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