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