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 1.40 2007/08/28 01:09:07 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 error = VOP_BMAP(vp, loffset - voff, &doffset, after, before); 219 if (error) 220 return TRUE; 221 if (doffset == NOOFFSET) 222 return FALSE; 223 224 if (before) { 225 *before = (*before + voff) >> PAGE_SHIFT; 226 } 227 if (after) { 228 *after -= voff; 229 if (loffset + *after > vp->v_filesize) 230 *after = vp->v_filesize - loffset; 231 *after >>= PAGE_SHIFT; 232 if (*after < 0) 233 *after = 0; 234 } 235 return TRUE; 236 } 237 238 /* 239 * Lets the VM system know about a change in size for a file. 240 * We adjust our own internal size and flush any cached pages in 241 * the associated object that are affected by the size change. 242 * 243 * NOTE: This routine may be invoked as a result of a pager put 244 * operation (possibly at object termination time), so we must be careful. 245 * 246 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 247 * we do not blow up on the case. nsize will always be >= 0, however. 248 */ 249 void 250 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 251 { 252 vm_pindex_t nobjsize; 253 vm_pindex_t oobjsize; 254 vm_object_t object = vp->v_object; 255 256 if (object == NULL) 257 return; 258 259 /* 260 * Hasn't changed size 261 */ 262 if (nsize == vp->v_filesize) 263 return; 264 265 /* 266 * Has changed size. Adjust the VM object's size and v_filesize 267 * before we start scanning pages to prevent new pages from being 268 * allocated during the scan. 269 */ 270 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 271 oobjsize = object->size; 272 object->size = nobjsize; 273 274 /* 275 * File has shrunk. Toss any cached pages beyond the new EOF. 276 */ 277 if (nsize < vp->v_filesize) { 278 vp->v_filesize = nsize; 279 if (nobjsize < oobjsize) { 280 vm_object_page_remove(object, nobjsize, oobjsize, 281 FALSE); 282 } 283 /* 284 * This gets rid of garbage at the end of a page that is now 285 * only partially backed by the vnode. Since we are setting 286 * the entire page valid & clean after we are done we have 287 * to be sure that the portion of the page within the file 288 * bounds is already valid. If it isn't then making it 289 * valid would create a corrupt block. 290 */ 291 if (nsize & PAGE_MASK) { 292 vm_offset_t kva; 293 vm_page_t m; 294 295 m = vm_page_lookup(object, OFF_TO_IDX(nsize)); 296 if (m && m->valid) { 297 int base = (int)nsize & PAGE_MASK; 298 int size = PAGE_SIZE - base; 299 struct sf_buf *sf; 300 301 /* 302 * Clear out partial-page garbage in case 303 * the page has been mapped. 304 */ 305 sf = sf_buf_alloc(m, SFB_CPUPRIVATE); 306 kva = sf_buf_kva(sf); 307 bzero((caddr_t)kva + base, size); 308 sf_buf_free(sf); 309 310 /* 311 * XXX work around SMP data integrity race 312 * by unmapping the page from user processes. 313 * The garbage we just cleared may be mapped 314 * to a user process running on another cpu 315 * and this code is not running through normal 316 * I/O channels which handle SMP issues for 317 * us, so unmap page to synchronize all cpus. 318 * 319 * XXX should vm_pager_unmap_page() have 320 * dealt with this? 321 */ 322 vm_page_protect(m, VM_PROT_NONE); 323 324 /* 325 * Clear out partial-page dirty bits. This 326 * has the side effect of setting the valid 327 * bits, but that is ok. There are a bunch 328 * of places in the VM system where we expected 329 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 330 * case is one of them. If the page is still 331 * partially dirty, make it fully dirty. 332 * 333 * note that we do not clear out the valid 334 * bits. This would prevent bogus_page 335 * replacement from working properly. 336 */ 337 vm_page_set_validclean(m, base, size); 338 if (m->dirty != 0) 339 m->dirty = VM_PAGE_BITS_ALL; 340 } 341 } 342 } else { 343 vp->v_filesize = nsize; 344 } 345 } 346 347 /* 348 * Release a page busied for a getpages operation. The page may have become 349 * wired (typically due to being used by the buffer cache) or otherwise been 350 * soft-busied and cannot be freed in that case. A held page can still be 351 * freed. 352 */ 353 void 354 vnode_pager_freepage(vm_page_t m) 355 { 356 if (m->busy || m->wire_count) { 357 vm_page_activate(m); 358 vm_page_wakeup(m); 359 } else { 360 vm_page_free(m); 361 } 362 } 363 364 /* 365 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 366 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 367 * vnode_pager_generic_getpages() to implement the previous behaviour. 368 * 369 * All other FS's should use the bypass to get to the local media 370 * backing vp's VOP_GETPAGES. 371 */ 372 static int 373 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 374 { 375 int rtval; 376 struct vnode *vp; 377 int bytes = count * PAGE_SIZE; 378 379 vp = object->handle; 380 rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); 381 if (rtval == EOPNOTSUPP) 382 panic("vnode_pager: vfs's must implement vop_getpages\n"); 383 return rtval; 384 } 385 386 /* 387 * This is now called from local media FS's to operate against their 388 * own vnodes if they fail to implement VOP_GETPAGES. 389 * 390 * With all the caching local media devices do these days there is really 391 * very little point to attempting to restrict the I/O size to contiguous 392 * blocks on-disk, especially if our caller thinks we need all the specified 393 * pages. Just construct and issue a READ. 394 */ 395 int 396 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount, 397 int reqpage) 398 { 399 struct iovec aiov; 400 struct uio auio; 401 off_t foff; 402 int error; 403 int count; 404 int i; 405 int ioflags; 406 407 /* 408 * Do not do anything if the vnode is bad. 409 */ 410 if (vp->v_mount == NULL) 411 return VM_PAGER_BAD; 412 413 /* 414 * Calculate the number of pages. Since we are paging in whole 415 * pages, adjust bytecount to be an integral multiple of the page 416 * size. It will be clipped to the file EOF later on. 417 */ 418 bytecount = round_page(bytecount); 419 count = bytecount / PAGE_SIZE; 420 421 /* 422 * If we have a completely valid page available to us, we can 423 * clean up and return. Otherwise we have to re-read the 424 * media. 425 * 426 * Note that this does not work with NFS, so NFS has its own 427 * getpages routine. The problem is that NFS can have partially 428 * valid pages associated with the buffer cache due to the piecemeal 429 * write support. If we were to fall through and re-read the media 430 * as we do here, dirty data could be lost. 431 */ 432 if (m[reqpage]->valid == VM_PAGE_BITS_ALL) { 433 for (i = 0; i < count; i++) { 434 if (i != reqpage) 435 vnode_pager_freepage(m[i]); 436 } 437 return VM_PAGER_OK; 438 } 439 440 /* 441 * Discard pages past the file EOF. If the requested page is past 442 * the file EOF we just leave its valid bits set to 0, the caller 443 * expects to maintain ownership of the requested page. If the 444 * entire range is past file EOF discard everything and generate 445 * a pagein error. 446 */ 447 foff = IDX_TO_OFF(m[0]->pindex); 448 if (foff >= vp->v_filesize) { 449 for (i = 0; i < count; i++) { 450 if (i != reqpage) 451 vnode_pager_freepage(m[i]); 452 } 453 return VM_PAGER_ERROR; 454 } 455 456 if (foff + bytecount > vp->v_filesize) { 457 bytecount = vp->v_filesize - foff; 458 i = round_page(bytecount) / PAGE_SIZE; 459 while (count > i) { 460 --count; 461 if (count != reqpage) 462 vnode_pager_freepage(m[count]); 463 } 464 } 465 466 /* 467 * The size of the transfer is bytecount. bytecount will be an 468 * integral multiple of the page size unless it has been clipped 469 * to the file EOF. The transfer cannot exceed the file EOF. 470 * 471 * When dealing with real devices we must round-up to the device 472 * sector size. 473 */ 474 if (vp->v_type == VBLK || vp->v_type == VCHR) { 475 int secmask = vp->v_rdev->si_bsize_phys - 1; 476 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 477 bytecount = (bytecount + secmask) & ~secmask; 478 } 479 480 /* 481 * Severe hack to avoid deadlocks with the buffer cache 482 */ 483 for (i = 0; i < count; ++i) { 484 vm_page_t mt = m[i]; 485 486 vm_page_io_start(mt); 487 vm_page_wakeup(mt); 488 } 489 490 /* 491 * Issue the I/O without any read-ahead 492 */ 493 ioflags = IO_VMIO; 494 /*ioflags |= IO_SEQMAX << IO_SEQSHIFT;*/ 495 496 aiov.iov_base = (caddr_t) 0; 497 aiov.iov_len = bytecount; 498 auio.uio_iov = &aiov; 499 auio.uio_iovcnt = 1; 500 auio.uio_offset = foff; 501 auio.uio_segflg = UIO_NOCOPY; 502 auio.uio_rw = UIO_READ; 503 auio.uio_resid = bytecount; 504 auio.uio_td = NULL; 505 mycpu->gd_cnt.v_vnodein++; 506 mycpu->gd_cnt.v_vnodepgsin += count; 507 508 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 509 510 /* 511 * Severe hack to avoid deadlocks with the buffer cache 512 */ 513 for (i = 0; i < count; ++i) { 514 vm_page_t mt = m[i]; 515 516 while (vm_page_sleep_busy(mt, FALSE, "getpgs")) 517 ; 518 vm_page_busy(mt); 519 vm_page_io_finish(mt); 520 } 521 522 /* 523 * Calculate the actual number of bytes read and clean up the 524 * page list. 525 */ 526 bytecount -= auio.uio_resid; 527 528 for (i = 0; i < count; ++i) { 529 vm_page_t mt = m[i]; 530 531 if (i != reqpage) { 532 if (error == 0 && mt->valid) { 533 if (mt->flags & PG_WANTED) 534 vm_page_activate(mt); 535 else 536 vm_page_deactivate(mt); 537 vm_page_wakeup(mt); 538 } else { 539 vnode_pager_freepage(mt); 540 } 541 } else if (mt->valid == 0) { 542 if (error == 0) { 543 kprintf("page failed but no I/O error page %p object %p pindex %d\n", mt, mt->object, (int) mt->pindex); 544 /* whoops, something happened */ 545 error = EINVAL; 546 } 547 } else if (mt->valid != VM_PAGE_BITS_ALL) { 548 /* 549 * Zero-extend the requested page if necessary (if 550 * the filesystem is using a small block size). 551 */ 552 vm_page_zero_invalid(mt, TRUE); 553 } 554 } 555 if (error) { 556 kprintf("vnode_pager_getpages: I/O read error\n"); 557 } 558 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 559 } 560 561 /* 562 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 563 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 564 * vnode_pager_generic_putpages() to implement the previous behaviour. 565 * 566 * All other FS's should use the bypass to get to the local media 567 * backing vp's VOP_PUTPAGES. 568 */ 569 static void 570 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 571 boolean_t sync, int *rtvals) 572 { 573 int rtval; 574 struct vnode *vp; 575 int bytes = count * PAGE_SIZE; 576 577 /* 578 * Force synchronous operation if we are extremely low on memory 579 * to prevent a low-memory deadlock. VOP operations often need to 580 * allocate more memory to initiate the I/O ( i.e. do a BMAP 581 * operation ). The swapper handles the case by limiting the amount 582 * of asynchronous I/O, but that sort of solution doesn't scale well 583 * for the vnode pager without a lot of work. 584 * 585 * Also, the backing vnode's iodone routine may not wake the pageout 586 * daemon up. This should be probably be addressed XXX. 587 */ 588 589 if ((vmstats.v_free_count + vmstats.v_cache_count) < vmstats.v_pageout_free_min) 590 sync |= OBJPC_SYNC; 591 592 /* 593 * Call device-specific putpages function 594 */ 595 596 vp = object->handle; 597 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 598 if (rtval == EOPNOTSUPP) { 599 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 600 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 601 } 602 } 603 604 605 /* 606 * This is now called from local media FS's to operate against their 607 * own vnodes if they fail to implement VOP_PUTPAGES. 608 * 609 * This is typically called indirectly via the pageout daemon and 610 * clustering has already typically occured, so in general we ask the 611 * underlying filesystem to write the data out asynchronously rather 612 * then delayed. 613 */ 614 int 615 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 616 int flags, int *rtvals) 617 { 618 int i; 619 vm_object_t object; 620 int count; 621 622 int maxsize, ncount; 623 vm_ooffset_t poffset; 624 struct uio auio; 625 struct iovec aiov; 626 int error; 627 int ioflags; 628 629 object = vp->v_object; 630 count = bytecount / PAGE_SIZE; 631 632 for (i = 0; i < count; i++) 633 rtvals[i] = VM_PAGER_AGAIN; 634 635 if ((int) m[0]->pindex < 0) { 636 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 637 (long)m[0]->pindex, m[0]->dirty); 638 rtvals[0] = VM_PAGER_BAD; 639 return VM_PAGER_BAD; 640 } 641 642 maxsize = count * PAGE_SIZE; 643 ncount = count; 644 645 poffset = IDX_TO_OFF(m[0]->pindex); 646 647 /* 648 * If the page-aligned write is larger then the actual file we 649 * have to invalidate pages occuring beyond the file EOF. However, 650 * there is an edge case where a file may not be page-aligned where 651 * the last page is partially invalid. In this case the filesystem 652 * may not properly clear the dirty bits for the entire page (which 653 * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). 654 * With the page locked we are free to fix-up the dirty bits here. 655 * 656 * We do not under any circumstances truncate the valid bits, as 657 * this will screw up bogus page replacement. 658 */ 659 if (maxsize + poffset > vp->v_filesize) { 660 if (vp->v_filesize > poffset) { 661 int pgoff; 662 663 maxsize = vp->v_filesize - poffset; 664 ncount = btoc(maxsize); 665 if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { 666 vm_page_clear_dirty(m[ncount - 1], pgoff, 667 PAGE_SIZE - pgoff); 668 } 669 } else { 670 maxsize = 0; 671 ncount = 0; 672 } 673 if (ncount < count) { 674 for (i = ncount; i < count; i++) { 675 rtvals[i] = VM_PAGER_BAD; 676 } 677 } 678 } 679 680 /* 681 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 682 * rather then a bdwrite() to prevent paging I/O from saturating 683 * the buffer cache. Dummy-up the sequential heuristic to cause 684 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 685 * the system decides how to cluster. 686 */ 687 ioflags = IO_VMIO; 688 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 689 ioflags |= IO_SYNC; 690 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 691 ioflags |= IO_ASYNC; 692 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 693 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 694 695 aiov.iov_base = (caddr_t) 0; 696 aiov.iov_len = maxsize; 697 auio.uio_iov = &aiov; 698 auio.uio_iovcnt = 1; 699 auio.uio_offset = poffset; 700 auio.uio_segflg = UIO_NOCOPY; 701 auio.uio_rw = UIO_WRITE; 702 auio.uio_resid = maxsize; 703 auio.uio_td = NULL; 704 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 705 mycpu->gd_cnt.v_vnodeout++; 706 mycpu->gd_cnt.v_vnodepgsout += ncount; 707 708 if (error) { 709 krateprintf(&vbadrate, 710 "vnode_pager_putpages: I/O error %d\n", error); 711 } 712 if (auio.uio_resid) { 713 krateprintf(&vresrate, 714 "vnode_pager_putpages: residual I/O %d at %lu\n", 715 auio.uio_resid, (u_long)m[0]->pindex); 716 } 717 for (i = 0; i < ncount; i++) 718 rtvals[i] = VM_PAGER_OK; 719 return rtvals[0]; 720 } 721 722 struct vnode * 723 vnode_pager_lock(vm_object_t object) 724 { 725 struct thread *td = curthread; /* XXX */ 726 int error; 727 728 for (; object != NULL; object = object->backing_object) { 729 if (object->type != OBJT_VNODE) 730 continue; 731 if (object->flags & OBJ_DEAD) 732 return NULL; 733 734 for (;;) { 735 struct vnode *vp = object->handle; 736 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 737 if (error == 0) { 738 if (object->handle != vp) { 739 vput(vp); 740 continue; 741 } 742 return (vp); 743 } 744 if ((object->flags & OBJ_DEAD) || 745 (object->type != OBJT_VNODE)) { 746 return NULL; 747 } 748 kprintf("vnode_pager_lock: vp %p error %d lockstatus %d, retrying\n", vp, error, lockstatus(&vp->v_lock, td)); 749 tsleep(object->handle, 0, "vnpgrl", hz); 750 } 751 } 752 return NULL; 753 } 754