mapped. 357 * 358 * This is byte aligned. 359 */ 360 lwb = lwbuf_alloc(m, &lwb_cache); 361 kva = lwbuf_kva(lwb); 362 bzero((caddr_t)kva + base, size); 363 lwbuf_free(lwb); 364 365 /* 366 * XXX work around SMP data integrity race 367 * by unmapping the page from user processes. 368 * The garbage we just cleared may be mapped 369 * to a user process running on another cpu 370 * and this code is not running through normal 371 * I/O channels which handle SMP issues for 372 * us, so unmap page to synchronize all cpus. 373 * 374 * XXX should vm_pager_unmap_page() have 375 * dealt with this? 376 */ 377 vm_page_protect(m, VM_PROT_NONE); 378 379 /* 380 * Clear out partial-page dirty bits. This 381 * has the side effect of setting the valid 382 * bits, but that is ok. There are a bunch 383 * of places in the VM system where we expected 384 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 385 * case is one of them. If the page is still 386 * partially dirty, make it fully dirty. 387 * 388 * NOTE: We do not clear out the valid 389 * bits. This would prevent bogus_page 390 * replacement from working properly. 391 * 392 * NOTE: We do not want to clear the dirty 393 * bit for a partial DEV_BSIZE'd truncation! 394 * This is DEV_BSIZE aligned! 395 */ 396 vm_page_clear_dirty_beg_nonincl(m, base, size); 397 if (m->dirty != 0) 398 m->dirty = VM_PAGE_BITS_ALL; 399 vm_page_wakeup(m); 400 } else if (m) { 401 vm_page_wakeup(m); 402 } 403 } 404 } else { 405 vp->v_filesize = nsize; 406 } 407 vm_object_drop(object); 408 } 409 410 /* 411 * Release a page busied for a getpages operation. The page may have become 412 * wired (typically due to being used by the buffer cache) or otherwise been 413 * soft-busied and cannot be freed in that case. A held page can still be 414 * freed. 415 */ 416 void 417 vnode_pager_freepage(vm_page_t m) 418 { 419 if ((m->busy_count & PBUSY_MASK) || 420 m->wire_count || 421 (m->flags & PG_NEED_COMMIT)) { 422 vm_page_activate(m); 423 vm_page_wakeup(m); 424 } else { 425 vm_page_free(m); 426 } 427 } 428 429 /* 430 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 431 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 432 * vnode_pager_generic_getpages() to implement the previous behaviour. 433 * 434 * All other FS's should use the bypass to get to the local media 435 * backing vp's VOP_GETPAGES. 436 */ 437 static int 438 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 439 { 440 int rtval; 441 struct vnode *vp; 442 443 vp = object->handle; 444 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess); 445 if (rtval == EOPNOTSUPP) 446 panic("vnode_pager: vfs's must implement vop_getpages"); 447 return rtval; 448 } 449 450 /* 451 * This is now called from local media FS's to operate against their 452 * own vnodes if they fail to implement VOP_GETPAGES. 453 * 454 * With all the caching local media devices do these days there is really 455 * very little point to attempting to restrict the I/O size to contiguous 456 * blocks on-disk, especially if our caller thinks we need all the specified 457 * pages. Just construct and issue a READ. 458 */ 459 int 460 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount, 461 int reqpage, int seqaccess) 462 { 463 struct iovec aiov; 464 struct uio auio; 465 off_t foff; 466 int error; 467 int count; 468 int i; 469 int ioflags; 470 int obytecount; 471 472 /* 473 * Do not do anything if the vnode is bad. 474 */ 475 if (vp->v_mount == NULL) 476 return VM_PAGER_BAD; 477 478 /* 479 * Calculate the number of pages. Since we are paging in whole 480 * pages, adjust bytecount to be an integral multiple of the page 481 * size. It will be clipped to the file EOF later on. 482 */ 483 bytecount = round_page(bytecount); 484 count = bytecount / PAGE_SIZE; 485 486 /* 487 * We could check m[reqpage]->valid here and shortcut the operation, 488 * but doing so breaks read-ahead. Instead assume that the VM 489 * system has already done at least the check, don't worry about 490 * any races, and issue the VOP_READ to allow read-ahead to function. 491 * 492 * This keeps the pipeline full for I/O bound sequentially scanned 493 * mmap()'s 494 */ 495 /* don't shortcut */ 496 497 /* 498 * Discard pages past the file EOF. If the requested page is past 499 * the file EOF we just leave its valid bits set to 0, the caller 500 * expects to maintain ownership of the requested page. If the 501 * entire range is past file EOF discard everything and generate 502 * a pagein error. 503 */ 504 foff = IDX_TO_OFF(mpp[0]->pindex); 505 if (foff >= vp->v_filesize) { 506 for (i = 0; i < count; i++) { 507 if (i != reqpage) 508 vnode_pager_freepage(mpp[i]); 509 } 510 return VM_PAGER_ERROR; 511 } 512 513 if (foff + bytecount > vp->v_filesize) { 514 bytecount = vp->v_filesize - foff; 515 i = round_page(bytecount) / PAGE_SIZE; 516 while (count > i) { 517 --count; 518 if (count != reqpage) 519 vnode_pager_freepage(mpp[count]); 520 } 521 } 522 523 /* 524 * The size of the transfer is bytecount. bytecount will be an 525 * integral multiple of the page size unless it has been clipped 526 * to the file EOF. The transfer cannot exceed the file EOF. 527 * 528 * When dealing with real devices we must round-up to the device 529 * sector size. 530 */ 531 if (vp->v_type == VBLK || vp->v_type == VCHR) { 532 int secmask = vp->v_rdev->si_bsize_phys - 1; 533 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large", secmask + 1)); 534 bytecount = (bytecount + secmask) & ~secmask; 535 } 536 obytecount = bytecount; 537 538 /* 539 * Severe hack to avoid deadlocks with the buffer cache 540 */ 541 for (i = 0; i < count; ++i) { 542 vm_page_t mt = mpp[i]; 543 544 vm_page_io_start(mt); 545 vm_page_wakeup(mt); 546 } 547 548 /* 549 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE 550 */ 551 ioflags = IO_VMIO; 552 if (seqaccess) 553 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 554 555 aiov.iov_base = NULL; 556 aiov.iov_len = bytecount; 557 auio.uio_iov = &aiov; 558 auio.uio_iovcnt = 1; 559 auio.uio_offset = foff; 560 auio.uio_segflg = UIO_NOCOPY; 561 auio.uio_rw = UIO_READ; 562 auio.uio_resid = bytecount; 563 auio.uio_td = NULL; 564 mycpu->gd_cnt.v_vnodein++; 565 mycpu->gd_cnt.v_vnodepgsin += count; 566 567 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 568 569 /* 570 * Severe hack to avoid deadlocks with the buffer cache 571 */ 572 for (i = 0; i < count; ++i) { 573 vm_page_busy_wait(mpp[i], FALSE, "getpgs"); 574 vm_page_io_finish(mpp[i]); 575 } 576 577 /* 578 * Calculate the actual number of bytes read and clean up the 579 * page list. 580 */ 581 bytecount -= auio.uio_resid; 582 583 for (i = 0; i < count; ++i) { 584 vm_page_t mt = mpp[i]; 585 586 if (i != reqpage) { 587 if (error == 0 && mt->valid) { 588 if (mt->flags & PG_REFERENCED) 589 vm_page_activate(mt); 590 else 591 vm_page_deactivate(mt); 592 vm_page_wakeup(mt); 593 } else { 594 vnode_pager_freepage(mt); 595 } 596 } else if (mt->valid == 0) { 597 if (error == 0) { 598 kprintf("page failed but no I/O error page " 599 "%p object %p pindex %d\n", 600 mt, mt->object, (int) mt->pindex); 601 kprintf("i=%d foff=%016lx bytecount=%d/%d " 602 "uioresid=%zd\n", 603 i, foff, obytecount, bytecount, 604 auio.uio_resid); 605 /* whoops, something happened */ 606 error = EINVAL; 607 } 608 } else if (mt->valid != VM_PAGE_BITS_ALL) { 609 /* 610 * Zero-extend the requested page if necessary (if 611 * the filesystem is using a small block size). 612 */ 613 vm_page_zero_invalid(mt, TRUE); 614 } 615 } 616 if (error) { 617 kprintf("vnode_pager_getpage: I/O read error\n"); 618 } 619 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 620 } 621 622 /* 623 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 624 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 625 * vnode_pager_generic_putpages() to implement the previous behaviour. 626 * 627 * Caller has already cleared the pmap modified bits, if any. 628 * 629 * All other FS's should use the bypass to get to the local media 630 * backing vp's VOP_PUTPAGES. 631 */ 632 static void 633 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 634 int sync, int *rtvals) 635 { 636 int rtval; 637 struct vnode *vp; 638 int bytes = count * PAGE_SIZE; 639 640 /* 641 * Force synchronous operation if we are extremely low on memory 642 * to prevent a low-memory deadlock. VOP operations often need to 643 * allocate more memory to initiate the I/O ( i.e. do a BMAP 644 * operation ). The swapper handles the case by limiting the amount 645 * of asynchronous I/O, but that sort of solution doesn't scale well 646 * for the vnode pager without a lot of work. 647 * 648 * Also, the backing vnode's iodone routine may not wake the pageout 649 * daemon up. This should be probably be addressed XXX. 650 */ 651 652 if ((vmstats.v_free_count + vmstats.v_cache_count) < 653 vmstats.v_pageout_free_min) { 654 sync |= OBJPC_SYNC; 655 } 656 657 /* 658 * Call device-specific putpages function 659 */ 660 vp = object->handle; 661 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 662 if (rtval == EOPNOTSUPP) { 663 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 664 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 665 } 666 } 667 668 669 /* 670 * This is now called from local media FS's to operate against their 671 * own vnodes if they fail to implement VOP_PUTPAGES. 672 * 673 * This is typically called indirectly via the pageout daemon and 674 * clustering has already typically occured, so in general we ask the 675 * underlying filesystem to write the data out asynchronously rather 676 * then delayed. 677 */ 678 int 679 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 680 int flags, int *rtvals) 681 { 682 int i; 683 int maxsize, ncount, count; 684 vm_ooffset_t poffset; 685 struct uio auio; 686 struct iovec aiov; 687 int error; 688 int ioflags; 689 690 count = bytecount / PAGE_SIZE; 691 692 for (i = 0; i < count; i++) 693 rtvals[i] = VM_PAGER_AGAIN; 694 695 if ((int) m[0]->pindex < 0) { 696 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 697 (long)m[0]->pindex, m[0]->dirty); 698 rtvals[0] = VM_PAGER_BAD; 699 return VM_PAGER_BAD; 700 } 701 702 maxsize = count * PAGE_SIZE; 703 ncount = count; 704 705 poffset = IDX_TO_OFF(m[0]->pindex); 706 707 /* 708 * If the page-aligned write is larger then the actual file we 709 * have to invalidate pages occuring beyond the file EOF. 710 * 711 * If the file EOF resides in the middle of a page we still clear 712 * all of that page's dirty bits later on. If we didn't it would 713 * endlessly re-write. 714 * 715 * We do not under any circumstances truncate the valid bits, as 716 * this will screw up bogus page replacement. 717 * 718 * The caller has already read-protected the pages. The VFS must 719 * use the buffer cache to wrap the pages. The pages might not 720 * be immediately flushed by the buffer cache but once under its 721 * control the pages themselves can wind up being marked clean 722 * and their covering buffer cache buffer can be marked dirty. 723 */ 724 if (poffset + maxsize > vp->v_filesize) { 725 if (poffset < vp->v_filesize) { 726 maxsize = vp->v_filesize - poffset; 727 ncount = btoc(maxsize); 728 } else { 729 maxsize = 0; 730 ncount = 0; 731 } 732 if (ncount < count) { 733 for (i = ncount; i < count; i++) { 734 rtvals[i] = VM_PAGER_BAD; 735 } 736 } 737 } 738 739 /* 740 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 741 * rather then a bdwrite() to prevent paging I/O from saturating 742 * the buffer cache. Dummy-up the sequential heuristic to cause 743 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 744 * the system decides how to cluster. 745 */ 746 ioflags = IO_VMIO; 747 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 748 ioflags |= IO_SYNC; 749 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 750 ioflags |= IO_ASYNC; 751 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 752 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 753 754 aiov.iov_base = (caddr_t) 0; 755 aiov.iov_len = maxsize; 756 auio.uio_iov = &aiov; 757 auio.uio_iovcnt = 1; 758 auio.uio_offset = poffset; 759 auio.uio_segflg = UIO_NOCOPY; 760 auio.uio_rw = UIO_WRITE; 761 auio.uio_resid = maxsize; 762 auio.uio_td = NULL; 763 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 764 mycpu->gd_cnt.v_vnodeout++; 765 mycpu->gd_cnt.v_vnodepgsout += ncount; 766 767 if (error) { 768 krateprintf(&vbadrate, 769 "vnode_pager_putpages: I/O error %d\n", error); 770 } 771 if (auio.uio_resid) { 772 krateprintf(&vresrate, 773 "vnode_pager_putpages: residual I/O %zd at %lu\n", 774 auio.uio_resid, (u_long)m[0]->pindex); 775 } 776 if (error == 0) { 777 for (i = 0; i < ncount; i++) { 778 rtvals[i] = VM_PAGER_OK; 779 vm_page_undirty(m[i]); 780 } 781 } 782 return rtvals[0]; 783 } 784 785 /* 786 * Run the chain and if the bottom-most object is a vnode-type lock the 787 * underlying vnode. A locked vnode or NULL is returned. 788 */ 789 struct vnode * 790 vnode_pager_lock(vm_object_t object) 791 { 792 struct vnode *vp = NULL; 793 vm_object_t lobject; 794 vm_object_t tobject; 795 int error; 796 797 if (object == NULL) 798 return(NULL); 799 800 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 801 lobject = object; 802 803 while (lobject->type != OBJT_VNODE) { 804 if (lobject->flags & OBJ_DEAD) 805 break; 806 tobject = lobject->backing_object; 807 if (tobject == NULL) 808 break; 809 vm_object_hold_shared(tobject); 810 if (tobject == lobject->backing_object) { 811 if (lobject != object) { 812 vm_object_lock_swap(); 813 vm_object_drop(lobject); 814 } 815 lobject = tobject; 816 } else { 817 vm_object_drop(tobject); 818 } 819 } 820 while (lobject->type == OBJT_VNODE && 821 (lobject->flags & OBJ_DEAD) == 0) { 822 /* 823 * Extract the vp 824 */ 825 vp = lobject->handle; 826 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 827 if (error == 0) { 828 if (lobject->handle == vp) 829 break; 830 vput(vp); 831 } else { 832 kprintf("vnode_pager_lock: vp %p error %d " 833 "lockstatus %d, retrying\n", 834 vp, error, 835 lockstatus(&vp->v_lock, curthread)); 836 tsleep(object->handle, 0, "vnpgrl", hz); 837 } 838 vp = NULL; 839 } 840 if (lobject != object) 841 vm_object_drop(lobject); 842 return (vp); 843 } 844