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. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 43 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $ 44 * $DragonFly: src/sys/vm/vnode_pager.c,v 1.43 2008/06/19 23:27:39 dillon Exp $ 45 */ 46 47 /* 48 * Page to/from files (vnodes). 49 */ 50 51 /* 52 * TODO: 53 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 54 * greatly re-simplify the vnode_pager. 55 */ 56 57 #include <sys/param.h> 58 #include <sys/systm.h> 59 #include <sys/kernel.h> 60 #include <sys/proc.h> 61 #include <sys/vnode.h> 62 #include <sys/mount.h> 63 #include <sys/buf.h> 64 #include <sys/vmmeter.h> 65 #include <sys/conf.h> 66 67 #include <cpu/lwbuf.h> 68 69 #include <vm/vm.h> 70 #include <vm/vm_object.h> 71 #include <vm/vm_page.h> 72 #include <vm/vm_pager.h> 73 #include <vm/vm_map.h> 74 #include <vm/vnode_pager.h> 75 #include <vm/swap_pager.h> 76 #include <vm/vm_extern.h> 77 78 #include <sys/thread2.h> 79 #include <vm/vm_page2.h> 80 81 static void vnode_pager_dealloc (vm_object_t); 82 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int); 83 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *); 84 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t); 85 86 struct pagerops vnodepagerops = { 87 vnode_pager_dealloc, 88 vnode_pager_getpage, 89 vnode_pager_putpages, 90 vnode_pager_haspage 91 }; 92 93 static struct krate vbadrate = { 1 }; 94 static struct krate vresrate = { 1 }; 95 96 int vnode_pbuf_freecnt = -1; /* start out unlimited */ 97 98 /* 99 * Allocate a VM object for a vnode, typically a regular file vnode. 100 * 101 * Some additional information is required to generate a properly sized 102 * object which covers the entire buffer cache buffer straddling the file 103 * EOF. Userland does not see the extra pages as the VM fault code tests 104 * against v_filesize. 105 */ 106 vm_object_t 107 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset, 108 int blksize, int boff) 109 { 110 vm_object_t object; 111 struct vnode *vp; 112 off_t loffset; 113 vm_pindex_t lsize; 114 115 /* 116 * Pageout to vnode, no can do yet. 117 */ 118 if (handle == NULL) 119 return (NULL); 120 121 /* 122 * XXX hack - This initialization should be put somewhere else. 123 */ 124 if (vnode_pbuf_freecnt < 0) { 125 vnode_pbuf_freecnt = nswbuf / 2 + 1; 126 } 127 128 /* 129 * Serialize potential vnode/object teardowns and interlocks 130 */ 131 vp = (struct vnode *)handle; 132 lwkt_gettoken(&vp->v_token); 133 134 /* 135 * Prevent race condition when allocating the object. This 136 * can happen with NFS vnodes since the nfsnode isn't locked. 137 */ 138 while (vp->v_flag & VOLOCK) { 139 vsetflags(vp, VOWANT); 140 tsleep(vp, 0, "vnpobj", 0); 141 } 142 vsetflags(vp, VOLOCK); 143 lwkt_reltoken(&vp->v_token); 144 145 /* 146 * If the object is being terminated, wait for it to 147 * go away. 148 */ 149 while ((object = vp->v_object) != NULL) { 150 vm_object_hold(object); 151 if ((object->flags & OBJ_DEAD) == 0) 152 break; 153 vm_object_dead_sleep(object, "vadead"); 154 vm_object_drop(object); 155 } 156 157 if (vp->v_sysref.refcnt <= 0) 158 panic("vnode_pager_alloc: no vnode reference"); 159 160 /* 161 * Round up to the *next* block, then destroy the buffers in question. 162 * Since we are only removing some of the buffers we must rely on the 163 * scan count to determine whether a loop is necessary. 164 * 165 * Destroy any pages beyond the last buffer. 166 */ 167 if (boff < 0) 168 boff = (int)(length % blksize); 169 if (boff) 170 loffset = length + (blksize - boff); 171 else 172 loffset = length; 173 lsize = OFF_TO_IDX(round_page64(loffset)); 174 175 if (object == NULL) { 176 /* 177 * And an object of the appropriate size 178 */ 179 object = vm_object_allocate_hold(OBJT_VNODE, lsize); 180 object->flags = 0; 181 object->handle = handle; 182 vp->v_object = object; 183 vp->v_filesize = length; 184 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC)) 185 vm_object_set_flag(object, OBJ_NOMSYNC); 186 } else { 187 object->ref_count++; 188 if (object->size != lsize) { 189 kprintf("vnode_pager_alloc: Warning, objsize " 190 "mismatch %jd/%jd vp=%p obj=%p\n", 191 (intmax_t)object->size, 192 (intmax_t)lsize, 193 vp, object); 194 } 195 if (vp->v_filesize != length) { 196 kprintf("vnode_pager_alloc: Warning, filesize " 197 "mismatch %jd/%jd vp=%p obj=%p\n", 198 (intmax_t)vp->v_filesize, 199 (intmax_t)length, 200 vp, object); 201 } 202 } 203 204 vref(vp); 205 lwkt_gettoken(&vp->v_token); 206 vclrflags(vp, VOLOCK); 207 if (vp->v_flag & VOWANT) { 208 vclrflags(vp, VOWANT); 209 wakeup(vp); 210 } 211 lwkt_reltoken(&vp->v_token); 212 213 vm_object_drop(object); 214 215 return (object); 216 } 217 218 /* 219 * Add a ref to a vnode's existing VM object, return the object or 220 * NULL if the vnode did not have one. This does not create the 221 * object (we can't since we don't know what the proper blocksize/boff 222 * is to match the VFS's use of the buffer cache). 223 */ 224 vm_object_t 225 vnode_pager_reference(struct vnode *vp) 226 { 227 vm_object_t object; 228 229 /* 230 * Prevent race condition when allocating the object. This 231 * can happen with NFS vnodes since the nfsnode isn't locked. 232 * 233 * Serialize potential vnode/object teardowns and interlocks 234 */ 235 lwkt_gettoken(&vp->v_token); 236 while (vp->v_flag & VOLOCK) { 237 vsetflags(vp, VOWANT); 238 tsleep(vp, 0, "vnpobj", 0); 239 } 240 vsetflags(vp, VOLOCK); 241 lwkt_reltoken(&vp->v_token); 242 243 /* 244 * Prevent race conditions against deallocation of the VM 245 * object. 246 */ 247 while ((object = vp->v_object) != NULL) { 248 vm_object_hold(object); 249 if ((object->flags & OBJ_DEAD) == 0) 250 break; 251 vm_object_dead_sleep(object, "vadead"); 252 vm_object_drop(object); 253 } 254 255 /* 256 * The object is expected to exist, the caller will handle 257 * NULL returns if it does not. 258 */ 259 if (object) { 260 object->ref_count++; 261 vref(vp); 262 } 263 264 lwkt_gettoken(&vp->v_token); 265 vclrflags(vp, VOLOCK); 266 if (vp->v_flag & VOWANT) { 267 vclrflags(vp, VOWANT); 268 wakeup(vp); 269 } 270 lwkt_reltoken(&vp->v_token); 271 if (object) 272 vm_object_drop(object); 273 274 return (object); 275 } 276 277 static void 278 vnode_pager_dealloc(vm_object_t object) 279 { 280 struct vnode *vp = object->handle; 281 282 if (vp == NULL) 283 panic("vnode_pager_dealloc: pager already dealloced"); 284 285 vm_object_pip_wait(object, "vnpdea"); 286 287 object->handle = NULL; 288 object->type = OBJT_DEAD; 289 vp->v_object = NULL; 290 vp->v_filesize = NOOFFSET; 291 vclrflags(vp, VTEXT | VOBJBUF); 292 swap_pager_freespace_all(object); 293 } 294 295 /* 296 * Return whether the vnode pager has the requested page. Return the 297 * number of disk-contiguous pages before and after the requested page, 298 * not including the requested page. 299 */ 300 static boolean_t 301 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex) 302 { 303 struct vnode *vp = object->handle; 304 off_t loffset; 305 off_t doffset; 306 int voff; 307 int bsize; 308 int error; 309 310 /* 311 * If no vp or vp is doomed or marked transparent to VM, we do not 312 * have the page. 313 */ 314 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 315 return FALSE; 316 317 /* 318 * If filesystem no longer mounted or offset beyond end of file we do 319 * not have the page. 320 */ 321 loffset = IDX_TO_OFF(pindex); 322 323 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 324 return FALSE; 325 326 bsize = vp->v_mount->mnt_stat.f_iosize; 327 voff = loffset % bsize; 328 329 /* 330 * XXX 331 * 332 * BMAP returns byte counts before and after, where after 333 * is inclusive of the base page. haspage must return page 334 * counts before and after where after does not include the 335 * base page. 336 * 337 * BMAP is allowed to return a *after of 0 for backwards 338 * compatibility. The base page is still considered valid if 339 * no error is returned. 340 */ 341 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0); 342 if (error) 343 return TRUE; 344 if (doffset == NOOFFSET) 345 return FALSE; 346 return TRUE; 347 } 348 349 /* 350 * Lets the VM system know about a change in size for a file. 351 * We adjust our own internal size and flush any cached pages in 352 * the associated object that are affected by the size change. 353 * 354 * NOTE: This routine may be invoked as a result of a pager put 355 * operation (possibly at object termination time), so we must be careful. 356 * 357 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 358 * we do not blow up on the case. nsize will always be >= 0, however. 359 */ 360 void 361 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 362 { 363 vm_pindex_t nobjsize; 364 vm_pindex_t oobjsize; 365 vm_object_t object; 366 367 while ((object = vp->v_object) != NULL) { 368 vm_object_hold(object); 369 if (vp->v_object == object) 370 break; 371 vm_object_drop(object); 372 } 373 if (object == NULL) 374 return; 375 376 /* 377 * Hasn't changed size 378 */ 379 if (nsize == vp->v_filesize) { 380 vm_object_drop(object); 381 return; 382 } 383 384 /* 385 * Has changed size. Adjust the VM object's size and v_filesize 386 * before we start scanning pages to prevent new pages from being 387 * allocated during the scan. 388 */ 389 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 390 oobjsize = object->size; 391 object->size = nobjsize; 392 393 /* 394 * File has shrunk. Toss any cached pages beyond the new EOF. 395 */ 396 if (nsize < vp->v_filesize) { 397 vp->v_filesize = nsize; 398 if (nobjsize < oobjsize) { 399 vm_object_page_remove(object, nobjsize, oobjsize, 400 FALSE); 401 } 402 /* 403 * This gets rid of garbage at the end of a page that is now 404 * only partially backed by the vnode. Since we are setting 405 * the entire page valid & clean after we are done we have 406 * to be sure that the portion of the page within the file 407 * bounds is already valid. If it isn't then making it 408 * valid would create a corrupt block. 409 */ 410 if (nsize & PAGE_MASK) { 411 vm_offset_t kva; 412 vm_page_t m; 413 414 m = vm_page_lookup_busy_wait(object, OFF_TO_IDX(nsize), 415 TRUE, "vsetsz"); 416 417 if (m && m->valid) { 418 int base = (int)nsize & PAGE_MASK; 419 int size = PAGE_SIZE - base; 420 struct lwbuf *lwb; 421 struct lwbuf lwb_cache; 422 423 /* 424 * Clear out partial-page garbage in case 425 * the page has been mapped. 426 * 427 * This is byte aligned. 428 */ 429 lwb = lwbuf_alloc(m, &lwb_cache); 430 kva = lwbuf_kva(lwb); 431 bzero((caddr_t)kva + base, size); 432 lwbuf_free(lwb); 433 434 /* 435 * XXX work around SMP data integrity race 436 * by unmapping the page from user processes. 437 * The garbage we just cleared may be mapped 438 * to a user process running on another cpu 439 * and this code is not running through normal 440 * I/O channels which handle SMP issues for 441 * us, so unmap page to synchronize all cpus. 442 * 443 * XXX should vm_pager_unmap_page() have 444 * dealt with this? 445 */ 446 vm_page_protect(m, VM_PROT_NONE); 447 448 /* 449 * Clear out partial-page dirty bits. This 450 * has the side effect of setting the valid 451 * bits, but that is ok. There are a bunch 452 * of places in the VM system where we expected 453 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 454 * case is one of them. If the page is still 455 * partially dirty, make it fully dirty. 456 * 457 * NOTE: We do not clear out the valid 458 * bits. This would prevent bogus_page 459 * replacement from working properly. 460 * 461 * NOTE: We do not want to clear the dirty 462 * bit for a partial DEV_BSIZE'd truncation! 463 * This is DEV_BSIZE aligned! 464 */ 465 vm_page_clear_dirty_beg_nonincl(m, base, size); 466 if (m->dirty != 0) 467 m->dirty = VM_PAGE_BITS_ALL; 468 vm_page_wakeup(m); 469 } else if (m) { 470 vm_page_wakeup(m); 471 } 472 } 473 } else { 474 vp->v_filesize = nsize; 475 } 476 vm_object_drop(object); 477 } 478 479 /* 480 * Release a page busied for a getpages operation. The page may have become 481 * wired (typically due to being used by the buffer cache) or otherwise been 482 * soft-busied and cannot be freed in that case. A held page can still be 483 * freed. 484 */ 485 void 486 vnode_pager_freepage(vm_page_t m) 487 { 488 if (m->busy || m->wire_count) { 489 vm_page_activate(m); 490 vm_page_wakeup(m); 491 } else { 492 vm_page_free(m); 493 } 494 } 495 496 /* 497 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 498 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 499 * vnode_pager_generic_getpages() to implement the previous behaviour. 500 * 501 * All other FS's should use the bypass to get to the local media 502 * backing vp's VOP_GETPAGES. 503 */ 504 static int 505 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 506 { 507 int rtval; 508 struct vnode *vp; 509 510 vp = object->handle; 511 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess); 512 if (rtval == EOPNOTSUPP) 513 panic("vnode_pager: vfs's must implement vop_getpages\n"); 514 return rtval; 515 } 516 517 /* 518 * This is now called from local media FS's to operate against their 519 * own vnodes if they fail to implement VOP_GETPAGES. 520 * 521 * With all the caching local media devices do these days there is really 522 * very little point to attempting to restrict the I/O size to contiguous 523 * blocks on-disk, especially if our caller thinks we need all the specified 524 * pages. Just construct and issue a READ. 525 */ 526 int 527 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount, 528 int reqpage, int seqaccess) 529 { 530 struct iovec aiov; 531 struct uio auio; 532 off_t foff; 533 int error; 534 int count; 535 int i; 536 int ioflags; 537 538 /* 539 * Do not do anything if the vnode is bad. 540 */ 541 if (vp->v_mount == NULL) 542 return VM_PAGER_BAD; 543 544 /* 545 * Calculate the number of pages. Since we are paging in whole 546 * pages, adjust bytecount to be an integral multiple of the page 547 * size. It will be clipped to the file EOF later on. 548 */ 549 bytecount = round_page(bytecount); 550 count = bytecount / PAGE_SIZE; 551 552 /* 553 * We could check m[reqpage]->valid here and shortcut the operation, 554 * but doing so breaks read-ahead. Instead assume that the VM 555 * system has already done at least the check, don't worry about 556 * any races, and issue the VOP_READ to allow read-ahead to function. 557 * 558 * This keeps the pipeline full for I/O bound sequentially scanned 559 * mmap()'s 560 */ 561 /* don't shortcut */ 562 563 /* 564 * Discard pages past the file EOF. If the requested page is past 565 * the file EOF we just leave its valid bits set to 0, the caller 566 * expects to maintain ownership of the requested page. If the 567 * entire range is past file EOF discard everything and generate 568 * a pagein error. 569 */ 570 foff = IDX_TO_OFF(mpp[0]->pindex); 571 if (foff >= vp->v_filesize) { 572 for (i = 0; i < count; i++) { 573 if (i != reqpage) 574 vnode_pager_freepage(mpp[i]); 575 } 576 return VM_PAGER_ERROR; 577 } 578 579 if (foff + bytecount > vp->v_filesize) { 580 bytecount = vp->v_filesize - foff; 581 i = round_page(bytecount) / PAGE_SIZE; 582 while (count > i) { 583 --count; 584 if (count != reqpage) 585 vnode_pager_freepage(mpp[count]); 586 } 587 } 588 589 /* 590 * The size of the transfer is bytecount. bytecount will be an 591 * integral multiple of the page size unless it has been clipped 592 * to the file EOF. The transfer cannot exceed the file EOF. 593 * 594 * When dealing with real devices we must round-up to the device 595 * sector size. 596 */ 597 if (vp->v_type == VBLK || vp->v_type == VCHR) { 598 int secmask = vp->v_rdev->si_bsize_phys - 1; 599 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 600 bytecount = (bytecount + secmask) & ~secmask; 601 } 602 603 /* 604 * Severe hack to avoid deadlocks with the buffer cache 605 */ 606 for (i = 0; i < count; ++i) { 607 vm_page_t mt = mpp[i]; 608 609 vm_page_io_start(mt); 610 vm_page_wakeup(mt); 611 } 612 613 /* 614 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE 615 */ 616 ioflags = IO_VMIO; 617 if (seqaccess) 618 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 619 620 aiov.iov_base = NULL; 621 aiov.iov_len = bytecount; 622 auio.uio_iov = &aiov; 623 auio.uio_iovcnt = 1; 624 auio.uio_offset = foff; 625 auio.uio_segflg = UIO_NOCOPY; 626 auio.uio_rw = UIO_READ; 627 auio.uio_resid = bytecount; 628 auio.uio_td = NULL; 629 mycpu->gd_cnt.v_vnodein++; 630 mycpu->gd_cnt.v_vnodepgsin += count; 631 632 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 633 634 /* 635 * Severe hack to avoid deadlocks with the buffer cache 636 */ 637 for (i = 0; i < count; ++i) { 638 vm_page_busy_wait(mpp[i], FALSE, "getpgs"); 639 vm_page_io_finish(mpp[i]); 640 } 641 642 /* 643 * Calculate the actual number of bytes read and clean up the 644 * page list. 645 */ 646 bytecount -= auio.uio_resid; 647 648 for (i = 0; i < count; ++i) { 649 vm_page_t mt = mpp[i]; 650 651 if (i != reqpage) { 652 if (error == 0 && mt->valid) { 653 if (mt->flags & PG_REFERENCED) 654 vm_page_activate(mt); 655 else 656 vm_page_deactivate(mt); 657 vm_page_wakeup(mt); 658 } else { 659 vnode_pager_freepage(mt); 660 } 661 } else if (mt->valid == 0) { 662 if (error == 0) { 663 kprintf("page failed but no I/O error page " 664 "%p object %p pindex %d\n", 665 mt, mt->object, (int) mt->pindex); 666 /* whoops, something happened */ 667 error = EINVAL; 668 } 669 } else if (mt->valid != VM_PAGE_BITS_ALL) { 670 /* 671 * Zero-extend the requested page if necessary (if 672 * the filesystem is using a small block size). 673 */ 674 vm_page_zero_invalid(mt, TRUE); 675 } 676 } 677 if (error) { 678 kprintf("vnode_pager_getpage: I/O read error\n"); 679 } 680 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 681 } 682 683 /* 684 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 685 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 686 * vnode_pager_generic_putpages() to implement the previous behaviour. 687 * 688 * Caller has already cleared the pmap modified bits, if any. 689 * 690 * All other FS's should use the bypass to get to the local media 691 * backing vp's VOP_PUTPAGES. 692 */ 693 static void 694 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 695 boolean_t sync, int *rtvals) 696 { 697 int rtval; 698 struct vnode *vp; 699 int bytes = count * PAGE_SIZE; 700 701 /* 702 * Force synchronous operation if we are extremely low on memory 703 * to prevent a low-memory deadlock. VOP operations often need to 704 * allocate more memory to initiate the I/O ( i.e. do a BMAP 705 * operation ). The swapper handles the case by limiting the amount 706 * of asynchronous I/O, but that sort of solution doesn't scale well 707 * for the vnode pager without a lot of work. 708 * 709 * Also, the backing vnode's iodone routine may not wake the pageout 710 * daemon up. This should be probably be addressed XXX. 711 */ 712 713 if ((vmstats.v_free_count + vmstats.v_cache_count) < 714 vmstats.v_pageout_free_min) { 715 sync |= OBJPC_SYNC; 716 } 717 718 /* 719 * Call device-specific putpages function 720 */ 721 vp = object->handle; 722 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 723 if (rtval == EOPNOTSUPP) { 724 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 725 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 726 } 727 } 728 729 730 /* 731 * This is now called from local media FS's to operate against their 732 * own vnodes if they fail to implement VOP_PUTPAGES. 733 * 734 * This is typically called indirectly via the pageout daemon and 735 * clustering has already typically occured, so in general we ask the 736 * underlying filesystem to write the data out asynchronously rather 737 * then delayed. 738 */ 739 int 740 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 741 int flags, int *rtvals) 742 { 743 int i; 744 vm_object_t object; 745 int maxsize, ncount, count; 746 vm_ooffset_t poffset; 747 struct uio auio; 748 struct iovec aiov; 749 int error; 750 int ioflags; 751 752 object = vp->v_object; 753 count = bytecount / PAGE_SIZE; 754 755 for (i = 0; i < count; i++) 756 rtvals[i] = VM_PAGER_AGAIN; 757 758 if ((int) m[0]->pindex < 0) { 759 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 760 (long)m[0]->pindex, m[0]->dirty); 761 rtvals[0] = VM_PAGER_BAD; 762 return VM_PAGER_BAD; 763 } 764 765 maxsize = count * PAGE_SIZE; 766 ncount = count; 767 768 poffset = IDX_TO_OFF(m[0]->pindex); 769 770 /* 771 * If the page-aligned write is larger then the actual file we 772 * have to invalidate pages occuring beyond the file EOF. 773 * 774 * If the file EOF resides in the middle of a page we still clear 775 * all of that page's dirty bits later on. If we didn't it would 776 * endlessly re-write. 777 * 778 * We do not under any circumstances truncate the valid bits, as 779 * this will screw up bogus page replacement. 780 * 781 * The caller has already read-protected the pages. The VFS must 782 * use the buffer cache to wrap the pages. The pages might not 783 * be immediately flushed by the buffer cache but once under its 784 * control the pages themselves can wind up being marked clean 785 * and their covering buffer cache buffer can be marked dirty. 786 */ 787 if (poffset + maxsize > vp->v_filesize) { 788 if (poffset < vp->v_filesize) { 789 maxsize = vp->v_filesize - poffset; 790 ncount = btoc(maxsize); 791 } else { 792 maxsize = 0; 793 ncount = 0; 794 } 795 if (ncount < count) { 796 for (i = ncount; i < count; i++) { 797 rtvals[i] = VM_PAGER_BAD; 798 } 799 } 800 } 801 802 /* 803 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 804 * rather then a bdwrite() to prevent paging I/O from saturating 805 * the buffer cache. Dummy-up the sequential heuristic to cause 806 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 807 * the system decides how to cluster. 808 */ 809 ioflags = IO_VMIO; 810 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 811 ioflags |= IO_SYNC; 812 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 813 ioflags |= IO_ASYNC; 814 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 815 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 816 817 aiov.iov_base = (caddr_t) 0; 818 aiov.iov_len = maxsize; 819 auio.uio_iov = &aiov; 820 auio.uio_iovcnt = 1; 821 auio.uio_offset = poffset; 822 auio.uio_segflg = UIO_NOCOPY; 823 auio.uio_rw = UIO_WRITE; 824 auio.uio_resid = maxsize; 825 auio.uio_td = NULL; 826 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 827 mycpu->gd_cnt.v_vnodeout++; 828 mycpu->gd_cnt.v_vnodepgsout += ncount; 829 830 if (error) { 831 krateprintf(&vbadrate, 832 "vnode_pager_putpages: I/O error %d\n", error); 833 } 834 if (auio.uio_resid) { 835 krateprintf(&vresrate, 836 "vnode_pager_putpages: residual I/O %zd at %lu\n", 837 auio.uio_resid, (u_long)m[0]->pindex); 838 } 839 if (error == 0) { 840 for (i = 0; i < ncount; i++) { 841 rtvals[i] = VM_PAGER_OK; 842 vm_page_undirty(m[i]); 843 } 844 } 845 return rtvals[0]; 846 } 847 848 /* 849 * Run the chain and if the bottom-most object is a vnode-type lock the 850 * underlying vnode. A locked vnode or NULL is returned. 851 */ 852 struct vnode * 853 vnode_pager_lock(vm_object_t object) 854 { 855 struct vnode *vp = NULL; 856 vm_object_t lobject; 857 vm_object_t tobject; 858 int error; 859 860 if (object == NULL) 861 return(NULL); 862 863 ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); 864 lobject = object; 865 866 while (lobject->type != OBJT_VNODE) { 867 if (lobject->flags & OBJ_DEAD) 868 break; 869 tobject = lobject->backing_object; 870 if (tobject == NULL) 871 break; 872 vm_object_hold(tobject); 873 if (tobject == lobject->backing_object) { 874 if (lobject != object) { 875 vm_object_lock_swap(); 876 vm_object_drop(lobject); 877 } 878 lobject = tobject; 879 } else { 880 vm_object_drop(tobject); 881 } 882 } 883 while (lobject->type == OBJT_VNODE && 884 (lobject->flags & OBJ_DEAD) == 0) { 885 /* 886 * Extract the vp 887 */ 888 vp = lobject->handle; 889 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 890 if (error == 0) { 891 if (lobject->handle == vp) 892 break; 893 vput(vp); 894 } else { 895 kprintf("vnode_pager_lock: vp %p error %d " 896 "lockstatus %d, retrying\n", 897 vp, error, 898 lockstatus(&vp->v_lock, curthread)); 899 tsleep(object->handle, 0, "vnpgrl", hz); 900 } 901 vp = NULL; 902 } 903 if (lobject != object) 904 vm_object_drop(lobject); 905 return (vp); 906 } 907