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 66 #include <vm/vm.h> 67 #include <vm/vm_object.h> 68 #include <vm/vm_page.h> 69 #include <vm/vm_pager.h> 70 #include <vm/vm_map.h> 71 #include <vm/vnode_pager.h> 72 #include <vm/vm_extern.h> 73 74 #include <sys/thread2.h> 75 #include <vm/vm_page2.h> 76 77 static void vnode_pager_dealloc (vm_object_t); 78 static int vnode_pager_getpages (vm_object_t, vm_page_t *, int, int); 79 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *); 80 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t, int *, int *); 81 82 struct pagerops vnodepagerops = { 83 NULL, 84 vnode_pager_alloc, 85 vnode_pager_dealloc, 86 vnode_pager_getpages, 87 vnode_pager_putpages, 88 vnode_pager_haspage, 89 NULL 90 }; 91 92 static struct krate vbadrate = { 1 }; 93 static struct krate vresrate = { 1 }; 94 95 int vnode_pbuf_freecnt = -1; /* start out unlimited */ 96 97 /* 98 * Allocate (or lookup) pager for a vnode. 99 * Handle is a vnode pointer. 100 */ 101 vm_object_t 102 vnode_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t offset) 103 { 104 vm_object_t object; 105 struct vnode *vp; 106 107 /* 108 * Pageout to vnode, no can do yet. 109 */ 110 if (handle == NULL) 111 return (NULL); 112 113 /* 114 * XXX hack - This initialization should be put somewhere else. 115 */ 116 if (vnode_pbuf_freecnt < 0) { 117 vnode_pbuf_freecnt = nswbuf / 2 + 1; 118 } 119 120 vp = (struct vnode *) handle; 121 122 /* 123 * Prevent race condition when allocating the object. This 124 * can happen with NFS vnodes since the nfsnode isn't locked. 125 */ 126 while (vp->v_flag & VOLOCK) { 127 vp->v_flag |= VOWANT; 128 tsleep(vp, 0, "vnpobj", 0); 129 } 130 vp->v_flag |= VOLOCK; 131 132 /* 133 * If the object is being terminated, wait for it to 134 * go away. 135 */ 136 while (((object = vp->v_object) != NULL) && 137 (object->flags & OBJ_DEAD)) { 138 vm_object_dead_sleep(object, "vadead"); 139 } 140 141 if (vp->v_sysref.refcnt <= 0) 142 panic("vnode_pager_alloc: no vnode reference"); 143 144 if (object == NULL) { 145 /* 146 * And an object of the appropriate size 147 */ 148 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); 149 object->flags = 0; 150 object->handle = handle; 151 vp->v_object = object; 152 vp->v_filesize = size; 153 } else { 154 object->ref_count++; 155 if (vp->v_filesize != size) { 156 kprintf("vnode_pager_alloc: Warning, filesize " 157 "mismatch %lld/%lld\n", 158 (long long)vp->v_filesize, 159 (long long)size); 160 } 161 } 162 vref(vp); 163 164 vp->v_flag &= ~VOLOCK; 165 if (vp->v_flag & VOWANT) { 166 vp->v_flag &= ~VOWANT; 167 wakeup(vp); 168 } 169 return (object); 170 } 171 172 static void 173 vnode_pager_dealloc(vm_object_t object) 174 { 175 struct vnode *vp = object->handle; 176 177 if (vp == NULL) 178 panic("vnode_pager_dealloc: pager already dealloced"); 179 180 vm_object_pip_wait(object, "vnpdea"); 181 182 object->handle = NULL; 183 object->type = OBJT_DEAD; 184 vp->v_object = NULL; 185 vp->v_filesize = NOOFFSET; 186 vp->v_flag &= ~(VTEXT | VOBJBUF); 187 } 188 189 /* 190 * Return whether the vnode pager has the requested page. Return the 191 * number of disk-contiguous pages before and after the requested page, 192 * not including the requested page. 193 */ 194 static boolean_t 195 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 196 int *after) 197 { 198 struct vnode *vp = object->handle; 199 off_t loffset; 200 off_t doffset; 201 int voff; 202 int bsize; 203 int error; 204 205 /* 206 * If no vp or vp is doomed or marked transparent to VM, we do not 207 * have the page. 208 */ 209 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 210 return FALSE; 211 212 /* 213 * If filesystem no longer mounted or offset beyond end of file we do 214 * not have the page. 215 */ 216 loffset = IDX_TO_OFF(pindex); 217 218 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 219 return FALSE; 220 221 bsize = vp->v_mount->mnt_stat.f_iosize; 222 voff = loffset % bsize; 223 224 /* 225 * BMAP returns byte counts before and after, where after 226 * is inclusive of the base page. haspage must return page 227 * counts before and after where after does not include the 228 * base page. 229 * 230 * BMAP is allowed to return a *after of 0 for backwards 231 * compatibility. The base page is still considered valid if 232 * no error is returned. 233 */ 234 error = VOP_BMAP(vp, loffset - voff, &doffset, after, before, 0); 235 if (error) { 236 if (before) 237 *before = 0; 238 if (after) 239 *after = 0; 240 return TRUE; 241 } 242 if (doffset == NOOFFSET) 243 return FALSE; 244 245 if (before) { 246 *before = (*before + voff) >> PAGE_SHIFT; 247 } 248 if (after) { 249 *after -= voff; 250 if (loffset + *after > vp->v_filesize) 251 *after = vp->v_filesize - loffset; 252 *after >>= PAGE_SHIFT; 253 if (*after < 0) 254 *after = 0; 255 } 256 return TRUE; 257 } 258 259 /* 260 * Lets the VM system know about a change in size for a file. 261 * We adjust our own internal size and flush any cached pages in 262 * the associated object that are affected by the size change. 263 * 264 * NOTE: This routine may be invoked as a result of a pager put 265 * operation (possibly at object termination time), so we must be careful. 266 * 267 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 268 * we do not blow up on the case. nsize will always be >= 0, however. 269 */ 270 void 271 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 272 { 273 vm_pindex_t nobjsize; 274 vm_pindex_t oobjsize; 275 vm_object_t object = vp->v_object; 276 277 if (object == NULL) 278 return; 279 280 /* 281 * Hasn't changed size 282 */ 283 if (nsize == vp->v_filesize) 284 return; 285 286 /* 287 * Has changed size. Adjust the VM object's size and v_filesize 288 * before we start scanning pages to prevent new pages from being 289 * allocated during the scan. 290 */ 291 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 292 oobjsize = object->size; 293 object->size = nobjsize; 294 295 /* 296 * File has shrunk. Toss any cached pages beyond the new EOF. 297 */ 298 if (nsize < vp->v_filesize) { 299 vp->v_filesize = nsize; 300 if (nobjsize < oobjsize) { 301 vm_object_page_remove(object, nobjsize, oobjsize, 302 FALSE); 303 } 304 /* 305 * This gets rid of garbage at the end of a page that is now 306 * only partially backed by the vnode. Since we are setting 307 * the entire page valid & clean after we are done we have 308 * to be sure that the portion of the page within the file 309 * bounds is already valid. If it isn't then making it 310 * valid would create a corrupt block. 311 */ 312 if (nsize & PAGE_MASK) { 313 vm_offset_t kva; 314 vm_page_t m; 315 316 do { 317 m = vm_page_lookup(object, OFF_TO_IDX(nsize)); 318 } while (m && vm_page_sleep_busy(m, TRUE, "vsetsz")); 319 320 if (m && m->valid) { 321 int base = (int)nsize & PAGE_MASK; 322 int size = PAGE_SIZE - base; 323 struct sf_buf *sf; 324 325 /* 326 * Clear out partial-page garbage in case 327 * the page has been mapped. 328 * 329 * This is byte aligned. 330 */ 331 vm_page_busy(m); 332 sf = sf_buf_alloc(m, SFB_CPUPRIVATE); 333 kva = sf_buf_kva(sf); 334 bzero((caddr_t)kva + base, size); 335 sf_buf_free(sf); 336 337 /* 338 * XXX work around SMP data integrity race 339 * by unmapping the page from user processes. 340 * The garbage we just cleared may be mapped 341 * to a user process running on another cpu 342 * and this code is not running through normal 343 * I/O channels which handle SMP issues for 344 * us, so unmap page to synchronize all cpus. 345 * 346 * XXX should vm_pager_unmap_page() have 347 * dealt with this? 348 */ 349 vm_page_protect(m, VM_PROT_NONE); 350 351 /* 352 * Clear out partial-page dirty bits. This 353 * has the side effect of setting the valid 354 * bits, but that is ok. There are a bunch 355 * of places in the VM system where we expected 356 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 357 * case is one of them. If the page is still 358 * partially dirty, make it fully dirty. 359 * 360 * NOTE: We do not clear out the valid 361 * bits. This would prevent bogus_page 362 * replacement from working properly. 363 * 364 * NOTE: We do not want to clear the dirty 365 * bit for a partial DEV_BSIZE'd truncation! 366 * This is DEV_BSIZE aligned! 367 */ 368 vm_page_clear_dirty_beg_nonincl(m, base, size); 369 if (m->dirty != 0) 370 m->dirty = VM_PAGE_BITS_ALL; 371 vm_page_wakeup(m); 372 } 373 } 374 } else { 375 vp->v_filesize = nsize; 376 } 377 } 378 379 /* 380 * Release a page busied for a getpages operation. The page may have become 381 * wired (typically due to being used by the buffer cache) or otherwise been 382 * soft-busied and cannot be freed in that case. A held page can still be 383 * freed. 384 */ 385 void 386 vnode_pager_freepage(vm_page_t m) 387 { 388 if (m->busy || m->wire_count) { 389 vm_page_activate(m); 390 vm_page_wakeup(m); 391 } else { 392 vm_page_free(m); 393 } 394 } 395 396 /* 397 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 398 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 399 * vnode_pager_generic_getpages() to implement the previous behaviour. 400 * 401 * All other FS's should use the bypass to get to the local media 402 * backing vp's VOP_GETPAGES. 403 */ 404 static int 405 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 406 { 407 int rtval; 408 struct vnode *vp; 409 int bytes = count * PAGE_SIZE; 410 411 vp = object->handle; 412 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 413 if (rtval == EOPNOTSUPP) 414 panic("vnode_pager: vfs's must implement vop_getpages\n"); 415 return rtval; 416 } 417 418 /* 419 * This is now called from local media FS's to operate against their 420 * own vnodes if they fail to implement VOP_GETPAGES. 421 * 422 * With all the caching local media devices do these days there is really 423 * very little point to attempting to restrict the I/O size to contiguous 424 * blocks on-disk, especially if our caller thinks we need all the specified 425 * pages. Just construct and issue a READ. 426 */ 427 int 428 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount, 429 int reqpage) 430 { 431 struct iovec aiov; 432 struct uio auio; 433 off_t foff; 434 int error; 435 int count; 436 int i; 437 int ioflags; 438 439 /* 440 * Do not do anything if the vnode is bad. 441 */ 442 if (vp->v_mount == NULL) 443 return VM_PAGER_BAD; 444 445 /* 446 * Calculate the number of pages. Since we are paging in whole 447 * pages, adjust bytecount to be an integral multiple of the page 448 * size. It will be clipped to the file EOF later on. 449 */ 450 bytecount = round_page(bytecount); 451 count = bytecount / PAGE_SIZE; 452 453 /* 454 * If we have a completely valid page available to us, we can 455 * clean up and return. Otherwise we have to re-read the 456 * media. 457 * 458 * Note that this does not work with NFS, so NFS has its own 459 * getpages routine. The problem is that NFS can have partially 460 * valid pages associated with the buffer cache due to the piecemeal 461 * write support. If we were to fall through and re-read the media 462 * as we do here, dirty data could be lost. 463 */ 464 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 465 for (i = 0; i < count; i++) { 466 if (i != reqpage) 467 vnode_pager_freepage(m[i]); 468 } 469 return VM_PAGER_OK; 470 } 471 472 /* 473 * Discard pages past the file EOF. If the requested page is past 474 * the file EOF we just leave its valid bits set to 0, the caller 475 * expects to maintain ownership of the requested page. If the 476 * entire range is past file EOF discard everything and generate 477 * a pagein error. 478 */ 479 foff = IDX_TO_OFF(m[0]->pindex); 480 if (foff >= vp->v_filesize) { 481 for (i = 0; i < count; i++) { 482 if (i != reqpage) 483 vnode_pager_freepage(m[i]); 484 } 485 return VM_PAGER_ERROR; 486 } 487 488 if (foff + bytecount > vp->v_filesize) { 489 bytecount = vp->v_filesize - foff; 490 i = round_page(bytecount) / PAGE_SIZE; 491 while (count > i) { 492 --count; 493 if (count != reqpage) 494 vnode_pager_freepage(m[count]); 495 } 496 } 497 498 /* 499 * The size of the transfer is bytecount. bytecount will be an 500 * integral multiple of the page size unless it has been clipped 501 * to the file EOF. The transfer cannot exceed the file EOF. 502 * 503 * When dealing with real devices we must round-up to the device 504 * sector size. 505 */ 506 if (vp->v_type == VBLK || vp->v_type == VCHR) { 507 int secmask = vp->v_rdev->si_bsize_phys - 1; 508 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 509 bytecount = (bytecount + secmask) & ~secmask; 510 } 511 512 /* 513 * Severe hack to avoid deadlocks with the buffer cache 514 */ 515 for (i = 0; i < count; ++i) { 516 vm_page_t mt = m[i]; 517 518 vm_page_io_start(mt); 519 vm_page_wakeup(mt); 520 } 521 522 /* 523 * Issue the I/O without any read-ahead 524 */ 525 ioflags = IO_VMIO; 526 /*ioflags |= IO_SEQMAX << IO_SEQSHIFT;*/ 527 528 aiov.iov_base = (caddr_t) 0; 529 aiov.iov_len = bytecount; 530 auio.uio_iov = &aiov; 531 auio.uio_iovcnt = 1; 532 auio.uio_offset = foff; 533 auio.uio_segflg = UIO_NOCOPY; 534 auio.uio_rw = UIO_READ; 535 auio.uio_resid = bytecount; 536 auio.uio_td = NULL; 537 mycpu->gd_cnt.v_vnodein++; 538 mycpu->gd_cnt.v_vnodepgsin += count; 539 540 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 541 542 /* 543 * Severe hack to avoid deadlocks with the buffer cache 544 */ 545 for (i = 0; i < count; ++i) { 546 vm_page_t mt = m[i]; 547 548 while (vm_page_sleep_busy(mt, FALSE, "getpgs")) 549 ; 550 vm_page_busy(mt); 551 vm_page_io_finish(mt); 552 } 553 554 /* 555 * Calculate the actual number of bytes read and clean up the 556 * page list. 557 */ 558 bytecount -= auio.uio_resid; 559 560 for (i = 0; i < count; ++i) { 561 vm_page_t mt = m[i]; 562 563 if (i != reqpage) { 564 if (error == 0 && mt->valid) { 565 if (mt->flags & PG_WANTED) 566 vm_page_activate(mt); 567 else 568 vm_page_deactivate(mt); 569 vm_page_wakeup(mt); 570 } else { 571 vnode_pager_freepage(mt); 572 } 573 } else if (mt->valid == 0) { 574 if (error == 0) { 575 kprintf("page failed but no I/O error page %p object %p pindex %d\n", mt, mt->object, (int) mt->pindex); 576 /* whoops, something happened */ 577 error = EINVAL; 578 } 579 } else if (mt->valid != VM_PAGE_BITS_ALL) { 580 /* 581 * Zero-extend the requested page if necessary (if 582 * the filesystem is using a small block size). 583 */ 584 vm_page_zero_invalid(mt, TRUE); 585 } 586 } 587 if (error) { 588 kprintf("vnode_pager_getpages: I/O read error\n"); 589 } 590 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 591 } 592 593 /* 594 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 595 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 596 * vnode_pager_generic_putpages() to implement the previous behaviour. 597 * 598 * Caller has already cleared the pmap modified bits, if any. 599 * 600 * All other FS's should use the bypass to get to the local media 601 * backing vp's VOP_PUTPAGES. 602 */ 603 static void 604 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 605 boolean_t sync, int *rtvals) 606 { 607 int rtval; 608 struct vnode *vp; 609 int bytes = count * PAGE_SIZE; 610 611 /* 612 * Force synchronous operation if we are extremely low on memory 613 * to prevent a low-memory deadlock. VOP operations often need to 614 * allocate more memory to initiate the I/O ( i.e. do a BMAP 615 * operation ). The swapper handles the case by limiting the amount 616 * of asynchronous I/O, but that sort of solution doesn't scale well 617 * for the vnode pager without a lot of work. 618 * 619 * Also, the backing vnode's iodone routine may not wake the pageout 620 * daemon up. This should be probably be addressed XXX. 621 */ 622 623 if ((vmstats.v_free_count + vmstats.v_cache_count) < vmstats.v_pageout_free_min) 624 sync |= OBJPC_SYNC; 625 626 /* 627 * Call device-specific putpages function 628 */ 629 vp = object->handle; 630 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 631 if (rtval == EOPNOTSUPP) { 632 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 633 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 634 } 635 } 636 637 638 /* 639 * This is now called from local media FS's to operate against their 640 * own vnodes if they fail to implement VOP_PUTPAGES. 641 * 642 * This is typically called indirectly via the pageout daemon and 643 * clustering has already typically occured, so in general we ask the 644 * underlying filesystem to write the data out asynchronously rather 645 * then delayed. 646 */ 647 int 648 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 649 int flags, int *rtvals) 650 { 651 int i; 652 vm_object_t object; 653 int maxsize, ncount, count; 654 vm_ooffset_t poffset; 655 struct uio auio; 656 struct iovec aiov; 657 int error; 658 int ioflags; 659 660 object = vp->v_object; 661 count = bytecount / PAGE_SIZE; 662 663 for (i = 0; i < count; i++) 664 rtvals[i] = VM_PAGER_AGAIN; 665 666 if ((int) m[0]->pindex < 0) { 667 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 668 (long)m[0]->pindex, m[0]->dirty); 669 rtvals[0] = VM_PAGER_BAD; 670 return VM_PAGER_BAD; 671 } 672 673 maxsize = count * PAGE_SIZE; 674 ncount = count; 675 676 poffset = IDX_TO_OFF(m[0]->pindex); 677 678 /* 679 * If the page-aligned write is larger then the actual file we 680 * have to invalidate pages occuring beyond the file EOF. 681 * 682 * If the file EOF resides in the middle of a page we still clear 683 * all of that page's dirty bits later on. If we didn't it would 684 * endlessly re-write. 685 * 686 * We do not under any circumstances truncate the valid bits, as 687 * this will screw up bogus page replacement. 688 * 689 * The caller has already read-protected the pages. The VFS must 690 * use the buffer cache to wrap the pages. The pages might not 691 * be immediately flushed by the buffer cache but once under its 692 * control the pages themselves can wind up being marked clean 693 * and their covering buffer cache buffer can be marked dirty. 694 */ 695 if (poffset + maxsize > vp->v_filesize) { 696 if (poffset < vp->v_filesize) { 697 maxsize = vp->v_filesize - poffset; 698 ncount = btoc(maxsize); 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 %zd at %lu\n", 745 auio.uio_resid, (u_long)m[0]->pindex); 746 } 747 if (error == 0) { 748 for (i = 0; i < ncount; i++) { 749 rtvals[i] = VM_PAGER_OK; 750 vm_page_undirty(m[i]); 751 } 752 } 753 return rtvals[0]; 754 } 755 756 struct vnode * 757 vnode_pager_lock(vm_object_t object) 758 { 759 struct thread *td = curthread; /* XXX */ 760 int error; 761 762 for (; object != NULL; object = object->backing_object) { 763 if (object->type != OBJT_VNODE) 764 continue; 765 if (object->flags & OBJ_DEAD) 766 return NULL; 767 768 for (;;) { 769 struct vnode *vp = object->handle; 770 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 771 if (error == 0) { 772 if (object->handle != vp) { 773 vput(vp); 774 continue; 775 } 776 return (vp); 777 } 778 if ((object->flags & OBJ_DEAD) || 779 (object->type != OBJT_VNODE)) { 780 return NULL; 781 } 782 kprintf("vnode_pager_lock: vp %p error %d lockstatus %d, retrying\n", vp, error, lockstatus(&vp->v_lock, td)); 783 tsleep(object->handle, 0, "vnpgrl", hz); 784 } 785 } 786 return NULL; 787 } 788