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