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 * 3. 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 <vm/vm_page2.h> 74 75 static void vnode_pager_dealloc (vm_object_t); 76 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int); 77 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, int, int *); 78 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t); 79 80 struct pagerops vnodepagerops = { 81 vnode_pager_dealloc, 82 vnode_pager_getpage, 83 vnode_pager_putpages, 84 vnode_pager_haspage 85 }; 86 87 static struct krate vbadrate = { 1 }; 88 static struct krate vresrate = { 1 }; 89 90 long vnode_pbuf_freecnt = -1; /* start out unlimited */ 91 92 /* 93 * Allocate a VM object for a vnode, typically a regular file vnode. 94 * 95 * Some additional information is required to generate a properly sized 96 * object which covers the entire buffer cache buffer straddling the file 97 * EOF. Userland does not see the extra pages as the VM fault code tests 98 * against v_filesize. 99 */ 100 vm_object_t 101 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset, 102 int blksize, int boff) 103 { 104 vm_object_t object; 105 struct vnode *vp; 106 off_t loffset; 107 vm_pindex_t lsize; 108 109 /* 110 * Pageout to vnode, no can do yet. 111 */ 112 if (handle == NULL) 113 return (NULL); 114 115 /* 116 * XXX hack - This initialization should be put somewhere else. 117 */ 118 if (vnode_pbuf_freecnt < 0) { 119 vnode_pbuf_freecnt = nswbuf_kva / 2 + 1; 120 } 121 122 /* 123 * Serialize potential vnode/object teardowns and interlocks 124 */ 125 vp = (struct vnode *)handle; 126 lwkt_gettoken(&vp->v_token); 127 128 /* 129 * If the object is being terminated, wait for it to 130 * go away. 131 */ 132 object = vp->v_object; 133 if (object) { 134 vm_object_hold(object); 135 KKASSERT((object->flags & OBJ_DEAD) == 0); 136 } 137 138 if (VREFCNT(vp) <= 0) 139 panic("vnode_pager_alloc: no vnode reference"); 140 141 /* 142 * Round up to the *next* block, then destroy the buffers in question. 143 * Since we are only removing some of the buffers we must rely on the 144 * scan count to determine whether a loop is necessary. 145 * 146 * Destroy any pages beyond the last buffer. 147 */ 148 if (boff < 0) 149 boff = (int)(length % blksize); 150 if (boff) 151 loffset = length + (blksize - boff); 152 else 153 loffset = length; 154 lsize = OFF_TO_IDX(round_page64(loffset)); 155 156 if (object == NULL) { 157 /* 158 * And an object of the appropriate size 159 */ 160 object = vm_object_allocate_hold(OBJT_VNODE, lsize); 161 object->handle = handle; 162 vp->v_object = object; 163 vp->v_filesize = length; 164 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC)) 165 vm_object_set_flag(object, OBJ_NOMSYNC); 166 vref(vp); 167 } else { 168 vm_object_reference_quick(object); /* also vref's */ 169 if (object->size != lsize) { 170 kprintf("vnode_pager_alloc: Warning, objsize " 171 "mismatch %jd/%jd vp=%p obj=%p\n", 172 (intmax_t)object->size, 173 (intmax_t)lsize, 174 vp, object); 175 } 176 if (vp->v_filesize != length) { 177 kprintf("vnode_pager_alloc: Warning, filesize " 178 "mismatch %jd/%jd vp=%p obj=%p\n", 179 (intmax_t)vp->v_filesize, 180 (intmax_t)length, 181 vp, object); 182 } 183 } 184 vm_object_drop(object); 185 lwkt_reltoken(&vp->v_token); 186 187 return (object); 188 } 189 190 /* 191 * Add a ref to a vnode's existing VM object, return the object or 192 * NULL if the vnode did not have one. This does not create the 193 * object (we can't since we don't know what the proper blocksize/boff 194 * is to match the VFS's use of the buffer cache). 195 * 196 * The vnode must be referenced and is typically open. The object should 197 * be stable in this situation. 198 * 199 * Returns the object with an additional reference but not locked. 200 */ 201 vm_object_t 202 vnode_pager_reference(struct vnode *vp) 203 { 204 vm_object_t object; 205 206 if ((object = vp->v_object) != NULL) 207 vm_object_reference_quick(object); /* also vref's vnode */ 208 return (object); 209 } 210 211 static void 212 vnode_pager_dealloc(vm_object_t object) 213 { 214 struct vnode *vp = object->handle; 215 216 if (vp == NULL) 217 panic("vnode_pager_dealloc: pager already dealloced"); 218 219 vm_object_pip_wait(object, "vnpdea"); 220 221 object->handle = NULL; 222 object->type = OBJT_DEAD; 223 vp->v_object = NULL; 224 vp->v_filesize = NOOFFSET; 225 vclrflags(vp, VTEXT | VOBJBUF); 226 swap_pager_freespace_all(object); 227 } 228 229 /* 230 * Return whether the vnode pager has the requested page. 231 */ 232 static boolean_t 233 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex) 234 { 235 struct vnode *vp = object->handle; 236 off_t loffset; 237 off_t doffset; 238 int voff; 239 int bsize; 240 int error; 241 242 /* 243 * If no vp or vp is doomed or marked transparent to VM, we do not 244 * have the page. 245 */ 246 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 247 return FALSE; 248 249 /* 250 * If filesystem no longer mounted or offset beyond end of file we do 251 * not have the page. 252 */ 253 loffset = IDX_TO_OFF(pindex); 254 255 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 256 return FALSE; 257 258 bsize = vp->v_mount->mnt_stat.f_iosize; 259 voff = loffset % bsize; 260 261 /* 262 * XXX (obsolete - before and after pointers are now NULL) 263 * 264 * BMAP returns byte counts before and after, where after 265 * is inclusive of the base page. haspage must return page 266 * counts before and after where after does not include the 267 * base page. 268 * 269 * BMAP is allowed to return a *after of 0 for backwards 270 * compatibility. The base page is still considered valid if 271 * no error is returned. 272 */ 273 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0); 274 if (error) 275 return TRUE; 276 if (doffset == NOOFFSET) 277 return FALSE; 278 return TRUE; 279 } 280 281 /* 282 * Lets the VM system know about a change in size for a file. 283 * We adjust our own internal size and flush any cached pages in 284 * the associated object that are affected by the size change. 285 * 286 * NOTE: This routine may be invoked as a result of a pager put 287 * operation (possibly at object termination time), so we must be careful. 288 * 289 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 290 * we do not blow up on the case. nsize will always be >= 0, however. 291 */ 292 void 293 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 294 { 295 vm_pindex_t nobjsize; 296 vm_pindex_t oobjsize; 297 vm_object_t object; 298 299 object = vp->v_object; 300 if (object == NULL) 301 return; 302 vm_object_hold(object); 303 KKASSERT(vp->v_object == object); 304 305 /* 306 * Hasn't changed size 307 */ 308 if (nsize == vp->v_filesize) { 309 vm_object_drop(object); 310 return; 311 } 312 313 /* 314 * Has changed size. Adjust the VM object's size and v_filesize 315 * before we start scanning pages to prevent new pages from being 316 * allocated during the scan. 317 */ 318 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 319 oobjsize = object->size; 320 object->size = nobjsize; 321 322 /* 323 * File has shrunk. Toss any cached pages beyond the new EOF. 324 */ 325 if (nsize < vp->v_filesize) { 326 vp->v_filesize = nsize; 327 if (nobjsize < oobjsize) { 328 vm_object_page_remove(object, nobjsize, oobjsize, 329 FALSE); 330 } 331 /* 332 * This gets rid of garbage at the end of a page that is now 333 * only partially backed by the vnode. Since we are setting 334 * the entire page valid & clean after we are done we have 335 * to be sure that the portion of the page within the file 336 * bounds is already valid. If it isn't then making it 337 * valid would create a corrupt block. 338 */ 339 if (nsize & PAGE_MASK) { 340 vm_offset_t kva; 341 vm_page_t m; 342 343 m = vm_page_lookup_busy_wait(object, OFF_TO_IDX(nsize), 344 TRUE, "vsetsz"); 345 346 if (m && m->valid) { 347 int base = (int)nsize & PAGE_MASK; 348 int size = PAGE_SIZE - base; 349 struct lwbuf *lwb; 350 struct lwbuf lwb_cache; 351 352 /* 353 * Clear out partial-page garbage in case 354 * the page has been mapped. 355 * 356 * This is byte aligned. 357 */ 358 lwb = lwbuf_alloc(m, &lwb_cache); 359 kva = lwbuf_kva(lwb); 360 bzero((caddr_t)kva + base, size); 361 lwbuf_free(lwb); 362 363 /* 364 * XXX work around SMP data integrity race 365 * by unmapping the page from user processes. 366 * The garbage we just cleared may be mapped 367 * to a user process running on another cpu 368 * and this code is not running through normal 369 * I/O channels which handle SMP issues for 370 * us, so unmap page to synchronize all cpus. 371 * 372 * XXX should vm_pager_unmap_page() have 373 * dealt with this? 374 */ 375 vm_page_protect(m, VM_PROT_NONE); 376 377 /* 378 * Clear out partial-page dirty bits. This 379 * has the side effect of setting the valid 380 * bits, but that is ok. There are a bunch 381 * of places in the VM system where we expected 382 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 383 * case is one of them. If the page is still 384 * partially dirty, make it fully dirty. 385 * 386 * NOTE: We do not clear out the valid 387 * bits. This would prevent bogus_page 388 * replacement from working properly. 389 * 390 * NOTE: We do not want to clear the dirty 391 * bit for a partial DEV_BSIZE'd truncation! 392 * This is DEV_BSIZE aligned! 393 */ 394 vm_page_clear_dirty_beg_nonincl(m, base, size); 395 if (m->dirty != 0) 396 m->dirty = VM_PAGE_BITS_ALL; 397 vm_page_wakeup(m); 398 } else if (m) { 399 vm_page_wakeup(m); 400 } 401 } 402 } else { 403 vp->v_filesize = nsize; 404 } 405 vm_object_drop(object); 406 } 407 408 /* 409 * Release a page busied for a getpages operation. The page may have become 410 * wired (typically due to being used by the buffer cache) or otherwise been 411 * soft-busied and cannot be freed in that case. A held page can still be 412 * freed. 413 */ 414 void 415 vnode_pager_freepage(vm_page_t m) 416 { 417 if ((m->busy_count & PBUSY_MASK) || 418 m->wire_count || 419 (m->flags & PG_NEED_COMMIT)) { 420 vm_page_activate(m); 421 vm_page_wakeup(m); 422 } else { 423 vm_page_free(m); 424 } 425 } 426 427 /* 428 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 429 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 430 * vnode_pager_generic_getpages() to implement the previous behaviour. 431 * 432 * All other FS's should use the bypass to get to the local media 433 * backing vp's VOP_GETPAGES. 434 */ 435 static int 436 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 437 { 438 int rtval; 439 struct vnode *vp; 440 441 vp = object->handle; 442 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess); 443 if (rtval == EOPNOTSUPP) 444 panic("vnode_pager: vfs's must implement vop_getpages"); 445 return rtval; 446 } 447 448 /* 449 * This is now called from local media FS's to operate against their 450 * own vnodes if they fail to implement VOP_GETPAGES. 451 * 452 * With all the caching local media devices do these days there is really 453 * very little point to attempting to restrict the I/O size to contiguous 454 * blocks on-disk, especially if our caller thinks we need all the specified 455 * pages. Just construct and issue a READ. 456 */ 457 int 458 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount, 459 int reqpage, int seqaccess) 460 { 461 struct iovec aiov; 462 struct uio auio; 463 off_t foff; 464 int error; 465 int count; 466 int i; 467 int ioflags; 468 int obytecount; 469 470 /* 471 * Do not do anything if the vnode is bad. 472 */ 473 if (vp->v_mount == NULL) 474 return VM_PAGER_BAD; 475 476 /* 477 * Calculate the number of pages. Since we are paging in whole 478 * pages, adjust bytecount to be an integral multiple of the page 479 * size. It will be clipped to the file EOF later on. 480 */ 481 bytecount = round_page(bytecount); 482 count = bytecount / PAGE_SIZE; 483 484 /* 485 * We could check m[reqpage]->valid here and shortcut the operation, 486 * but doing so breaks read-ahead. Instead assume that the VM 487 * system has already done at least the check, don't worry about 488 * any races, and issue the VOP_READ to allow read-ahead to function. 489 * 490 * This keeps the pipeline full for I/O bound sequentially scanned 491 * mmap()'s 492 */ 493 /* don't shortcut */ 494 495 /* 496 * Discard pages past the file EOF. If the requested page is past 497 * the file EOF we just leave its valid bits set to 0, the caller 498 * expects to maintain ownership of the requested page. If the 499 * entire range is past file EOF discard everything and generate 500 * a pagein error. 501 */ 502 foff = IDX_TO_OFF(mpp[0]->pindex); 503 if (foff >= vp->v_filesize) { 504 for (i = 0; i < count; i++) { 505 if (i != reqpage) 506 vnode_pager_freepage(mpp[i]); 507 } 508 return VM_PAGER_ERROR; 509 } 510 511 if (foff + bytecount > vp->v_filesize) { 512 bytecount = vp->v_filesize - foff; 513 i = round_page(bytecount) / PAGE_SIZE; 514 while (count > i) { 515 --count; 516 if (count != reqpage) 517 vnode_pager_freepage(mpp[count]); 518 } 519 } 520 521 /* 522 * The size of the transfer is bytecount. bytecount will be an 523 * integral multiple of the page size unless it has been clipped 524 * to the file EOF. The transfer cannot exceed the file EOF. 525 * 526 * When dealing with real devices we must round-up to the device 527 * sector size. 528 */ 529 if (vp->v_type == VBLK || vp->v_type == VCHR) { 530 int secmask = vp->v_rdev->si_bsize_phys - 1; 531 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large", secmask + 1)); 532 bytecount = (bytecount + secmask) & ~secmask; 533 } 534 obytecount = bytecount; 535 536 /* 537 * Severe hack to avoid deadlocks with the buffer cache 538 */ 539 for (i = 0; i < count; ++i) { 540 vm_page_t mt = mpp[i]; 541 542 vm_page_io_start(mt); 543 vm_page_wakeup(mt); 544 } 545 546 /* 547 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE 548 */ 549 ioflags = IO_VMIO; 550 if (seqaccess) 551 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 552 553 aiov.iov_base = NULL; 554 aiov.iov_len = bytecount; 555 auio.uio_iov = &aiov; 556 auio.uio_iovcnt = 1; 557 auio.uio_offset = foff; 558 auio.uio_segflg = UIO_NOCOPY; 559 auio.uio_rw = UIO_READ; 560 auio.uio_resid = bytecount; 561 auio.uio_td = NULL; 562 mycpu->gd_cnt.v_vnodein++; 563 mycpu->gd_cnt.v_vnodepgsin += count; 564 565 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 566 567 /* 568 * Severe hack to avoid deadlocks with the buffer cache 569 */ 570 for (i = 0; i < count; ++i) { 571 vm_page_busy_wait(mpp[i], FALSE, "getpgs"); 572 vm_page_io_finish(mpp[i]); 573 } 574 575 /* 576 * Calculate the actual number of bytes read and clean up the 577 * page list. 578 */ 579 bytecount -= auio.uio_resid; 580 581 for (i = 0; i < count; ++i) { 582 vm_page_t mt = mpp[i]; 583 584 if (i != reqpage) { 585 if (error == 0 && mt->valid) { 586 if (mt->flags & PG_REFERENCED) 587 vm_page_activate(mt); 588 else 589 vm_page_deactivate(mt); 590 vm_page_wakeup(mt); 591 } else { 592 vnode_pager_freepage(mt); 593 } 594 } else if (mt->valid == 0) { 595 if (error == 0) { 596 kprintf("page failed but no I/O error page " 597 "%p object %p pindex %d\n", 598 mt, mt->object, (int) mt->pindex); 599 kprintf("i=%d foff=%016lx bytecount=%d/%d " 600 "uioresid=%zd\n", 601 i, foff, obytecount, bytecount, 602 auio.uio_resid); 603 /* whoops, something happened */ 604 error = EINVAL; 605 } 606 } else if (mt->valid != VM_PAGE_BITS_ALL) { 607 /* 608 * Zero-extend the requested page if necessary (if 609 * the filesystem is using a small block size). 610 */ 611 vm_page_zero_invalid(mt, TRUE); 612 } 613 } 614 if (error) { 615 kprintf("vnode_pager_getpage: I/O read error\n"); 616 } 617 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 618 } 619 620 /* 621 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 622 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 623 * vnode_pager_generic_putpages() to implement the previous behaviour. 624 * 625 * Caller has already cleared the pmap modified bits, if any. 626 * 627 * All other FS's should use the bypass to get to the local media 628 * backing vp's VOP_PUTPAGES. 629 */ 630 static void 631 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 632 int sync, int *rtvals) 633 { 634 int rtval; 635 struct vnode *vp; 636 int bytes = count * PAGE_SIZE; 637 638 /* 639 * Force synchronous operation if we are extremely low on memory 640 * to prevent a low-memory deadlock. VOP operations often need to 641 * allocate more memory to initiate the I/O ( i.e. do a BMAP 642 * operation ). The swapper handles the case by limiting the amount 643 * of asynchronous I/O, but that sort of solution doesn't scale well 644 * for the vnode pager without a lot of work. 645 * 646 * Also, the backing vnode's iodone routine may not wake the pageout 647 * daemon up. This should be probably be addressed XXX. 648 */ 649 650 if ((vmstats.v_free_count + vmstats.v_cache_count) < 651 vmstats.v_pageout_free_min) { 652 sync |= OBJPC_SYNC; 653 } 654 655 /* 656 * Call device-specific putpages function 657 */ 658 vp = object->handle; 659 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 660 if (rtval == EOPNOTSUPP) { 661 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 662 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 663 } 664 } 665 666 667 /* 668 * This is now called from local media FS's to operate against their 669 * own vnodes if they fail to implement VOP_PUTPAGES. 670 * 671 * This is typically called indirectly via the pageout daemon and 672 * clustering has already typically occured, so in general we ask the 673 * underlying filesystem to write the data out asynchronously rather 674 * then delayed. 675 */ 676 int 677 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 678 int flags, int *rtvals) 679 { 680 int i; 681 int maxsize, ncount, count; 682 vm_ooffset_t poffset; 683 struct uio auio; 684 struct iovec aiov; 685 int error; 686 int ioflags; 687 688 count = bytecount / PAGE_SIZE; 689 690 for (i = 0; i < count; i++) 691 rtvals[i] = VM_PAGER_AGAIN; 692 693 if ((int) m[0]->pindex < 0) { 694 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 695 (long)m[0]->pindex, m[0]->dirty); 696 rtvals[0] = VM_PAGER_BAD; 697 return VM_PAGER_BAD; 698 } 699 700 maxsize = count * PAGE_SIZE; 701 ncount = count; 702 703 poffset = IDX_TO_OFF(m[0]->pindex); 704 705 /* 706 * If the page-aligned write is larger then the actual file we 707 * have to invalidate pages occuring beyond the file EOF. 708 * 709 * If the file EOF resides in the middle of a page we still clear 710 * all of that page's dirty bits later on. If we didn't it would 711 * endlessly re-write. 712 * 713 * We do not under any circumstances truncate the valid bits, as 714 * this will screw up bogus page replacement. 715 * 716 * The caller has already read-protected the pages. The VFS must 717 * use the buffer cache to wrap the pages. The pages might not 718 * be immediately flushed by the buffer cache but once under its 719 * control the pages themselves can wind up being marked clean 720 * and their covering buffer cache buffer can be marked dirty. 721 */ 722 if (poffset + maxsize > vp->v_filesize) { 723 if (poffset < vp->v_filesize) { 724 maxsize = vp->v_filesize - poffset; 725 ncount = btoc(maxsize); 726 } else { 727 maxsize = 0; 728 ncount = 0; 729 } 730 if (ncount < count) { 731 for (i = ncount; i < count; i++) { 732 rtvals[i] = VM_PAGER_BAD; 733 } 734 } 735 } 736 737 /* 738 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 739 * rather then a bdwrite() to prevent paging I/O from saturating 740 * the buffer cache. Dummy-up the sequential heuristic to cause 741 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 742 * the system decides how to cluster. 743 */ 744 ioflags = IO_VMIO; 745 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 746 ioflags |= IO_SYNC; 747 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 748 ioflags |= IO_ASYNC; 749 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 750 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 751 752 aiov.iov_base = (caddr_t) 0; 753 aiov.iov_len = maxsize; 754 auio.uio_iov = &aiov; 755 auio.uio_iovcnt = 1; 756 auio.uio_offset = poffset; 757 auio.uio_segflg = UIO_NOCOPY; 758 auio.uio_rw = UIO_WRITE; 759 auio.uio_resid = maxsize; 760 auio.uio_td = NULL; 761 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 762 mycpu->gd_cnt.v_vnodeout++; 763 mycpu->gd_cnt.v_vnodepgsout += ncount; 764 765 if (error) { 766 krateprintf(&vbadrate, 767 "vnode_pager_putpages: I/O error %d\n", error); 768 } 769 if (auio.uio_resid) { 770 krateprintf(&vresrate, 771 "vnode_pager_putpages: residual I/O %zd at %lu\n", 772 auio.uio_resid, (u_long)m[0]->pindex); 773 } 774 if (error == 0) { 775 for (i = 0; i < ncount; i++) { 776 rtvals[i] = VM_PAGER_OK; 777 vm_page_undirty(m[i]); 778 } 779 } 780 return rtvals[0]; 781 } 782 783 /* 784 * Run the chain and if the bottom-most object is a vnode-type lock the 785 * underlying vnode. A locked vnode or NULL is returned. 786 */ 787 struct vnode * 788 vnode_pager_lock(vm_object_t object) 789 { 790 struct vnode *vp = NULL; 791 vm_object_t lobject; 792 vm_object_t tobject; 793 int error; 794 795 if (object == NULL) 796 return(NULL); 797 798 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 799 lobject = object; 800 801 while (lobject->type != OBJT_VNODE) { 802 if (lobject->flags & OBJ_DEAD) 803 break; 804 tobject = lobject->backing_object; 805 if (tobject == NULL) 806 break; 807 vm_object_hold_shared(tobject); 808 if (tobject == lobject->backing_object) { 809 if (lobject != object) { 810 vm_object_lock_swap(); 811 vm_object_drop(lobject); 812 } 813 lobject = tobject; 814 } else { 815 vm_object_drop(tobject); 816 } 817 } 818 while (lobject->type == OBJT_VNODE && 819 (lobject->flags & OBJ_DEAD) == 0) { 820 /* 821 * Extract the vp 822 */ 823 vp = lobject->handle; 824 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 825 if (error == 0) { 826 if (lobject->handle == vp) 827 break; 828 vput(vp); 829 } else { 830 kprintf("vnode_pager_lock: vp %p error %d " 831 "lockstatus %d, retrying\n", 832 vp, error, 833 lockstatus(&vp->v_lock, curthread)); 834 tsleep(object->handle, 0, "vnpgrl", hz); 835 } 836 vp = NULL; 837 } 838 if (lobject != object) 839 vm_object_drop(lobject); 840 return (vp); 841 } 842