1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1990 University of Utah. 5 * Copyright (c) 1991 The Regents of the University of California. 6 * All rights reserved. 7 * Copyright (c) 1993, 1994 John S. Dyson 8 * Copyright (c) 1995, David Greenman 9 * 10 * This code is derived from software contributed to Berkeley by 11 * the Systems Programming Group of the University of Utah Computer 12 * Science Department. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 39 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $ 40 */ 41 42 /* 43 * Page to/from files (vnodes). 44 */ 45 46 /* 47 * TODO: 48 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 49 * greatly re-simplify the vnode_pager. 50 */ 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/kernel.h> 55 #include <sys/proc.h> 56 #include <sys/vnode.h> 57 #include <sys/mount.h> 58 #include <sys/buf.h> 59 #include <sys/vmmeter.h> 60 #include <sys/conf.h> 61 62 #include <cpu/lwbuf.h> 63 64 #include <vm/vm.h> 65 #include <vm/vm_object.h> 66 #include <vm/vm_page.h> 67 #include <vm/vm_pager.h> 68 #include <vm/vm_map.h> 69 #include <vm/vnode_pager.h> 70 #include <vm/swap_pager.h> 71 #include <vm/vm_extern.h> 72 73 #include <sys/thread2.h> 74 #include <vm/vm_page2.h> 75 76 static void vnode_pager_dealloc (vm_object_t); 77 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int); 78 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *); 79 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t); 80 81 struct pagerops vnodepagerops = { 82 vnode_pager_dealloc, 83 vnode_pager_getpage, 84 vnode_pager_putpages, 85 vnode_pager_haspage 86 }; 87 88 static struct krate vbadrate = { 1 }; 89 static struct krate vresrate = { 1 }; 90 91 long vnode_pbuf_freecnt = -1; /* start out unlimited */ 92 93 /* 94 * Allocate a VM object for a vnode, typically a regular file vnode. 95 * 96 * Some additional information is required to generate a properly sized 97 * object which covers the entire buffer cache buffer straddling the file 98 * EOF. Userland does not see the extra pages as the VM fault code tests 99 * against v_filesize. 100 */ 101 vm_object_t 102 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset, 103 int blksize, int boff) 104 { 105 vm_object_t object; 106 struct vnode *vp; 107 off_t loffset; 108 vm_pindex_t lsize; 109 110 /* 111 * Pageout to vnode, no can do yet. 112 */ 113 if (handle == NULL) 114 return (NULL); 115 116 /* 117 * XXX hack - This initialization should be put somewhere else. 118 */ 119 if (vnode_pbuf_freecnt < 0) { 120 vnode_pbuf_freecnt = nswbuf / 2 + 1; 121 } 122 123 /* 124 * Serialize potential vnode/object teardowns and interlocks 125 */ 126 vp = (struct vnode *)handle; 127 lwkt_gettoken(&vp->v_token); 128 129 /* 130 * Prevent race condition when allocating the object. This 131 * can happen with NFS vnodes since the nfsnode isn't locked. 132 */ 133 while (vp->v_flag & VOLOCK) { 134 vsetflags(vp, VOWANT); 135 tsleep(vp, 0, "vnpobj", 0); 136 } 137 vsetflags(vp, VOLOCK); 138 lwkt_reltoken(&vp->v_token); 139 140 /* 141 * If the object is being terminated, wait for it to 142 * go away. 143 */ 144 while ((object = vp->v_object) != NULL) { 145 vm_object_hold(object); 146 if ((object->flags & OBJ_DEAD) == 0) 147 break; 148 vm_object_dead_sleep(object, "vadead"); 149 vm_object_drop(object); 150 } 151 152 if (vp->v_sysref.refcnt <= 0) 153 panic("vnode_pager_alloc: no vnode reference"); 154 155 /* 156 * Round up to the *next* block, then destroy the buffers in question. 157 * Since we are only removing some of the buffers we must rely on the 158 * scan count to determine whether a loop is necessary. 159 * 160 * Destroy any pages beyond the last buffer. 161 */ 162 if (boff < 0) 163 boff = (int)(length % blksize); 164 if (boff) 165 loffset = length + (blksize - boff); 166 else 167 loffset = length; 168 lsize = OFF_TO_IDX(round_page64(loffset)); 169 170 if (object == NULL) { 171 /* 172 * And an object of the appropriate size 173 */ 174 object = vm_object_allocate_hold(OBJT_VNODE, lsize); 175 object->handle = handle; 176 vp->v_object = object; 177 vp->v_filesize = length; 178 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC)) 179 vm_object_set_flag(object, OBJ_NOMSYNC); 180 } else { 181 object->ref_count++; 182 if (object->size != lsize) { 183 kprintf("vnode_pager_alloc: Warning, objsize " 184 "mismatch %jd/%jd vp=%p obj=%p\n", 185 (intmax_t)object->size, 186 (intmax_t)lsize, 187 vp, object); 188 } 189 if (vp->v_filesize != length) { 190 kprintf("vnode_pager_alloc: Warning, filesize " 191 "mismatch %jd/%jd vp=%p obj=%p\n", 192 (intmax_t)vp->v_filesize, 193 (intmax_t)length, 194 vp, object); 195 } 196 } 197 198 vref(vp); 199 lwkt_gettoken(&vp->v_token); 200 vclrflags(vp, VOLOCK); 201 if (vp->v_flag & VOWANT) { 202 vclrflags(vp, VOWANT); 203 wakeup(vp); 204 } 205 lwkt_reltoken(&vp->v_token); 206 207 vm_object_drop(object); 208 209 return (object); 210 } 211 212 /* 213 * Add a ref to a vnode's existing VM object, return the object or 214 * NULL if the vnode did not have one. This does not create the 215 * object (we can't since we don't know what the proper blocksize/boff 216 * is to match the VFS's use of the buffer cache). 217 */ 218 vm_object_t 219 vnode_pager_reference(struct vnode *vp) 220 { 221 vm_object_t object; 222 223 /* 224 * Prevent race condition when allocating the object. This 225 * can happen with NFS vnodes since the nfsnode isn't locked. 226 * 227 * Serialize potential vnode/object teardowns and interlocks 228 */ 229 lwkt_gettoken(&vp->v_token); 230 while (vp->v_flag & VOLOCK) { 231 vsetflags(vp, VOWANT); 232 tsleep(vp, 0, "vnpobj", 0); 233 } 234 vsetflags(vp, VOLOCK); 235 lwkt_reltoken(&vp->v_token); 236 237 /* 238 * Prevent race conditions against deallocation of the VM 239 * object. 240 */ 241 while ((object = vp->v_object) != NULL) { 242 vm_object_hold(object); 243 if ((object->flags & OBJ_DEAD) == 0) 244 break; 245 vm_object_dead_sleep(object, "vadead"); 246 vm_object_drop(object); 247 } 248 249 /* 250 * The object is expected to exist, the caller will handle 251 * NULL returns if it does not. 252 */ 253 if (object) { 254 object->ref_count++; 255 vref(vp); 256 } 257 258 lwkt_gettoken(&vp->v_token); 259 vclrflags(vp, VOLOCK); 260 if (vp->v_flag & VOWANT) { 261 vclrflags(vp, VOWANT); 262 wakeup(vp); 263 } 264 lwkt_reltoken(&vp->v_token); 265 if (object) 266 vm_object_drop(object); 267 268 return (object); 269 } 270 271 static void 272 vnode_pager_dealloc(vm_object_t object) 273 { 274 struct vnode *vp = object->handle; 275 276 if (vp == NULL) 277 panic("vnode_pager_dealloc: pager already dealloced"); 278 279 vm_object_pip_wait(object, "vnpdea"); 280 281 object->handle = NULL; 282 object->type = OBJT_DEAD; 283 vp->v_object = NULL; 284 vp->v_filesize = NOOFFSET; 285 vclrflags(vp, VTEXT | VOBJBUF); 286 swap_pager_freespace_all(object); 287 } 288 289 /* 290 * Return whether the vnode pager has the requested page. Return the 291 * number of disk-contiguous pages before and after the requested page, 292 * not including the requested page. 293 */ 294 static boolean_t 295 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex) 296 { 297 struct vnode *vp = object->handle; 298 off_t loffset; 299 off_t doffset; 300 int voff; 301 int bsize; 302 int error; 303 304 /* 305 * If no vp or vp is doomed or marked transparent to VM, we do not 306 * have the page. 307 */ 308 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 309 return FALSE; 310 311 /* 312 * If filesystem no longer mounted or offset beyond end of file we do 313 * not have the page. 314 */ 315 loffset = IDX_TO_OFF(pindex); 316 317 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 318 return FALSE; 319 320 bsize = vp->v_mount->mnt_stat.f_iosize; 321 voff = loffset % bsize; 322 323 /* 324 * XXX 325 * 326 * BMAP returns byte counts before and after, where after 327 * is inclusive of the base page. haspage must return page 328 * counts before and after where after does not include the 329 * base page. 330 * 331 * BMAP is allowed to return a *after of 0 for backwards 332 * compatibility. The base page is still considered valid if 333 * no error is returned. 334 */ 335 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0); 336 if (error) 337 return TRUE; 338 if (doffset == NOOFFSET) 339 return FALSE; 340 return TRUE; 341 } 342 343 /* 344 * Lets the VM system know about a change in size for a file. 345 * We adjust our own internal size and flush any cached pages in 346 * the associated object that are affected by the size change. 347 * 348 * NOTE: This routine may be invoked as a result of a pager put 349 * operation (possibly at object termination time), so we must be careful. 350 * 351 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 352 * we do not blow up on the case. nsize will always be >= 0, however. 353 */ 354 void 355 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 356 { 357 vm_pindex_t nobjsize; 358 vm_pindex_t oobjsize; 359 vm_object_t object; 360 361 while ((object = vp->v_object) != NULL) { 362 vm_object_hold(object); 363 if (vp->v_object == object) 364 break; 365 vm_object_drop(object); 366 } 367 if (object == NULL) 368 return; 369 370 /* 371 * Hasn't changed size 372 */ 373 if (nsize == vp->v_filesize) { 374 vm_object_drop(object); 375 return; 376 } 377 378 /* 379 * Has changed size. Adjust the VM object's size and v_filesize 380 * before we start scanning pages to prevent new pages from being 381 * allocated during the scan. 382 */ 383 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 384 oobjsize = object->size; 385 object->size = nobjsize; 386 387 /* 388 * File has shrunk. Toss any cached pages beyond the new EOF. 389 */ 390 if (nsize < vp->v_filesize) { 391 vp->v_filesize = nsize; 392 if (nobjsize < oobjsize) { 393 vm_object_page_remove(object, nobjsize, oobjsize, 394 FALSE); 395 } 396 /* 397 * This gets rid of garbage at the end of a page that is now 398 * only partially backed by the vnode. Since we are setting 399 * the entire page valid & clean after we are done we have 400 * to be sure that the portion of the page within the file 401 * bounds is already valid. If it isn't then making it 402 * valid would create a corrupt block. 403 */ 404 if (nsize & PAGE_MASK) { 405 vm_offset_t kva; 406 vm_page_t m; 407 408 m = vm_page_lookup_busy_wait(object, OFF_TO_IDX(nsize), 409 TRUE, "vsetsz"); 410 411 if (m && m->valid) { 412 int base = (int)nsize & PAGE_MASK; 413 int size = PAGE_SIZE - base; 414 struct lwbuf *lwb; 415 struct lwbuf lwb_cache; 416 417 /* 418 * Clear out partial-page garbage in case 419 * the page has been mapped. 420 * 421 * This is byte aligned. 422 */ 423 lwb = lwbuf_alloc(m, &lwb_cache); 424 kva = lwbuf_kva(lwb); 425 bzero((caddr_t)kva + base, size); 426 lwbuf_free(lwb); 427 428 /* 429 * XXX work around SMP data integrity race 430 * by unmapping the page from user processes. 431 * The garbage we just cleared may be mapped 432 * to a user process running on another cpu 433 * and this code is not running through normal 434 * I/O channels which handle SMP issues for 435 * us, so unmap page to synchronize all cpus. 436 * 437 * XXX should vm_pager_unmap_page() have 438 * dealt with this? 439 */ 440 vm_page_protect(m, VM_PROT_NONE); 441 442 /* 443 * Clear out partial-page dirty bits. This 444 * has the side effect of setting the valid 445 * bits, but that is ok. There are a bunch 446 * of places in the VM system where we expected 447 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 448 * case is one of them. If the page is still 449 * partially dirty, make it fully dirty. 450 * 451 * NOTE: We do not clear out the valid 452 * bits. This would prevent bogus_page 453 * replacement from working properly. 454 * 455 * NOTE: We do not want to clear the dirty 456 * bit for a partial DEV_BSIZE'd truncation! 457 * This is DEV_BSIZE aligned! 458 */ 459 vm_page_clear_dirty_beg_nonincl(m, base, size); 460 if (m->dirty != 0) 461 m->dirty = VM_PAGE_BITS_ALL; 462 vm_page_wakeup(m); 463 } else if (m) { 464 vm_page_wakeup(m); 465 } 466 } 467 } else { 468 vp->v_filesize = nsize; 469 } 470 vm_object_drop(object); 471 } 472 473 /* 474 * Release a page busied for a getpages operation. The page may have become 475 * wired (typically due to being used by the buffer cache) or otherwise been 476 * soft-busied and cannot be freed in that case. A held page can still be 477 * freed. 478 */ 479 void 480 vnode_pager_freepage(vm_page_t m) 481 { 482 if (m->busy || m->wire_count || (m->flags & PG_NEED_COMMIT)) { 483 vm_page_activate(m); 484 vm_page_wakeup(m); 485 } else { 486 vm_page_free(m); 487 } 488 } 489 490 /* 491 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 492 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 493 * vnode_pager_generic_getpages() to implement the previous behaviour. 494 * 495 * All other FS's should use the bypass to get to the local media 496 * backing vp's VOP_GETPAGES. 497 */ 498 static int 499 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 500 { 501 int rtval; 502 struct vnode *vp; 503 504 vp = object->handle; 505 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess); 506 if (rtval == EOPNOTSUPP) 507 panic("vnode_pager: vfs's must implement vop_getpages"); 508 return rtval; 509 } 510 511 /* 512 * This is now called from local media FS's to operate against their 513 * own vnodes if they fail to implement VOP_GETPAGES. 514 * 515 * With all the caching local media devices do these days there is really 516 * very little point to attempting to restrict the I/O size to contiguous 517 * blocks on-disk, especially if our caller thinks we need all the specified 518 * pages. Just construct and issue a READ. 519 */ 520 int 521 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount, 522 int reqpage, int seqaccess) 523 { 524 struct iovec aiov; 525 struct uio auio; 526 off_t foff; 527 int error; 528 int count; 529 int i; 530 int ioflags; 531 532 /* 533 * Do not do anything if the vnode is bad. 534 */ 535 if (vp->v_mount == NULL) 536 return VM_PAGER_BAD; 537 538 /* 539 * Calculate the number of pages. Since we are paging in whole 540 * pages, adjust bytecount to be an integral multiple of the page 541 * size. It will be clipped to the file EOF later on. 542 */ 543 bytecount = round_page(bytecount); 544 count = bytecount / PAGE_SIZE; 545 546 /* 547 * We could check m[reqpage]->valid here and shortcut the operation, 548 * but doing so breaks read-ahead. Instead assume that the VM 549 * system has already done at least the check, don't worry about 550 * any races, and issue the VOP_READ to allow read-ahead to function. 551 * 552 * This keeps the pipeline full for I/O bound sequentially scanned 553 * mmap()'s 554 */ 555 /* don't shortcut */ 556 557 /* 558 * Discard pages past the file EOF. If the requested page is past 559 * the file EOF we just leave its valid bits set to 0, the caller 560 * expects to maintain ownership of the requested page. If the 561 * entire range is past file EOF discard everything and generate 562 * a pagein error. 563 */ 564 foff = IDX_TO_OFF(mpp[0]->pindex); 565 if (foff >= vp->v_filesize) { 566 for (i = 0; i < count; i++) { 567 if (i != reqpage) 568 vnode_pager_freepage(mpp[i]); 569 } 570 return VM_PAGER_ERROR; 571 } 572 573 if (foff + bytecount > vp->v_filesize) { 574 bytecount = vp->v_filesize - foff; 575 i = round_page(bytecount) / PAGE_SIZE; 576 while (count > i) { 577 --count; 578 if (count != reqpage) 579 vnode_pager_freepage(mpp[count]); 580 } 581 } 582 583 /* 584 * The size of the transfer is bytecount. bytecount will be an 585 * integral multiple of the page size unless it has been clipped 586 * to the file EOF. The transfer cannot exceed the file EOF. 587 * 588 * When dealing with real devices we must round-up to the device 589 * sector size. 590 */ 591 if (vp->v_type == VBLK || vp->v_type == VCHR) { 592 int secmask = vp->v_rdev->si_bsize_phys - 1; 593 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large", secmask + 1)); 594 bytecount = (bytecount + secmask) & ~secmask; 595 } 596 597 /* 598 * Severe hack to avoid deadlocks with the buffer cache 599 */ 600 for (i = 0; i < count; ++i) { 601 vm_page_t mt = mpp[i]; 602 603 vm_page_io_start(mt); 604 vm_page_wakeup(mt); 605 } 606 607 /* 608 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE 609 */ 610 ioflags = IO_VMIO; 611 if (seqaccess) 612 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 613 614 aiov.iov_base = NULL; 615 aiov.iov_len = bytecount; 616 auio.uio_iov = &aiov; 617 auio.uio_iovcnt = 1; 618 auio.uio_offset = foff; 619 auio.uio_segflg = UIO_NOCOPY; 620 auio.uio_rw = UIO_READ; 621 auio.uio_resid = bytecount; 622 auio.uio_td = NULL; 623 mycpu->gd_cnt.v_vnodein++; 624 mycpu->gd_cnt.v_vnodepgsin += count; 625 626 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 627 628 /* 629 * Severe hack to avoid deadlocks with the buffer cache 630 */ 631 for (i = 0; i < count; ++i) { 632 vm_page_busy_wait(mpp[i], FALSE, "getpgs"); 633 vm_page_io_finish(mpp[i]); 634 } 635 636 /* 637 * Calculate the actual number of bytes read and clean up the 638 * page list. 639 */ 640 bytecount -= auio.uio_resid; 641 642 for (i = 0; i < count; ++i) { 643 vm_page_t mt = mpp[i]; 644 645 if (i != reqpage) { 646 if (error == 0 && mt->valid) { 647 if (mt->flags & PG_REFERENCED) 648 vm_page_activate(mt); 649 else 650 vm_page_deactivate(mt); 651 vm_page_wakeup(mt); 652 } else { 653 vnode_pager_freepage(mt); 654 } 655 } else if (mt->valid == 0) { 656 if (error == 0) { 657 kprintf("page failed but no I/O error page " 658 "%p object %p pindex %d\n", 659 mt, mt->object, (int) mt->pindex); 660 /* whoops, something happened */ 661 error = EINVAL; 662 } 663 } else if (mt->valid != VM_PAGE_BITS_ALL) { 664 /* 665 * Zero-extend the requested page if necessary (if 666 * the filesystem is using a small block size). 667 */ 668 vm_page_zero_invalid(mt, TRUE); 669 } 670 } 671 if (error) { 672 kprintf("vnode_pager_getpage: I/O read error\n"); 673 } 674 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 675 } 676 677 /* 678 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 679 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 680 * vnode_pager_generic_putpages() to implement the previous behaviour. 681 * 682 * Caller has already cleared the pmap modified bits, if any. 683 * 684 * All other FS's should use the bypass to get to the local media 685 * backing vp's VOP_PUTPAGES. 686 */ 687 static void 688 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 689 boolean_t sync, int *rtvals) 690 { 691 int rtval; 692 struct vnode *vp; 693 int bytes = count * PAGE_SIZE; 694 695 /* 696 * Force synchronous operation if we are extremely low on memory 697 * to prevent a low-memory deadlock. VOP operations often need to 698 * allocate more memory to initiate the I/O ( i.e. do a BMAP 699 * operation ). The swapper handles the case by limiting the amount 700 * of asynchronous I/O, but that sort of solution doesn't scale well 701 * for the vnode pager without a lot of work. 702 * 703 * Also, the backing vnode's iodone routine may not wake the pageout 704 * daemon up. This should be probably be addressed XXX. 705 */ 706 707 if ((vmstats.v_free_count + vmstats.v_cache_count) < 708 vmstats.v_pageout_free_min) { 709 sync |= OBJPC_SYNC; 710 } 711 712 /* 713 * Call device-specific putpages function 714 */ 715 vp = object->handle; 716 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 717 if (rtval == EOPNOTSUPP) { 718 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 719 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 720 } 721 } 722 723 724 /* 725 * This is now called from local media FS's to operate against their 726 * own vnodes if they fail to implement VOP_PUTPAGES. 727 * 728 * This is typically called indirectly via the pageout daemon and 729 * clustering has already typically occured, so in general we ask the 730 * underlying filesystem to write the data out asynchronously rather 731 * then delayed. 732 */ 733 int 734 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 735 int flags, int *rtvals) 736 { 737 int i; 738 int maxsize, ncount, count; 739 vm_ooffset_t poffset; 740 struct uio auio; 741 struct iovec aiov; 742 int error; 743 int ioflags; 744 745 count = bytecount / PAGE_SIZE; 746 747 for (i = 0; i < count; i++) 748 rtvals[i] = VM_PAGER_AGAIN; 749 750 if ((int) m[0]->pindex < 0) { 751 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 752 (long)m[0]->pindex, m[0]->dirty); 753 rtvals[0] = VM_PAGER_BAD; 754 return VM_PAGER_BAD; 755 } 756 757 maxsize = count * PAGE_SIZE; 758 ncount = count; 759 760 poffset = IDX_TO_OFF(m[0]->pindex); 761 762 /* 763 * If the page-aligned write is larger then the actual file we 764 * have to invalidate pages occuring beyond the file EOF. 765 * 766 * If the file EOF resides in the middle of a page we still clear 767 * all of that page's dirty bits later on. If we didn't it would 768 * endlessly re-write. 769 * 770 * We do not under any circumstances truncate the valid bits, as 771 * this will screw up bogus page replacement. 772 * 773 * The caller has already read-protected the pages. The VFS must 774 * use the buffer cache to wrap the pages. The pages might not 775 * be immediately flushed by the buffer cache but once under its 776 * control the pages themselves can wind up being marked clean 777 * and their covering buffer cache buffer can be marked dirty. 778 */ 779 if (poffset + maxsize > vp->v_filesize) { 780 if (poffset < vp->v_filesize) { 781 maxsize = vp->v_filesize - poffset; 782 ncount = btoc(maxsize); 783 } else { 784 maxsize = 0; 785 ncount = 0; 786 } 787 if (ncount < count) { 788 for (i = ncount; i < count; i++) { 789 rtvals[i] = VM_PAGER_BAD; 790 } 791 } 792 } 793 794 /* 795 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 796 * rather then a bdwrite() to prevent paging I/O from saturating 797 * the buffer cache. Dummy-up the sequential heuristic to cause 798 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 799 * the system decides how to cluster. 800 */ 801 ioflags = IO_VMIO; 802 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 803 ioflags |= IO_SYNC; 804 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 805 ioflags |= IO_ASYNC; 806 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 807 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 808 809 aiov.iov_base = (caddr_t) 0; 810 aiov.iov_len = maxsize; 811 auio.uio_iov = &aiov; 812 auio.uio_iovcnt = 1; 813 auio.uio_offset = poffset; 814 auio.uio_segflg = UIO_NOCOPY; 815 auio.uio_rw = UIO_WRITE; 816 auio.uio_resid = maxsize; 817 auio.uio_td = NULL; 818 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 819 mycpu->gd_cnt.v_vnodeout++; 820 mycpu->gd_cnt.v_vnodepgsout += ncount; 821 822 if (error) { 823 krateprintf(&vbadrate, 824 "vnode_pager_putpages: I/O error %d\n", error); 825 } 826 if (auio.uio_resid) { 827 krateprintf(&vresrate, 828 "vnode_pager_putpages: residual I/O %zd at %lu\n", 829 auio.uio_resid, (u_long)m[0]->pindex); 830 } 831 if (error == 0) { 832 for (i = 0; i < ncount; i++) { 833 rtvals[i] = VM_PAGER_OK; 834 vm_page_undirty(m[i]); 835 } 836 } 837 return rtvals[0]; 838 } 839 840 /* 841 * Run the chain and if the bottom-most object is a vnode-type lock the 842 * underlying vnode. A locked vnode or NULL is returned. 843 */ 844 struct vnode * 845 vnode_pager_lock(vm_object_t object) 846 { 847 struct vnode *vp = NULL; 848 vm_object_t lobject; 849 vm_object_t tobject; 850 int error; 851 852 if (object == NULL) 853 return(NULL); 854 855 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 856 lobject = object; 857 858 while (lobject->type != OBJT_VNODE) { 859 if (lobject->flags & OBJ_DEAD) 860 break; 861 tobject = lobject->backing_object; 862 if (tobject == NULL) 863 break; 864 vm_object_hold_shared(tobject); 865 if (tobject == lobject->backing_object) { 866 if (lobject != object) { 867 vm_object_lock_swap(); 868 vm_object_drop(lobject); 869 } 870 lobject = tobject; 871 } else { 872 vm_object_drop(tobject); 873 } 874 } 875 while (lobject->type == OBJT_VNODE && 876 (lobject->flags & OBJ_DEAD) == 0) { 877 /* 878 * Extract the vp 879 */ 880 vp = lobject->handle; 881 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 882 if (error == 0) { 883 if (lobject->handle == vp) 884 break; 885 vput(vp); 886 } else { 887 kprintf("vnode_pager_lock: vp %p error %d " 888 "lockstatus %d, retrying\n", 889 vp, error, 890 lockstatus(&vp->v_lock, curthread)); 891 tsleep(object->handle, 0, "vnpgrl", hz); 892 } 893 vp = NULL; 894 } 895 if (lobject != object) 896 vm_object_drop(lobject); 897 return (vp); 898 } 899