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 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $ 42 * $DragonFly: src/sys/vm/vnode_pager.c,v 1.43 2008/06/19 23:27:39 dillon Exp $ 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/param.h> 56 #include <sys/systm.h> 57 #include <sys/kernel.h> 58 #include <sys/proc.h> 59 #include <sys/vnode.h> 60 #include <sys/mount.h> 61 #include <sys/buf.h> 62 #include <sys/vmmeter.h> 63 #include <sys/conf.h> 64 #include <sys/sfbuf.h> 65 #include <sys/thread2.h> 66 67 #include <vm/vm.h> 68 #include <vm/vm_object.h> 69 #include <vm/vm_page.h> 70 #include <vm/vm_pager.h> 71 #include <vm/vm_map.h> 72 #include <vm/vnode_pager.h> 73 #include <vm/vm_extern.h> 74 75 static void vnode_pager_dealloc (vm_object_t); 76 static int vnode_pager_getpages (vm_object_t, vm_page_t *, int, int); 77 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *); 78 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t, int *, int *); 79 80 struct pagerops vnodepagerops = { 81 NULL, 82 vnode_pager_alloc, 83 vnode_pager_dealloc, 84 vnode_pager_getpages, 85 vnode_pager_putpages, 86 vnode_pager_haspage, 87 NULL 88 }; 89 90 static struct krate vbadrate = { 1 }; 91 static struct krate vresrate = { 1 }; 92 93 int vnode_pbuf_freecnt = -1; /* start out unlimited */ 94 95 /* 96 * Allocate (or lookup) pager for a vnode. 97 * Handle is a vnode pointer. 98 */ 99 vm_object_t 100 vnode_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t offset) 101 { 102 vm_object_t object; 103 struct vnode *vp; 104 105 /* 106 * Pageout to vnode, no can do yet. 107 */ 108 if (handle == NULL) 109 return (NULL); 110 111 /* 112 * XXX hack - This initialization should be put somewhere else. 113 */ 114 if (vnode_pbuf_freecnt < 0) { 115 vnode_pbuf_freecnt = nswbuf / 2 + 1; 116 } 117 118 vp = (struct vnode *) handle; 119 120 /* 121 * Prevent race condition when allocating the object. This 122 * can happen with NFS vnodes since the nfsnode isn't locked. 123 */ 124 while (vp->v_flag & VOLOCK) { 125 vp->v_flag |= VOWANT; 126 tsleep(vp, 0, "vnpobj", 0); 127 } 128 vp->v_flag |= VOLOCK; 129 130 /* 131 * If the object is being terminated, wait for it to 132 * go away. 133 */ 134 while (((object = vp->v_object) != NULL) && 135 (object->flags & OBJ_DEAD)) { 136 vm_object_dead_sleep(object, "vadead"); 137 } 138 139 if (vp->v_sysref.refcnt <= 0) 140 panic("vnode_pager_alloc: no vnode reference"); 141 142 if (object == NULL) { 143 /* 144 * And an object of the appropriate size 145 */ 146 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 147 object->flags = 0; 148 object->handle = handle; 149 vp->v_object = object; 150 vp->v_filesize = size; 151 } else { 152 object->ref_count++; 153 if (vp->v_filesize != size) { 154 kprintf("vnode_pager_alloc: Warning, filesize " 155 "mismatch %lld/%lld\n", 156 (long long)vp->v_filesize, 157 (long long)size); 158 } 159 } 160 vref(vp); 161 162 vp->v_flag &= ~VOLOCK; 163 if (vp->v_flag & VOWANT) { 164 vp->v_flag &= ~VOWANT; 165 wakeup(vp); 166 } 167 return (object); 168 } 169 170 static void 171 vnode_pager_dealloc(vm_object_t object) 172 { 173 struct vnode *vp = object->handle; 174 175 if (vp == NULL) 176 panic("vnode_pager_dealloc: pager already dealloced"); 177 178 vm_object_pip_wait(object, "vnpdea"); 179 180 object->handle = NULL; 181 object->type = OBJT_DEAD; 182 vp->v_object = NULL; 183 vp->v_filesize = NOOFFSET; 184 vp->v_flag &= ~(VTEXT | VOBJBUF); 185 } 186 187 /* 188 * Return whether the vnode pager has the requested page. Return the 189 * number of disk-contiguous pages before and after the requested page, 190 * not including the requested page. 191 */ 192 static boolean_t 193 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 194 int *after) 195 { 196 struct vnode *vp = object->handle; 197 off_t loffset; 198 off_t doffset; 199 int voff; 200 int bsize; 201 int error; 202 203 /* 204 * If no vp or vp is doomed or marked transparent to VM, we do not 205 * have the page. 206 */ 207 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 208 return FALSE; 209 210 /* 211 * If filesystem no longer mounted or offset beyond end of file we do 212 * not have the page. 213 */ 214 loffset = IDX_TO_OFF(pindex); 215 216 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 217 return FALSE; 218 219 bsize = vp->v_mount->mnt_stat.f_iosize; 220 voff = loffset % bsize; 221 222 /* 223 * BMAP returns byte counts before and after, where after 224 * is inclusive of the base page. haspage must return page 225 * counts before and after where after does not include the 226 * base page. 227 * 228 * BMAP is allowed to return a *after of 0 for backwards 229 * compatibility. The base page is still considered valid if 230 * no error is returned. 231 */ 232 error = VOP_BMAP(vp, loffset - voff, &doffset, after, before, 0); 233 if (error) { 234 if (before) 235 *before = 0; 236 if (after) 237 *after = 0; 238 return TRUE; 239 } 240 if (doffset == NOOFFSET) 241 return FALSE; 242 243 if (before) { 244 *before = (*before + voff) >> PAGE_SHIFT; 245 } 246 if (after) { 247 *after -= voff; 248 if (loffset + *after > vp->v_filesize) 249 *after = vp->v_filesize - loffset; 250 *after >>= PAGE_SHIFT; 251 if (*after < 0) 252 *after = 0; 253 } 254 return TRUE; 255 } 256 257 /* 258 * Lets the VM system know about a change in size for a file. 259 * We adjust our own internal size and flush any cached pages in 260 * the associated object that are affected by the size change. 261 * 262 * NOTE: This routine may be invoked as a result of a pager put 263 * operation (possibly at object termination time), so we must be careful. 264 * 265 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 266 * we do not blow up on the case. nsize will always be >= 0, however. 267 */ 268 void 269 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 270 { 271 vm_pindex_t nobjsize; 272 vm_pindex_t oobjsize; 273 vm_object_t object = vp->v_object; 274 275 if (object == NULL) 276 return; 277 278 /* 279 * Hasn't changed size 280 */ 281 if (nsize == vp->v_filesize) 282 return; 283 284 /* 285 * Has changed size. Adjust the VM object's size and v_filesize 286 * before we start scanning pages to prevent new pages from being 287 * allocated during the scan. 288 */ 289 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 290 oobjsize = object->size; 291 object->size = nobjsize; 292 293 /* 294 * File has shrunk. Toss any cached pages beyond the new EOF. 295 */ 296 if (nsize < vp->v_filesize) { 297 vp->v_filesize = nsize; 298 if (nobjsize < oobjsize) { 299 vm_object_page_remove(object, nobjsize, oobjsize, 300 FALSE); 301 } 302 /* 303 * This gets rid of garbage at the end of a page that is now 304 * only partially backed by the vnode. Since we are setting 305 * the entire page valid & clean after we are done we have 306 * to be sure that the portion of the page within the file 307 * bounds is already valid. If it isn't then making it 308 * valid would create a corrupt block. 309 */ 310 if (nsize & PAGE_MASK) { 311 vm_offset_t kva; 312 vm_page_t m; 313 314 do { 315 m = vm_page_lookup(object, OFF_TO_IDX(nsize)); 316 } while (m && vm_page_sleep_busy(m, TRUE, "vsetsz")); 317 318 if (m && m->valid) { 319 int base = (int)nsize & PAGE_MASK; 320 int size = PAGE_SIZE - base; 321 struct sf_buf *sf; 322 323 /* 324 * Clear out partial-page garbage in case 325 * the page has been mapped. 326 */ 327 vm_page_busy(m); 328 sf = sf_buf_alloc(m, SFB_CPUPRIVATE); 329 kva = sf_buf_kva(sf); 330 bzero((caddr_t)kva + base, size); 331 sf_buf_free(sf); 332 333 /* 334 * XXX work around SMP data integrity race 335 * by unmapping the page from user processes. 336 * The garbage we just cleared may be mapped 337 * to a user process running on another cpu 338 * and this code is not running through normal 339 * I/O channels which handle SMP issues for 340 * us, so unmap page to synchronize all cpus. 341 * 342 * XXX should vm_pager_unmap_page() have 343 * dealt with this? 344 */ 345 vm_page_protect(m, VM_PROT_NONE); 346 347 /* 348 * Clear out partial-page dirty bits. This 349 * has the side effect of setting the valid 350 * bits, but that is ok. There are a bunch 351 * of places in the VM system where we expected 352 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 353 * case is one of them. If the page is still 354 * partially dirty, make it fully dirty. 355 * 356 * note that we do not clear out the valid 357 * bits. This would prevent bogus_page 358 * replacement from working properly. 359 */ 360 vm_page_set_validclean(m, base, size); 361 if (m->dirty != 0) 362 m->dirty = VM_PAGE_BITS_ALL; 363 vm_page_wakeup(m); 364 } 365 } 366 } else { 367 vp->v_filesize = nsize; 368 } 369 } 370 371 /* 372 * Release a page busied for a getpages operation. The page may have become 373 * wired (typically due to being used by the buffer cache) or otherwise been 374 * soft-busied and cannot be freed in that case. A held page can still be 375 * freed. 376 */ 377 void 378 vnode_pager_freepage(vm_page_t m) 379 { 380 if (m->busy || m->wire_count) { 381 vm_page_activate(m); 382 vm_page_wakeup(m); 383 } else { 384 vm_page_free(m); 385 } 386 } 387 388 /* 389 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 390 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 391 * vnode_pager_generic_getpages() to implement the previous behaviour. 392 * 393 * All other FS's should use the bypass to get to the local media 394 * backing vp's VOP_GETPAGES. 395 */ 396 static int 397 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 398 { 399 int rtval; 400 struct vnode *vp; 401 int bytes = count * PAGE_SIZE; 402 403 vp = object->handle; 404 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 405 if (rtval == EOPNOTSUPP) 406 panic("vnode_pager: vfs's must implement vop_getpages\n"); 407 return rtval; 408 } 409 410 /* 411 * This is now called from local media FS's to operate against their 412 * own vnodes if they fail to implement VOP_GETPAGES. 413 * 414 * With all the caching local media devices do these days there is really 415 * very little point to attempting to restrict the I/O size to contiguous 416 * blocks on-disk, especially if our caller thinks we need all the specified 417 * pages. Just construct and issue a READ. 418 */ 419 int 420 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount, 421 int reqpage) 422 { 423 struct iovec aiov; 424 struct uio auio; 425 off_t foff; 426 int error; 427 int count; 428 int i; 429 int ioflags; 430 431 /* 432 * Do not do anything if the vnode is bad. 433 */ 434 if (vp->v_mount == NULL) 435 return VM_PAGER_BAD; 436 437 /* 438 * Calculate the number of pages. Since we are paging in whole 439 * pages, adjust bytecount to be an integral multiple of the page 440 * size. It will be clipped to the file EOF later on. 441 */ 442 bytecount = round_page(bytecount); 443 count = bytecount / PAGE_SIZE; 444 445 /* 446 * If we have a completely valid page available to us, we can 447 * clean up and return. Otherwise we have to re-read the 448 * media. 449 * 450 * Note that this does not work with NFS, so NFS has its own 451 * getpages routine. The problem is that NFS can have partially 452 * valid pages associated with the buffer cache due to the piecemeal 453 * write support. If we were to fall through and re-read the media 454 * as we do here, dirty data could be lost. 455 */ 456 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 457 for (i = 0; i < count; i++) { 458 if (i != reqpage) 459 vnode_pager_freepage(m[i]); 460 } 461 return VM_PAGER_OK; 462 } 463 464 /* 465 * Discard pages past the file EOF. If the requested page is past 466 * the file EOF we just leave its valid bits set to 0, the caller 467 * expects to maintain ownership of the requested page. If the 468 * entire range is past file EOF discard everything and generate 469 * a pagein error. 470 */ 471 foff = IDX_TO_OFF(m[0]->pindex); 472 if (foff >= vp->v_filesize) { 473 for (i = 0; i < count; i++) { 474 if (i != reqpage) 475 vnode_pager_freepage(m[i]); 476 } 477 return VM_PAGER_ERROR; 478 } 479 480 if (foff + bytecount > vp->v_filesize) { 481 bytecount = vp->v_filesize - foff; 482 i = round_page(bytecount) / PAGE_SIZE; 483 while (count > i) { 484 --count; 485 if (count != reqpage) 486 vnode_pager_freepage(m[count]); 487 } 488 } 489 490 /* 491 * The size of the transfer is bytecount. bytecount will be an 492 * integral multiple of the page size unless it has been clipped 493 * to the file EOF. The transfer cannot exceed the file EOF. 494 * 495 * When dealing with real devices we must round-up to the device 496 * sector size. 497 */ 498 if (vp->v_type == VBLK || vp->v_type == VCHR) { 499 int secmask = vp->v_rdev->si_bsize_phys - 1; 500 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 501 bytecount = (bytecount + secmask) & ~secmask; 502 } 503 504 /* 505 * Severe hack to avoid deadlocks with the buffer cache 506 */ 507 for (i = 0; i < count; ++i) { 508 vm_page_t mt = m[i]; 509 510 vm_page_io_start(mt); 511 vm_page_wakeup(mt); 512 } 513 514 /* 515 * Issue the I/O without any read-ahead 516 */ 517 ioflags = IO_VMIO; 518 /*ioflags |= IO_SEQMAX << IO_SEQSHIFT;*/ 519 520 aiov.iov_base = (caddr_t) 0; 521 aiov.iov_len = bytecount; 522 auio.uio_iov = &aiov; 523 auio.uio_iovcnt = 1; 524 auio.uio_offset = foff; 525 auio.uio_segflg = UIO_NOCOPY; 526 auio.uio_rw = UIO_READ; 527 auio.uio_resid = bytecount; 528 auio.uio_td = NULL; 529 mycpu->gd_cnt.v_vnodein++; 530 mycpu->gd_cnt.v_vnodepgsin += count; 531 532 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 533 534 /* 535 * Severe hack to avoid deadlocks with the buffer cache 536 */ 537 for (i = 0; i < count; ++i) { 538 vm_page_t mt = m[i]; 539 540 while (vm_page_sleep_busy(mt, FALSE, "getpgs")) 541 ; 542 vm_page_busy(mt); 543 vm_page_io_finish(mt); 544 } 545 546 /* 547 * Calculate the actual number of bytes read and clean up the 548 * page list. 549 */ 550 bytecount -= auio.uio_resid; 551 552 for (i = 0; i < count; ++i) { 553 vm_page_t mt = m[i]; 554 555 if (i != reqpage) { 556 if (error == 0 && mt->valid) { 557 if (mt->flags & PG_WANTED) 558 vm_page_activate(mt); 559 else 560 vm_page_deactivate(mt); 561 vm_page_wakeup(mt); 562 } else { 563 vnode_pager_freepage(mt); 564 } 565 } else if (mt->valid == 0) { 566 if (error == 0) { 567 kprintf("page failed but no I/O error page %p object %p pindex %d\n", mt, mt->object, (int) mt->pindex); 568 /* whoops, something happened */ 569 error = EINVAL; 570 } 571 } else if (mt->valid != VM_PAGE_BITS_ALL) { 572 /* 573 * Zero-extend the requested page if necessary (if 574 * the filesystem is using a small block size). 575 */ 576 vm_page_zero_invalid(mt, TRUE); 577 } 578 } 579 if (error) { 580 kprintf("vnode_pager_getpages: I/O read error\n"); 581 } 582 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 583 } 584 585 /* 586 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 587 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 588 * vnode_pager_generic_putpages() to implement the previous behaviour. 589 * 590 * All other FS's should use the bypass to get to the local media 591 * backing vp's VOP_PUTPAGES. 592 */ 593 static void 594 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 595 boolean_t sync, int *rtvals) 596 { 597 int rtval; 598 struct vnode *vp; 599 int bytes = count * PAGE_SIZE; 600 601 /* 602 * Force synchronous operation if we are extremely low on memory 603 * to prevent a low-memory deadlock. VOP operations often need to 604 * allocate more memory to initiate the I/O ( i.e. do a BMAP 605 * operation ). The swapper handles the case by limiting the amount 606 * of asynchronous I/O, but that sort of solution doesn't scale well 607 * for the vnode pager without a lot of work. 608 * 609 * Also, the backing vnode's iodone routine may not wake the pageout 610 * daemon up. This should be probably be addressed XXX. 611 */ 612 613 if ((vmstats.v_free_count + vmstats.v_cache_count) < vmstats.v_pageout_free_min) 614 sync |= OBJPC_SYNC; 615 616 /* 617 * Call device-specific putpages function 618 */ 619 620 vp = object->handle; 621 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 622 if (rtval == EOPNOTSUPP) { 623 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 624 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 625 } 626 } 627 628 629 /* 630 * This is now called from local media FS's to operate against their 631 * own vnodes if they fail to implement VOP_PUTPAGES. 632 * 633 * This is typically called indirectly via the pageout daemon and 634 * clustering has already typically occured, so in general we ask the 635 * underlying filesystem to write the data out asynchronously rather 636 * then delayed. 637 */ 638 int 639 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 640 int flags, int *rtvals) 641 { 642 int i; 643 vm_object_t object; 644 int count; 645 646 int maxsize, ncount; 647 vm_ooffset_t poffset; 648 struct uio auio; 649 struct iovec aiov; 650 int error; 651 int ioflags; 652 653 object = vp->v_object; 654 count = bytecount / PAGE_SIZE; 655 656 for (i = 0; i < count; i++) 657 rtvals[i] = VM_PAGER_AGAIN; 658 659 if ((int) m[0]->pindex < 0) { 660 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 661 (long)m[0]->pindex, m[0]->dirty); 662 rtvals[0] = VM_PAGER_BAD; 663 return VM_PAGER_BAD; 664 } 665 666 maxsize = count * PAGE_SIZE; 667 ncount = count; 668 669 poffset = IDX_TO_OFF(m[0]->pindex); 670 671 /* 672 * If the page-aligned write is larger then the actual file we 673 * have to invalidate pages occuring beyond the file EOF. However, 674 * there is an edge case where a file may not be page-aligned where 675 * the last page is partially invalid. In this case the filesystem 676 * may not properly clear the dirty bits for the entire page (which 677 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 678 * With the page locked we are free to fix-up the dirty bits here. 679 * 680 * We do not under any circumstances truncate the valid bits, as 681 * this will screw up bogus page replacement. 682 * 683 * The caller has already read-protected the pages. The VFS must 684 * use the buffer cache to wrap the pages. The pages might not 685 * be immediately flushed by the buffer cache but once under its 686 * control the pages themselves can wind up being marked clean 687 * and their covering buffer cache buffer can be marked dirty. 688 */ 689 if (maxsize + poffset > vp->v_filesize) { 690 if (vp->v_filesize > poffset) { 691 int pgoff; 692 693 maxsize = vp->v_filesize - poffset; 694 ncount = btoc(maxsize); 695 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 696 vm_page_clear_dirty(m[ncount - 1], pgoff, 697 PAGE_SIZE - pgoff); 698 } 699 } else { 700 maxsize = 0; 701 ncount = 0; 702 } 703 if (ncount < count) { 704 for (i = ncount; i < count; i++) { 705 rtvals[i] = VM_PAGER_BAD; 706 } 707 } 708 } 709 710 /* 711 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 712 * rather then a bdwrite() to prevent paging I/O from saturating 713 * the buffer cache. Dummy-up the sequential heuristic to cause 714 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 715 * the system decides how to cluster. 716 */ 717 ioflags = IO_VMIO; 718 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 719 ioflags |= IO_SYNC; 720 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 721 ioflags |= IO_ASYNC; 722 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 723 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 724 725 aiov.iov_base = (caddr_t) 0; 726 aiov.iov_len = maxsize; 727 auio.uio_iov = &aiov; 728 auio.uio_iovcnt = 1; 729 auio.uio_offset = poffset; 730 auio.uio_segflg = UIO_NOCOPY; 731 auio.uio_rw = UIO_WRITE; 732 auio.uio_resid = maxsize; 733 auio.uio_td = NULL; 734 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 735 mycpu->gd_cnt.v_vnodeout++; 736 mycpu->gd_cnt.v_vnodepgsout += ncount; 737 738 if (error) { 739 krateprintf(&vbadrate, 740 "vnode_pager_putpages: I/O error %d\n", error); 741 } 742 if (auio.uio_resid) { 743 krateprintf(&vresrate, 744 "vnode_pager_putpages: residual I/O %d at %lu\n", 745 auio.uio_resid, (u_long)m[0]->pindex); 746 } 747 for (i = 0; i < ncount; i++) 748 rtvals[i] = VM_PAGER_OK; 749 return rtvals[0]; 750 } 751 752 struct vnode * 753 vnode_pager_lock(vm_object_t object) 754 { 755 struct thread *td = curthread; /* XXX */ 756 int error; 757 758 for (; object != NULL; object = object->backing_object) { 759 if (object->type != OBJT_VNODE) 760 continue; 761 if (object->flags & OBJ_DEAD) 762 return NULL; 763 764 for (;;) { 765 struct vnode *vp = object->handle; 766 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 767 if (error == 0) { 768 if (object->handle != vp) { 769 vput(vp); 770 continue; 771 } 772 return (vp); 773 } 774 if ((object->flags & OBJ_DEAD) || 775 (object->type != OBJT_VNODE)) { 776 return NULL; 777 } 778 kprintf("vnode_pager_lock: vp %p error %d lockstatus %d, retrying\n", vp, error, lockstatus(&vp->v_lock, td)); 779 tsleep(object->handle, 0, "vnpgrl", hz); 780 } 781 } 782 return NULL; 783 } 784