1 /* 2 * Copyright (c) 1990 University of Utah. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * Copyright (c) 1993, 1994 John S. Dyson 6 * Copyright (c) 1995, David Greenman 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 41 * $FreeBSD: src/sys/vm/vnode_pager.c,v 1.116.2.7 2002/12/31 09:34:51 dillon Exp $ 42 * $DragonFly: src/sys/vm/vnode_pager.c,v 1.43 2008/06/19 23:27:39 dillon Exp $ 43 */ 44 45 /* 46 * Page to/from files (vnodes). 47 */ 48 49 /* 50 * TODO: 51 * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will 52 * greatly re-simplify the vnode_pager. 53 */ 54 55 #include <sys/param.h> 56 #include <sys/systm.h> 57 #include <sys/kernel.h> 58 #include <sys/proc.h> 59 #include <sys/vnode.h> 60 #include <sys/mount.h> 61 #include <sys/buf.h> 62 #include <sys/vmmeter.h> 63 #include <sys/conf.h> 64 65 #include <cpu/lwbuf.h> 66 67 #include <vm/vm.h> 68 #include <vm/vm_object.h> 69 #include <vm/vm_page.h> 70 #include <vm/vm_pager.h> 71 #include <vm/vm_map.h> 72 #include <vm/vnode_pager.h> 73 #include <vm/swap_pager.h> 74 #include <vm/vm_extern.h> 75 76 #include <sys/thread2.h> 77 #include <vm/vm_page2.h> 78 79 static void vnode_pager_dealloc (vm_object_t); 80 static int vnode_pager_getpage (vm_object_t, vm_page_t *, int); 81 static void vnode_pager_putpages (vm_object_t, vm_page_t *, int, boolean_t, int *); 82 static boolean_t vnode_pager_haspage (vm_object_t, vm_pindex_t); 83 84 struct pagerops vnodepagerops = { 85 vnode_pager_dealloc, 86 vnode_pager_getpage, 87 vnode_pager_putpages, 88 vnode_pager_haspage 89 }; 90 91 static struct krate vbadrate = { 1 }; 92 static struct krate vresrate = { 1 }; 93 94 int vnode_pbuf_freecnt = -1; /* start out unlimited */ 95 96 /* 97 * Allocate a VM object for a vnode, typically a regular file vnode. 98 * 99 * Some additional information is required to generate a properly sized 100 * object which covers the entire buffer cache buffer straddling the file 101 * EOF. Userland does not see the extra pages as the VM fault code tests 102 * against v_filesize. 103 */ 104 vm_object_t 105 vnode_pager_alloc(void *handle, off_t length, vm_prot_t prot, off_t offset, 106 int blksize, int boff) 107 { 108 vm_object_t object; 109 struct vnode *vp; 110 off_t loffset; 111 vm_pindex_t lsize; 112 113 /* 114 * Pageout to vnode, no can do yet. 115 */ 116 if (handle == NULL) 117 return (NULL); 118 119 /* 120 * XXX hack - This initialization should be put somewhere else. 121 */ 122 if (vnode_pbuf_freecnt < 0) { 123 vnode_pbuf_freecnt = nswbuf / 2 + 1; 124 } 125 126 vp = (struct vnode *) handle; 127 128 /* 129 * Prevent race condition when allocating the object. This 130 * can happen with NFS vnodes since the nfsnode isn't locked. 131 */ 132 while (vp->v_flag & VOLOCK) { 133 vsetflags(vp, VOWANT); 134 tsleep(vp, 0, "vnpobj", 0); 135 } 136 vsetflags(vp, VOLOCK); 137 138 /* 139 * If the object is being terminated, wait for it to 140 * go away. 141 */ 142 while (((object = vp->v_object) != NULL) && 143 (object->flags & OBJ_DEAD)) { 144 vm_object_dead_sleep(object, "vadead"); 145 } 146 147 if (vp->v_sysref.refcnt <= 0) 148 panic("vnode_pager_alloc: no vnode reference"); 149 150 /* 151 * Round up to the *next* block, then destroy the buffers in question. 152 * Since we are only removing some of the buffers we must rely on the 153 * scan count to determine whether a loop is necessary. 154 * 155 * Destroy any pages beyond the last buffer. 156 */ 157 if (boff < 0) 158 boff = (int)(length % blksize); 159 if (boff) 160 loffset = length + (blksize - boff); 161 else 162 loffset = length; 163 lsize = OFF_TO_IDX(round_page64(loffset)); 164 165 if (object == NULL) { 166 /* 167 * And an object of the appropriate size 168 */ 169 object = vm_object_allocate(OBJT_VNODE, lsize); 170 object->flags = 0; 171 object->handle = handle; 172 vp->v_object = object; 173 vp->v_filesize = length; 174 if (vp->v_mount && (vp->v_mount->mnt_kern_flag & MNTK_NOMSYNC)) 175 object->flags |= OBJ_NOMSYNC; 176 } else { 177 object->ref_count++; 178 if (object->size != lsize) { 179 kprintf("vnode_pager_alloc: Warning, objsize " 180 "mismatch %jd/%jd vp=%p obj=%p\n", 181 (intmax_t)object->size, 182 (intmax_t)lsize, 183 vp, object); 184 } 185 if (vp->v_filesize != length) { 186 kprintf("vnode_pager_alloc: Warning, filesize " 187 "mismatch %jd/%jd vp=%p obj=%p\n", 188 (intmax_t)vp->v_filesize, 189 (intmax_t)length, 190 vp, object); 191 } 192 } 193 vref(vp); 194 195 vclrflags(vp, VOLOCK); 196 if (vp->v_flag & VOWANT) { 197 vclrflags(vp, VOWANT); 198 wakeup(vp); 199 } 200 return (object); 201 } 202 203 /* 204 * Add a ref to a vnode's existing VM object, return the object or 205 * NULL if the vnode did not have one. This does not create the 206 * object (we can't since we don't know what the proper blocksize/boff 207 * is to match the VFS's use of the buffer cache). 208 */ 209 vm_object_t 210 vnode_pager_reference(struct vnode *vp) 211 { 212 vm_object_t object; 213 214 /* 215 * Prevent race condition when allocating the object. This 216 * can happen with NFS vnodes since the nfsnode isn't locked. 217 */ 218 while (vp->v_flag & VOLOCK) { 219 vsetflags(vp, VOWANT); 220 tsleep(vp, 0, "vnpobj", 0); 221 } 222 vsetflags(vp, VOLOCK); 223 224 /* 225 * Prevent race conditions against deallocation of the VM 226 * object. 227 */ 228 while (((object = vp->v_object) != NULL) && 229 (object->flags & OBJ_DEAD)) { 230 vm_object_dead_sleep(object, "vadead"); 231 } 232 233 /* 234 * The object is expected to exist, the caller will handle 235 * NULL returns if it does not. 236 */ 237 if (object) { 238 object->ref_count++; 239 vref(vp); 240 } 241 242 vclrflags(vp, VOLOCK); 243 if (vp->v_flag & VOWANT) { 244 vclrflags(vp, VOWANT); 245 wakeup(vp); 246 } 247 return (object); 248 } 249 250 static void 251 vnode_pager_dealloc(vm_object_t object) 252 { 253 struct vnode *vp = object->handle; 254 255 if (vp == NULL) 256 panic("vnode_pager_dealloc: pager already dealloced"); 257 258 vm_object_pip_wait(object, "vnpdea"); 259 260 object->handle = NULL; 261 object->type = OBJT_DEAD; 262 vp->v_object = NULL; 263 vp->v_filesize = NOOFFSET; 264 vclrflags(vp, VTEXT | VOBJBUF); 265 swap_pager_freespace_all(object); 266 } 267 268 /* 269 * Return whether the vnode pager has the requested page. Return the 270 * number of disk-contiguous pages before and after the requested page, 271 * not including the requested page. 272 */ 273 static boolean_t 274 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex) 275 { 276 struct vnode *vp = object->handle; 277 off_t loffset; 278 off_t doffset; 279 int voff; 280 int bsize; 281 int error; 282 283 /* 284 * If no vp or vp is doomed or marked transparent to VM, we do not 285 * have the page. 286 */ 287 if ((vp == NULL) || (vp->v_flag & VRECLAIMED)) 288 return FALSE; 289 290 /* 291 * If filesystem no longer mounted or offset beyond end of file we do 292 * not have the page. 293 */ 294 loffset = IDX_TO_OFF(pindex); 295 296 if (vp->v_mount == NULL || loffset >= vp->v_filesize) 297 return FALSE; 298 299 bsize = vp->v_mount->mnt_stat.f_iosize; 300 voff = loffset % bsize; 301 302 /* 303 * XXX 304 * 305 * BMAP returns byte counts before and after, where after 306 * is inclusive of the base page. haspage must return page 307 * counts before and after where after does not include the 308 * base page. 309 * 310 * BMAP is allowed to return a *after of 0 for backwards 311 * compatibility. The base page is still considered valid if 312 * no error is returned. 313 */ 314 error = VOP_BMAP(vp, loffset - voff, &doffset, NULL, NULL, 0); 315 if (error) 316 return TRUE; 317 if (doffset == NOOFFSET) 318 return FALSE; 319 return TRUE; 320 } 321 322 /* 323 * Lets the VM system know about a change in size for a file. 324 * We adjust our own internal size and flush any cached pages in 325 * the associated object that are affected by the size change. 326 * 327 * NOTE: This routine may be invoked as a result of a pager put 328 * operation (possibly at object termination time), so we must be careful. 329 * 330 * NOTE: vp->v_filesize is initialized to NOOFFSET (-1), be sure that 331 * we do not blow up on the case. nsize will always be >= 0, however. 332 */ 333 void 334 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize) 335 { 336 vm_pindex_t nobjsize; 337 vm_pindex_t oobjsize; 338 vm_object_t object = vp->v_object; 339 340 if (object == NULL) 341 return; 342 343 /* 344 * Hasn't changed size 345 */ 346 if (nsize == vp->v_filesize) 347 return; 348 349 lwkt_gettoken(&vm_token); 350 351 /* 352 * Has changed size. Adjust the VM object's size and v_filesize 353 * before we start scanning pages to prevent new pages from being 354 * allocated during the scan. 355 */ 356 nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); 357 oobjsize = object->size; 358 object->size = nobjsize; 359 360 /* 361 * File has shrunk. Toss any cached pages beyond the new EOF. 362 */ 363 if (nsize < vp->v_filesize) { 364 vp->v_filesize = nsize; 365 if (nobjsize < oobjsize) { 366 vm_object_page_remove(object, nobjsize, oobjsize, 367 FALSE); 368 } 369 /* 370 * This gets rid of garbage at the end of a page that is now 371 * only partially backed by the vnode. Since we are setting 372 * the entire page valid & clean after we are done we have 373 * to be sure that the portion of the page within the file 374 * bounds is already valid. If it isn't then making it 375 * valid would create a corrupt block. 376 */ 377 if (nsize & PAGE_MASK) { 378 vm_offset_t kva; 379 vm_page_t m; 380 381 do { 382 m = vm_page_lookup(object, OFF_TO_IDX(nsize)); 383 } while (m && vm_page_sleep_busy(m, TRUE, "vsetsz")); 384 385 if (m && m->valid) { 386 int base = (int)nsize & PAGE_MASK; 387 int size = PAGE_SIZE - base; 388 struct lwbuf *lwb; 389 390 /* 391 * Clear out partial-page garbage in case 392 * the page has been mapped. 393 * 394 * This is byte aligned. 395 */ 396 vm_page_busy(m); 397 lwb = lwbuf_alloc(m); 398 kva = lwbuf_kva(lwb); 399 bzero((caddr_t)kva + base, size); 400 lwbuf_free(lwb); 401 402 /* 403 * XXX work around SMP data integrity race 404 * by unmapping the page from user processes. 405 * The garbage we just cleared may be mapped 406 * to a user process running on another cpu 407 * and this code is not running through normal 408 * I/O channels which handle SMP issues for 409 * us, so unmap page to synchronize all cpus. 410 * 411 * XXX should vm_pager_unmap_page() have 412 * dealt with this? 413 */ 414 vm_page_protect(m, VM_PROT_NONE); 415 416 /* 417 * Clear out partial-page dirty bits. This 418 * has the side effect of setting the valid 419 * bits, but that is ok. There are a bunch 420 * of places in the VM system where we expected 421 * m->dirty == VM_PAGE_BITS_ALL. The file EOF 422 * case is one of them. If the page is still 423 * partially dirty, make it fully dirty. 424 * 425 * NOTE: We do not clear out the valid 426 * bits. This would prevent bogus_page 427 * replacement from working properly. 428 * 429 * NOTE: We do not want to clear the dirty 430 * bit for a partial DEV_BSIZE'd truncation! 431 * This is DEV_BSIZE aligned! 432 */ 433 vm_page_clear_dirty_beg_nonincl(m, base, size); 434 if (m->dirty != 0) 435 m->dirty = VM_PAGE_BITS_ALL; 436 vm_page_wakeup(m); 437 } 438 } 439 } else { 440 vp->v_filesize = nsize; 441 } 442 lwkt_reltoken(&vm_token); 443 } 444 445 /* 446 * Release a page busied for a getpages operation. The page may have become 447 * wired (typically due to being used by the buffer cache) or otherwise been 448 * soft-busied and cannot be freed in that case. A held page can still be 449 * freed. 450 */ 451 void 452 vnode_pager_freepage(vm_page_t m) 453 { 454 if (m->busy || m->wire_count) { 455 vm_page_activate(m); 456 vm_page_wakeup(m); 457 } else { 458 vm_page_free(m); 459 } 460 } 461 462 /* 463 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 464 * implement their own VOP_GETPAGES, their VOP_GETPAGES should call to 465 * vnode_pager_generic_getpages() to implement the previous behaviour. 466 * 467 * All other FS's should use the bypass to get to the local media 468 * backing vp's VOP_GETPAGES. 469 */ 470 static int 471 vnode_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 472 { 473 int rtval; 474 struct vnode *vp; 475 476 vp = object->handle; 477 rtval = VOP_GETPAGES(vp, mpp, PAGE_SIZE, 0, 0, seqaccess); 478 if (rtval == EOPNOTSUPP) 479 panic("vnode_pager: vfs's must implement vop_getpages\n"); 480 return rtval; 481 } 482 483 /* 484 * This is now called from local media FS's to operate against their 485 * own vnodes if they fail to implement VOP_GETPAGES. 486 * 487 * With all the caching local media devices do these days there is really 488 * very little point to attempting to restrict the I/O size to contiguous 489 * blocks on-disk, especially if our caller thinks we need all the specified 490 * pages. Just construct and issue a READ. 491 */ 492 int 493 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *mpp, int bytecount, 494 int reqpage, int seqaccess) 495 { 496 struct iovec aiov; 497 struct uio auio; 498 off_t foff; 499 int error; 500 int count; 501 int i; 502 int ioflags; 503 504 /* 505 * Do not do anything if the vnode is bad. 506 */ 507 if (vp->v_mount == NULL) 508 return VM_PAGER_BAD; 509 510 /* 511 * Calculate the number of pages. Since we are paging in whole 512 * pages, adjust bytecount to be an integral multiple of the page 513 * size. It will be clipped to the file EOF later on. 514 */ 515 bytecount = round_page(bytecount); 516 count = bytecount / PAGE_SIZE; 517 518 /* 519 * We could check m[reqpage]->valid here and shortcut the operation, 520 * but doing so breaks read-ahead. Instead assume that the VM 521 * system has already done at least the check, don't worry about 522 * any races, and issue the VOP_READ to allow read-ahead to function. 523 * 524 * This keeps the pipeline full for I/O bound sequentially scanned 525 * mmap()'s 526 */ 527 /* don't shortcut */ 528 529 /* 530 * Discard pages past the file EOF. If the requested page is past 531 * the file EOF we just leave its valid bits set to 0, the caller 532 * expects to maintain ownership of the requested page. If the 533 * entire range is past file EOF discard everything and generate 534 * a pagein error. 535 */ 536 foff = IDX_TO_OFF(mpp[0]->pindex); 537 if (foff >= vp->v_filesize) { 538 for (i = 0; i < count; i++) { 539 if (i != reqpage) 540 vnode_pager_freepage(mpp[i]); 541 } 542 return VM_PAGER_ERROR; 543 } 544 545 if (foff + bytecount > vp->v_filesize) { 546 bytecount = vp->v_filesize - foff; 547 i = round_page(bytecount) / PAGE_SIZE; 548 while (count > i) { 549 --count; 550 if (count != reqpage) 551 vnode_pager_freepage(mpp[count]); 552 } 553 } 554 555 /* 556 * The size of the transfer is bytecount. bytecount will be an 557 * integral multiple of the page size unless it has been clipped 558 * to the file EOF. The transfer cannot exceed the file EOF. 559 * 560 * When dealing with real devices we must round-up to the device 561 * sector size. 562 */ 563 if (vp->v_type == VBLK || vp->v_type == VCHR) { 564 int secmask = vp->v_rdev->si_bsize_phys - 1; 565 KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); 566 bytecount = (bytecount + secmask) & ~secmask; 567 } 568 569 /* 570 * Severe hack to avoid deadlocks with the buffer cache 571 */ 572 for (i = 0; i < count; ++i) { 573 vm_page_t mt = mpp[i]; 574 575 vm_page_io_start(mt); 576 vm_page_wakeup(mt); 577 } 578 579 /* 580 * Issue the I/O with some read-ahead if bytecount > PAGE_SIZE 581 */ 582 ioflags = IO_VMIO; 583 if (seqaccess) 584 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 585 586 aiov.iov_base = NULL; 587 aiov.iov_len = bytecount; 588 auio.uio_iov = &aiov; 589 auio.uio_iovcnt = 1; 590 auio.uio_offset = foff; 591 auio.uio_segflg = UIO_NOCOPY; 592 auio.uio_rw = UIO_READ; 593 auio.uio_resid = bytecount; 594 auio.uio_td = NULL; 595 mycpu->gd_cnt.v_vnodein++; 596 mycpu->gd_cnt.v_vnodepgsin += count; 597 598 error = VOP_READ(vp, &auio, ioflags, proc0.p_ucred); 599 600 /* 601 * Severe hack to avoid deadlocks with the buffer cache 602 */ 603 lwkt_gettoken(&vm_token); 604 for (i = 0; i < count; ++i) { 605 vm_page_t mt = mpp[i]; 606 607 while (vm_page_sleep_busy(mt, FALSE, "getpgs")) 608 ; 609 vm_page_busy(mt); 610 vm_page_io_finish(mt); 611 } 612 lwkt_reltoken(&vm_token); 613 614 /* 615 * Calculate the actual number of bytes read and clean up the 616 * page list. 617 */ 618 bytecount -= auio.uio_resid; 619 620 for (i = 0; i < count; ++i) { 621 vm_page_t mt = mpp[i]; 622 623 if (i != reqpage) { 624 if (error == 0 && mt->valid) { 625 if (mt->flags & PG_WANTED) 626 vm_page_activate(mt); 627 else 628 vm_page_deactivate(mt); 629 vm_page_wakeup(mt); 630 } else { 631 vnode_pager_freepage(mt); 632 } 633 } else if (mt->valid == 0) { 634 if (error == 0) { 635 kprintf("page failed but no I/O error page %p object %p pindex %d\n", mt, mt->object, (int) mt->pindex); 636 /* whoops, something happened */ 637 error = EINVAL; 638 } 639 } else if (mt->valid != VM_PAGE_BITS_ALL) { 640 /* 641 * Zero-extend the requested page if necessary (if 642 * the filesystem is using a small block size). 643 */ 644 vm_page_zero_invalid(mt, TRUE); 645 } 646 } 647 if (error) { 648 kprintf("vnode_pager_getpage: I/O read error\n"); 649 } 650 return (error ? VM_PAGER_ERROR : VM_PAGER_OK); 651 } 652 653 /* 654 * EOPNOTSUPP is no longer legal. For local media VFS's that do not 655 * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to 656 * vnode_pager_generic_putpages() to implement the previous behaviour. 657 * 658 * Caller has already cleared the pmap modified bits, if any. 659 * 660 * All other FS's should use the bypass to get to the local media 661 * backing vp's VOP_PUTPAGES. 662 */ 663 static void 664 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count, 665 boolean_t sync, int *rtvals) 666 { 667 int rtval; 668 struct vnode *vp; 669 int bytes = count * PAGE_SIZE; 670 671 /* 672 * Force synchronous operation if we are extremely low on memory 673 * to prevent a low-memory deadlock. VOP operations often need to 674 * allocate more memory to initiate the I/O ( i.e. do a BMAP 675 * operation ). The swapper handles the case by limiting the amount 676 * of asynchronous I/O, but that sort of solution doesn't scale well 677 * for the vnode pager without a lot of work. 678 * 679 * Also, the backing vnode's iodone routine may not wake the pageout 680 * daemon up. This should be probably be addressed XXX. 681 */ 682 683 if ((vmstats.v_free_count + vmstats.v_cache_count) < vmstats.v_pageout_free_min) 684 sync |= OBJPC_SYNC; 685 686 /* 687 * Call device-specific putpages function 688 */ 689 vp = object->handle; 690 rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); 691 if (rtval == EOPNOTSUPP) { 692 kprintf("vnode_pager: *** WARNING *** stale FS putpages\n"); 693 rtval = vnode_pager_generic_putpages( vp, m, bytes, sync, rtvals); 694 } 695 } 696 697 698 /* 699 * This is now called from local media FS's to operate against their 700 * own vnodes if they fail to implement VOP_PUTPAGES. 701 * 702 * This is typically called indirectly via the pageout daemon and 703 * clustering has already typically occured, so in general we ask the 704 * underlying filesystem to write the data out asynchronously rather 705 * then delayed. 706 */ 707 int 708 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *m, int bytecount, 709 int flags, int *rtvals) 710 { 711 int i; 712 vm_object_t object; 713 int maxsize, ncount, count; 714 vm_ooffset_t poffset; 715 struct uio auio; 716 struct iovec aiov; 717 int error; 718 int ioflags; 719 720 object = vp->v_object; 721 count = bytecount / PAGE_SIZE; 722 723 for (i = 0; i < count; i++) 724 rtvals[i] = VM_PAGER_AGAIN; 725 726 if ((int) m[0]->pindex < 0) { 727 kprintf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", 728 (long)m[0]->pindex, m[0]->dirty); 729 rtvals[0] = VM_PAGER_BAD; 730 return VM_PAGER_BAD; 731 } 732 733 maxsize = count * PAGE_SIZE; 734 ncount = count; 735 736 poffset = IDX_TO_OFF(m[0]->pindex); 737 738 /* 739 * If the page-aligned write is larger then the actual file we 740 * have to invalidate pages occuring beyond the file EOF. 741 * 742 * If the file EOF resides in the middle of a page we still clear 743 * all of that page's dirty bits later on. If we didn't it would 744 * endlessly re-write. 745 * 746 * We do not under any circumstances truncate the valid bits, as 747 * this will screw up bogus page replacement. 748 * 749 * The caller has already read-protected the pages. The VFS must 750 * use the buffer cache to wrap the pages. The pages might not 751 * be immediately flushed by the buffer cache but once under its 752 * control the pages themselves can wind up being marked clean 753 * and their covering buffer cache buffer can be marked dirty. 754 */ 755 if (poffset + maxsize > vp->v_filesize) { 756 if (poffset < vp->v_filesize) { 757 maxsize = vp->v_filesize - poffset; 758 ncount = btoc(maxsize); 759 } else { 760 maxsize = 0; 761 ncount = 0; 762 } 763 if (ncount < count) { 764 for (i = ncount; i < count; i++) { 765 rtvals[i] = VM_PAGER_BAD; 766 } 767 } 768 } 769 770 /* 771 * pageouts are already clustered, use IO_ASYNC to force a bawrite() 772 * rather then a bdwrite() to prevent paging I/O from saturating 773 * the buffer cache. Dummy-up the sequential heuristic to cause 774 * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, 775 * the system decides how to cluster. 776 */ 777 ioflags = IO_VMIO; 778 if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) 779 ioflags |= IO_SYNC; 780 else if ((flags & VM_PAGER_CLUSTER_OK) == 0) 781 ioflags |= IO_ASYNC; 782 ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; 783 ioflags |= IO_SEQMAX << IO_SEQSHIFT; 784 785 aiov.iov_base = (caddr_t) 0; 786 aiov.iov_len = maxsize; 787 auio.uio_iov = &aiov; 788 auio.uio_iovcnt = 1; 789 auio.uio_offset = poffset; 790 auio.uio_segflg = UIO_NOCOPY; 791 auio.uio_rw = UIO_WRITE; 792 auio.uio_resid = maxsize; 793 auio.uio_td = NULL; 794 error = VOP_WRITE(vp, &auio, ioflags, proc0.p_ucred); 795 mycpu->gd_cnt.v_vnodeout++; 796 mycpu->gd_cnt.v_vnodepgsout += ncount; 797 798 if (error) { 799 krateprintf(&vbadrate, 800 "vnode_pager_putpages: I/O error %d\n", error); 801 } 802 if (auio.uio_resid) { 803 krateprintf(&vresrate, 804 "vnode_pager_putpages: residual I/O %zd at %lu\n", 805 auio.uio_resid, (u_long)m[0]->pindex); 806 } 807 if (error == 0) { 808 for (i = 0; i < ncount; i++) { 809 rtvals[i] = VM_PAGER_OK; 810 vm_page_undirty(m[i]); 811 } 812 } 813 return rtvals[0]; 814 } 815 816 struct vnode * 817 vnode_pager_lock(vm_object_t object) 818 { 819 struct thread *td = curthread; /* XXX */ 820 int error; 821 822 for (; object != NULL; object = object->backing_object) { 823 if (object->type != OBJT_VNODE) 824 continue; 825 if (object->flags & OBJ_DEAD) 826 return NULL; 827 828 for (;;) { 829 struct vnode *vp = object->handle; 830 error = vget(vp, LK_SHARED | LK_RETRY | LK_CANRECURSE); 831 if (error == 0) { 832 if (object->handle != vp) { 833 vput(vp); 834 continue; 835 } 836 return (vp); 837 } 838 if ((object->flags & OBJ_DEAD) || 839 (object->type != OBJT_VNODE)) { 840 return NULL; 841 } 842 kprintf("vnode_pager_lock: vp %p error %d lockstatus %d, retrying\n", vp, error, lockstatus(&vp->v_lock, td)); 843 tsleep(object->handle, 0, "vnpgrl", hz); 844 } 845 } 846 return NULL; 847 } 848