1 /* 2 * Copyright (c) 1994 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. This work was done expressly for inclusion into FreeBSD. Other use 17 * is allowed if this notation is included. 18 * 5. Modifications may be freely made to this file if the above conditions 19 * are met. 20 * 21 * $Id: vfs_bio.c,v 1.66 1995/10/08 00:06:08 swallace Exp $ 22 */ 23 24 /* 25 * this file contains a new buffer I/O scheme implementing a coherent 26 * VM object and buffer cache scheme. Pains have been taken to make 27 * sure that the performance degradation associated with schemes such 28 * as this is not realized. 29 * 30 * Author: John S. Dyson 31 * Significant help during the development and debugging phases 32 * had been provided by David Greenman, also of the FreeBSD core team. 33 */ 34 35 #define VMIO 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/sysproto.h> 39 #include <sys/kernel.h> 40 #include <sys/proc.h> 41 #include <sys/vnode.h> 42 #include <vm/vm.h> 43 #include <vm/vm_kern.h> 44 #include <vm/vm_pageout.h> 45 #include <vm/vm_page.h> 46 #include <vm/vm_object.h> 47 #include <sys/buf.h> 48 #include <sys/mount.h> 49 #include <sys/malloc.h> 50 #include <sys/resourcevar.h> 51 #include <sys/proc.h> 52 53 #include <miscfs/specfs/specdev.h> 54 55 /* 56 * System initialization 57 */ 58 59 static void vfs_update __P((void)); 60 struct proc *updateproc; 61 62 static struct kproc_desc up_kp = { 63 "update", 64 vfs_update, 65 &updateproc 66 }; 67 SYSINIT_KT(update, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp) 68 69 70 struct buf *buf; /* buffer header pool */ 71 struct swqueue bswlist; 72 73 void vm_hold_free_pages(struct buf * bp, vm_offset_t from, vm_offset_t to); 74 void vm_hold_load_pages(struct buf * bp, vm_offset_t from, vm_offset_t to); 75 void vfs_clean_pages(struct buf * bp); 76 static void vfs_setdirty(struct buf *bp); 77 static __inline struct buf * gbincore(struct vnode * vp, daddr_t blkno); 78 79 int needsbuffer; 80 81 /* 82 * Internal update daemon, process 3 83 * The variable vfs_update_wakeup allows for internal syncs. 84 */ 85 int vfs_update_wakeup; 86 87 88 /* 89 * buffers base kva 90 */ 91 caddr_t buffers_kva; 92 93 /* 94 * bogus page -- for I/O to/from partially complete buffers 95 * this is a temporary solution to the problem, but it is not 96 * really that bad. it would be better to split the buffer 97 * for input in the case of buffers partially already in memory, 98 * but the code is intricate enough already. 99 */ 100 vm_page_t bogus_page; 101 vm_offset_t bogus_offset; 102 103 int bufspace, maxbufspace; 104 105 /* 106 * advisory minimum for size of LRU queue or VMIO queue 107 */ 108 int minbuf; 109 110 struct bufhashhdr bufhashtbl[BUFHSZ], invalhash; 111 struct bqueues bufqueues[BUFFER_QUEUES]; 112 113 /* 114 * Initialize buffer headers and related structures. 115 */ 116 void 117 bufinit() 118 { 119 struct buf *bp; 120 int i; 121 122 TAILQ_INIT(&bswlist); 123 LIST_INIT(&invalhash); 124 125 /* first, make a null hash table */ 126 for (i = 0; i < BUFHSZ; i++) 127 LIST_INIT(&bufhashtbl[i]); 128 129 /* next, make a null set of free lists */ 130 for (i = 0; i < BUFFER_QUEUES; i++) 131 TAILQ_INIT(&bufqueues[i]); 132 133 buffers_kva = (caddr_t) kmem_alloc_pageable(buffer_map, MAXBSIZE * nbuf); 134 /* finally, initialize each buffer header and stick on empty q */ 135 for (i = 0; i < nbuf; i++) { 136 bp = &buf[i]; 137 bzero(bp, sizeof *bp); 138 bp->b_flags = B_INVAL; /* we're just an empty header */ 139 bp->b_dev = NODEV; 140 bp->b_rcred = NOCRED; 141 bp->b_wcred = NOCRED; 142 bp->b_qindex = QUEUE_EMPTY; 143 bp->b_vnbufs.le_next = NOLIST; 144 bp->b_data = buffers_kva + i * MAXBSIZE; 145 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 146 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 147 } 148 /* 149 * maxbufspace is currently calculated to support all filesystem blocks 150 * to be 8K. If you happen to use a 16K filesystem, the size of the buffer 151 * cache is still the same as it would be for 8K filesystems. This 152 * keeps the size of the buffer cache "in check" for big block filesystems. 153 */ 154 minbuf = nbuf / 3; 155 maxbufspace = 2 * (nbuf + 8) * PAGE_SIZE; 156 157 bogus_offset = kmem_alloc_pageable(kernel_map, PAGE_SIZE); 158 bogus_page = vm_page_alloc(kernel_object, 159 bogus_offset - VM_MIN_KERNEL_ADDRESS, VM_ALLOC_NORMAL); 160 161 } 162 163 /* 164 * remove the buffer from the appropriate free list 165 */ 166 void 167 bremfree(struct buf * bp) 168 { 169 int s = splbio(); 170 171 if (bp->b_qindex != QUEUE_NONE) { 172 TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist); 173 bp->b_qindex = QUEUE_NONE; 174 } else { 175 panic("bremfree: removing a buffer when not on a queue"); 176 } 177 splx(s); 178 } 179 180 /* 181 * Get a buffer with the specified data. Look in the cache first. 182 */ 183 int 184 bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred, 185 struct buf ** bpp) 186 { 187 struct buf *bp; 188 189 bp = getblk(vp, blkno, size, 0, 0); 190 *bpp = bp; 191 192 /* if not found in cache, do some I/O */ 193 if ((bp->b_flags & B_CACHE) == 0) { 194 if (curproc != NULL) 195 curproc->p_stats->p_ru.ru_inblock++; 196 bp->b_flags |= B_READ; 197 bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 198 if (bp->b_rcred == NOCRED) { 199 if (cred != NOCRED) 200 crhold(cred); 201 bp->b_rcred = cred; 202 } 203 vfs_busy_pages(bp, 0); 204 VOP_STRATEGY(bp); 205 return (biowait(bp)); 206 } 207 return (0); 208 } 209 210 /* 211 * Operates like bread, but also starts asynchronous I/O on 212 * read-ahead blocks. 213 */ 214 int 215 breadn(struct vnode * vp, daddr_t blkno, int size, 216 daddr_t * rablkno, int *rabsize, 217 int cnt, struct ucred * cred, struct buf ** bpp) 218 { 219 struct buf *bp, *rabp; 220 int i; 221 int rv = 0, readwait = 0; 222 223 *bpp = bp = getblk(vp, blkno, size, 0, 0); 224 225 /* if not found in cache, do some I/O */ 226 if ((bp->b_flags & B_CACHE) == 0) { 227 if (curproc != NULL) 228 curproc->p_stats->p_ru.ru_inblock++; 229 bp->b_flags |= B_READ; 230 bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 231 if (bp->b_rcred == NOCRED) { 232 if (cred != NOCRED) 233 crhold(cred); 234 bp->b_rcred = cred; 235 } 236 vfs_busy_pages(bp, 0); 237 VOP_STRATEGY(bp); 238 ++readwait; 239 } 240 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 241 if (inmem(vp, *rablkno)) 242 continue; 243 rabp = getblk(vp, *rablkno, *rabsize, 0, 0); 244 245 if ((rabp->b_flags & B_CACHE) == 0) { 246 if (curproc != NULL) 247 curproc->p_stats->p_ru.ru_inblock++; 248 rabp->b_flags |= B_READ | B_ASYNC; 249 rabp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 250 if (rabp->b_rcred == NOCRED) { 251 if (cred != NOCRED) 252 crhold(cred); 253 rabp->b_rcred = cred; 254 } 255 vfs_busy_pages(rabp, 0); 256 VOP_STRATEGY(rabp); 257 } else { 258 brelse(rabp); 259 } 260 } 261 262 if (readwait) { 263 rv = biowait(bp); 264 } 265 return (rv); 266 } 267 268 /* 269 * Write, release buffer on completion. (Done by iodone 270 * if async.) 271 */ 272 int 273 bwrite(struct buf * bp) 274 { 275 int oldflags = bp->b_flags; 276 277 if (bp->b_flags & B_INVAL) { 278 brelse(bp); 279 return (0); 280 } 281 if (!(bp->b_flags & B_BUSY)) 282 panic("bwrite: buffer is not busy???"); 283 284 bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI); 285 bp->b_flags |= B_WRITEINPROG; 286 287 if ((oldflags & (B_ASYNC|B_DELWRI)) == (B_ASYNC|B_DELWRI)) { 288 reassignbuf(bp, bp->b_vp); 289 } 290 291 bp->b_vp->v_numoutput++; 292 vfs_busy_pages(bp, 1); 293 if (curproc != NULL) 294 curproc->p_stats->p_ru.ru_oublock++; 295 VOP_STRATEGY(bp); 296 297 if ((oldflags & B_ASYNC) == 0) { 298 int rtval = biowait(bp); 299 300 if (oldflags & B_DELWRI) { 301 reassignbuf(bp, bp->b_vp); 302 } 303 brelse(bp); 304 return (rtval); 305 } 306 return (0); 307 } 308 309 int 310 vn_bwrite(ap) 311 struct vop_bwrite_args *ap; 312 { 313 return (bwrite(ap->a_bp)); 314 } 315 316 /* 317 * Delayed write. (Buffer is marked dirty). 318 */ 319 void 320 bdwrite(struct buf * bp) 321 { 322 323 if ((bp->b_flags & B_BUSY) == 0) { 324 panic("bdwrite: buffer is not busy"); 325 } 326 if (bp->b_flags & B_INVAL) { 327 brelse(bp); 328 return; 329 } 330 if (bp->b_flags & B_TAPE) { 331 bawrite(bp); 332 return; 333 } 334 bp->b_flags &= ~(B_READ|B_RELBUF); 335 if ((bp->b_flags & B_DELWRI) == 0) { 336 bp->b_flags |= B_DONE | B_DELWRI; 337 reassignbuf(bp, bp->b_vp); 338 } 339 340 /* 341 * This bmap keeps the system from needing to do the bmap later, 342 * perhaps when the system is attempting to do a sync. Since it 343 * is likely that the indirect block -- or whatever other datastructure 344 * that the filesystem needs is still in memory now, it is a good 345 * thing to do this. Note also, that if the pageout daemon is 346 * requesting a sync -- there might not be enough memory to do 347 * the bmap then... So, this is important to do. 348 */ 349 if( bp->b_lblkno == bp->b_blkno) { 350 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 351 } 352 353 /* 354 * Set the *dirty* buffer range based upon the VM system dirty pages. 355 */ 356 vfs_setdirty(bp); 357 358 /* 359 * We need to do this here to satisfy the vnode_pager and the 360 * pageout daemon, so that it thinks that the pages have been 361 * "cleaned". Note that since the pages are in a delayed write 362 * buffer -- the VFS layer "will" see that the pages get written 363 * out on the next sync, or perhaps the cluster will be completed. 364 */ 365 vfs_clean_pages(bp); 366 brelse(bp); 367 return; 368 } 369 370 /* 371 * Asynchronous write. 372 * Start output on a buffer, but do not wait for it to complete. 373 * The buffer is released when the output completes. 374 */ 375 void 376 bawrite(struct buf * bp) 377 { 378 bp->b_flags |= B_ASYNC; 379 (void) VOP_BWRITE(bp); 380 } 381 382 /* 383 * Release a buffer. 384 */ 385 void 386 brelse(struct buf * bp) 387 { 388 int s; 389 390 if (bp->b_flags & B_CLUSTER) { 391 relpbuf(bp); 392 return; 393 } 394 /* anyone need a "free" block? */ 395 s = splbio(); 396 397 if (needsbuffer) { 398 needsbuffer = 0; 399 wakeup(&needsbuffer); 400 } 401 402 /* anyone need this block? */ 403 if (bp->b_flags & B_WANTED) { 404 bp->b_flags &= ~(B_WANTED | B_AGE); 405 wakeup(bp); 406 } else if (bp->b_flags & B_VMIO) { 407 bp->b_flags &= ~B_WANTED; 408 wakeup(bp); 409 } 410 if (bp->b_flags & B_LOCKED) 411 bp->b_flags &= ~B_ERROR; 412 413 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR)) || 414 (bp->b_bufsize <= 0)) { 415 bp->b_flags |= B_INVAL; 416 bp->b_flags &= ~(B_DELWRI | B_CACHE); 417 if (((bp->b_flags & B_VMIO) == 0) && bp->b_vp) 418 brelvp(bp); 419 } 420 421 /* 422 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 423 * constituted, so the B_INVAL flag is used to *invalidate* the buffer, 424 * but the VM object is kept around. The B_NOCACHE flag is used to 425 * invalidate the pages in the VM object. 426 */ 427 if (bp->b_flags & B_VMIO) { 428 vm_offset_t foff; 429 vm_object_t obj; 430 int i, resid; 431 vm_page_t m; 432 struct vnode *vp; 433 int iototal = bp->b_bufsize; 434 435 vp = bp->b_vp; 436 if (!vp) 437 panic("brelse: missing vp"); 438 if (!vp->v_mount) 439 panic("brelse: missing mount info"); 440 441 if (bp->b_npages) { 442 obj = (vm_object_t) vp->v_object; 443 foff = trunc_page(vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno); 444 for (i = 0; i < bp->b_npages; i++) { 445 m = bp->b_pages[i]; 446 if (m == bogus_page) { 447 m = vm_page_lookup(obj, foff); 448 if (!m) { 449 panic("brelse: page missing\n"); 450 } 451 bp->b_pages[i] = m; 452 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 453 } 454 resid = (m->offset + PAGE_SIZE) - foff; 455 if (resid > iototal) 456 resid = iototal; 457 if (resid > 0) { 458 /* 459 * Don't invalidate the page if the local machine has already 460 * modified it. This is the lesser of two evils, and should 461 * be fixed. 462 */ 463 if (bp->b_flags & (B_NOCACHE | B_ERROR)) { 464 vm_page_test_dirty(m); 465 if (m->dirty == 0) { 466 vm_page_set_invalid(m, foff, resid); 467 if (m->valid == 0) 468 vm_page_protect(m, VM_PROT_NONE); 469 } 470 } 471 } 472 foff += resid; 473 iototal -= resid; 474 } 475 } 476 477 if (bp->b_flags & (B_INVAL | B_RELBUF)) { 478 for(i = 0; i < bp->b_npages; i++) { 479 m = bp->b_pages[i]; 480 --m->bmapped; 481 if (m->bmapped == 0) { 482 if (m->flags & PG_WANTED) { 483 wakeup(m); 484 m->flags &= ~PG_WANTED; 485 } 486 if ((m->busy == 0) && ((m->flags & PG_BUSY) == 0)) { 487 vm_page_test_dirty(m); 488 /* 489 * if page isn't valid, no sense in keeping it around 490 */ 491 if (m->valid == 0) { 492 vm_page_protect(m, VM_PROT_NONE); 493 vm_page_free(m); 494 /* 495 * if page isn't dirty and hasn't been referenced by 496 * a process, then cache it 497 */ 498 } else if ((m->dirty & m->valid) == 0 && 499 (m->flags & PG_REFERENCED) == 0 && 500 !pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { 501 vm_page_cache(m); 502 /* 503 * otherwise activate it 504 */ 505 } else if ((m->flags & PG_ACTIVE) == 0) { 506 vm_page_activate(m); 507 m->act_count = 0; 508 } 509 } 510 } 511 } 512 bufspace -= bp->b_bufsize; 513 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 514 bp->b_npages = 0; 515 bp->b_bufsize = 0; 516 bp->b_flags &= ~B_VMIO; 517 if (bp->b_vp) 518 brelvp(bp); 519 } 520 } 521 if (bp->b_qindex != QUEUE_NONE) 522 panic("brelse: free buffer onto another queue???"); 523 524 /* enqueue */ 525 /* buffers with no memory */ 526 if (bp->b_bufsize == 0) { 527 bp->b_qindex = QUEUE_EMPTY; 528 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 529 LIST_REMOVE(bp, b_hash); 530 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 531 bp->b_dev = NODEV; 532 /* buffers with junk contents */ 533 } else if (bp->b_flags & (B_ERROR | B_INVAL | B_NOCACHE | B_RELBUF)) { 534 bp->b_qindex = QUEUE_AGE; 535 TAILQ_INSERT_HEAD(&bufqueues[QUEUE_AGE], bp, b_freelist); 536 LIST_REMOVE(bp, b_hash); 537 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 538 bp->b_dev = NODEV; 539 /* buffers that are locked */ 540 } else if (bp->b_flags & B_LOCKED) { 541 bp->b_qindex = QUEUE_LOCKED; 542 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); 543 /* buffers with stale but valid contents */ 544 } else if (bp->b_flags & B_AGE) { 545 bp->b_qindex = QUEUE_AGE; 546 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_AGE], bp, b_freelist); 547 /* buffers with valid and quite potentially reuseable contents */ 548 } else { 549 bp->b_qindex = QUEUE_LRU; 550 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 551 } 552 553 /* unlock */ 554 bp->b_flags &= ~(B_WANTED | B_BUSY | B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 555 splx(s); 556 } 557 558 /* 559 * Check to see if a block is currently memory resident. 560 */ 561 static __inline struct buf * 562 gbincore(struct vnode * vp, daddr_t blkno) 563 { 564 struct buf *bp; 565 struct bufhashhdr *bh; 566 567 bh = BUFHASH(vp, blkno); 568 bp = bh->lh_first; 569 570 /* Search hash chain */ 571 while (bp != NULL) { 572 /* hit */ 573 if (bp->b_vp == vp && bp->b_lblkno == blkno) { 574 break; 575 } 576 bp = bp->b_hash.le_next; 577 } 578 return (bp); 579 } 580 581 /* 582 * this routine implements clustered async writes for 583 * clearing out B_DELWRI buffers... This is much better 584 * than the old way of writing only one buffer at a time. 585 */ 586 void 587 vfs_bio_awrite(struct buf * bp) 588 { 589 int i; 590 daddr_t lblkno = bp->b_lblkno; 591 struct vnode *vp = bp->b_vp; 592 int s; 593 int ncl; 594 struct buf *bpa; 595 596 s = splbio(); 597 if (vp->v_mount && (vp->v_flag & VVMIO) && 598 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 599 int size = vp->v_mount->mnt_stat.f_iosize; 600 int maxcl = MAXPHYS / size; 601 602 for (i = 1; i < maxcl; i++) { 603 if ((bpa = gbincore(vp, lblkno + i)) && 604 ((bpa->b_flags & (B_BUSY | B_DELWRI | B_CLUSTEROK | B_INVAL)) == 605 (B_DELWRI | B_CLUSTEROK)) && 606 (bpa->b_bufsize == size)) { 607 if ((bpa->b_blkno == bpa->b_lblkno) || 608 (bpa->b_blkno != bp->b_blkno + (i * size) / DEV_BSIZE)) 609 break; 610 } else { 611 break; 612 } 613 } 614 ncl = i; 615 /* 616 * this is a possible cluster write 617 */ 618 if (ncl != 1) { 619 bremfree(bp); 620 cluster_wbuild(vp, bp, size, lblkno, ncl, -1); 621 splx(s); 622 return; 623 } 624 } 625 /* 626 * default (old) behavior, writing out only one block 627 */ 628 bremfree(bp); 629 bp->b_flags |= B_BUSY | B_ASYNC; 630 (void) VOP_BWRITE(bp); 631 splx(s); 632 } 633 634 635 /* 636 * Find a buffer header which is available for use. 637 */ 638 static struct buf * 639 getnewbuf(int slpflag, int slptimeo, int doingvmio) 640 { 641 struct buf *bp; 642 int s; 643 int firstbp = 1; 644 645 s = splbio(); 646 start: 647 if (bufspace >= maxbufspace) 648 goto trytofreespace; 649 650 /* can we constitute a new buffer? */ 651 if ((bp = bufqueues[QUEUE_EMPTY].tqh_first)) { 652 if (bp->b_qindex != QUEUE_EMPTY) 653 panic("getnewbuf: inconsistent EMPTY queue"); 654 bremfree(bp); 655 goto fillbuf; 656 } 657 trytofreespace: 658 /* 659 * We keep the file I/O from hogging metadata I/O 660 * This is desirable because file data is cached in the 661 * VM/Buffer cache even if a buffer is freed. 662 */ 663 if ((bp = bufqueues[QUEUE_AGE].tqh_first)) { 664 if (bp->b_qindex != QUEUE_AGE) 665 panic("getnewbuf: inconsistent AGE queue"); 666 } else if ((bp = bufqueues[QUEUE_LRU].tqh_first)) { 667 if (bp->b_qindex != QUEUE_LRU) 668 panic("getnewbuf: inconsistent LRU queue"); 669 } 670 if (!bp) { 671 /* wait for a free buffer of any kind */ 672 needsbuffer = 1; 673 tsleep(&needsbuffer, PRIBIO | slpflag, "newbuf", slptimeo); 674 splx(s); 675 return (0); 676 } 677 678 /* if we are a delayed write, convert to an async write */ 679 if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) { 680 vfs_bio_awrite(bp); 681 if (!slpflag && !slptimeo) { 682 splx(s); 683 return (0); 684 } 685 goto start; 686 } 687 688 if (bp->b_flags & B_WANTED) { 689 bp->b_flags &= ~B_WANTED; 690 wakeup(bp); 691 } 692 bremfree(bp); 693 694 if (bp->b_flags & B_VMIO) { 695 bp->b_flags |= B_RELBUF | B_BUSY | B_DONE; 696 brelse(bp); 697 bremfree(bp); 698 } 699 700 if (bp->b_vp) 701 brelvp(bp); 702 703 /* we are not free, nor do we contain interesting data */ 704 if (bp->b_rcred != NOCRED) 705 crfree(bp->b_rcred); 706 if (bp->b_wcred != NOCRED) 707 crfree(bp->b_wcred); 708 fillbuf: 709 bp->b_flags |= B_BUSY; 710 LIST_REMOVE(bp, b_hash); 711 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 712 splx(s); 713 if (bp->b_bufsize) { 714 allocbuf(bp, 0); 715 } 716 bp->b_flags = B_BUSY; 717 bp->b_dev = NODEV; 718 bp->b_vp = NULL; 719 bp->b_blkno = bp->b_lblkno = 0; 720 bp->b_iodone = 0; 721 bp->b_error = 0; 722 bp->b_resid = 0; 723 bp->b_bcount = 0; 724 bp->b_npages = 0; 725 bp->b_wcred = bp->b_rcred = NOCRED; 726 bp->b_data = buffers_kva + (bp - buf) * MAXBSIZE; 727 bp->b_dirtyoff = bp->b_dirtyend = 0; 728 bp->b_validoff = bp->b_validend = 0; 729 if (bufspace >= maxbufspace) { 730 s = splbio(); 731 bp->b_flags |= B_INVAL; 732 brelse(bp); 733 goto trytofreespace; 734 } 735 return (bp); 736 } 737 738 /* 739 * Check to see if a block is currently memory resident. 740 */ 741 struct buf * 742 incore(struct vnode * vp, daddr_t blkno) 743 { 744 struct buf *bp; 745 struct bufhashhdr *bh; 746 747 int s = splbio(); 748 749 bh = BUFHASH(vp, blkno); 750 bp = bh->lh_first; 751 752 /* Search hash chain */ 753 while (bp != NULL) { 754 /* hit */ 755 if (bp->b_vp == vp && bp->b_lblkno == blkno && 756 (bp->b_flags & B_INVAL) == 0) { 757 break; 758 } 759 bp = bp->b_hash.le_next; 760 } 761 splx(s); 762 return (bp); 763 } 764 765 /* 766 * Returns true if no I/O is needed to access the 767 * associated VM object. This is like incore except 768 * it also hunts around in the VM system for the data. 769 */ 770 771 int 772 inmem(struct vnode * vp, daddr_t blkno) 773 { 774 vm_object_t obj; 775 vm_offset_t off, toff, tinc; 776 vm_page_t m; 777 778 if (incore(vp, blkno)) 779 return 1; 780 if (vp->v_mount == NULL) 781 return 0; 782 if ((vp->v_object == NULL) || (vp->v_flag & VVMIO) == 0) 783 return 0; 784 785 obj = vp->v_object; 786 tinc = PAGE_SIZE; 787 if (tinc > vp->v_mount->mnt_stat.f_iosize) 788 tinc = vp->v_mount->mnt_stat.f_iosize; 789 off = blkno * vp->v_mount->mnt_stat.f_iosize; 790 791 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 792 int mask; 793 794 m = vm_page_lookup(obj, trunc_page(toff + off)); 795 if (!m) 796 return 0; 797 if (vm_page_is_valid(m, toff + off, tinc) == 0) 798 return 0; 799 } 800 return 1; 801 } 802 803 /* 804 * now we set the dirty range for the buffer -- 805 * for NFS -- if the file is mapped and pages have 806 * been written to, let it know. We want the 807 * entire range of the buffer to be marked dirty if 808 * any of the pages have been written to for consistancy 809 * with the b_validoff, b_validend set in the nfs write 810 * code, and used by the nfs read code. 811 */ 812 static void 813 vfs_setdirty(struct buf *bp) { 814 int i; 815 vm_object_t object; 816 vm_offset_t boffset, offset; 817 /* 818 * We qualify the scan for modified pages on whether the 819 * object has been flushed yet. The OBJ_WRITEABLE flag 820 * is not cleared simply by protecting pages off. 821 */ 822 if ((bp->b_flags & B_VMIO) && 823 ((object = bp->b_pages[0]->object)->flags & OBJ_WRITEABLE)) { 824 /* 825 * test the pages to see if they have been modified directly 826 * by users through the VM system. 827 */ 828 for (i = 0; i < bp->b_npages; i++) 829 vm_page_test_dirty(bp->b_pages[i]); 830 831 /* 832 * scan forwards for the first page modified 833 */ 834 for (i = 0; i < bp->b_npages; i++) { 835 if (bp->b_pages[i]->dirty) { 836 break; 837 } 838 } 839 boffset = i * PAGE_SIZE; 840 if (boffset < bp->b_dirtyoff) { 841 bp->b_dirtyoff = boffset; 842 } 843 844 /* 845 * scan backwards for the last page modified 846 */ 847 for (i = bp->b_npages - 1; i >= 0; --i) { 848 if (bp->b_pages[i]->dirty) { 849 break; 850 } 851 } 852 boffset = (i + 1) * PAGE_SIZE; 853 offset = boffset + bp->b_pages[0]->offset; 854 if (offset >= object->size) { 855 boffset = object->size - bp->b_pages[0]->offset; 856 } 857 if (bp->b_dirtyend < boffset) { 858 bp->b_dirtyend = boffset; 859 } 860 } 861 } 862 863 /* 864 * Get a block given a specified block and offset into a file/device. 865 */ 866 struct buf * 867 getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo) 868 { 869 struct buf *bp; 870 int s; 871 struct bufhashhdr *bh; 872 vm_offset_t off; 873 int nleft; 874 875 s = splbio(); 876 loop: 877 if (bp = gbincore(vp, blkno)) { 878 if (bp->b_flags & (B_BUSY|B_INVAL)) { 879 bp->b_flags |= B_WANTED; 880 if (!tsleep(bp, PRIBIO | slpflag, "getblk", slptimeo)) 881 goto loop; 882 883 splx(s); 884 return (struct buf *) NULL; 885 } 886 bp->b_flags |= B_BUSY | B_CACHE; 887 bremfree(bp); 888 889 /* 890 * check for size inconsistancies (note that they shouldn't happen 891 * but do when filesystems don't handle the size changes correctly.) 892 * We are conservative on metadata and don't just extend the buffer 893 * but write and re-constitute it. 894 */ 895 if (bp->b_bcount != size) { 896 if (bp->b_flags & B_VMIO) { 897 allocbuf(bp, size); 898 } else { 899 bp->b_flags |= B_NOCACHE; 900 VOP_BWRITE(bp); 901 goto loop; 902 } 903 } 904 /* 905 * make sure that all pages in the buffer are valid, if they 906 * aren't, clear the cache flag. 907 * ASSUMPTION: 908 * if the buffer is greater than 1 page in size, it is assumed 909 * that the buffer address starts on a page boundary... 910 */ 911 if (bp->b_flags & B_VMIO) { 912 int szleft, i; 913 szleft = size; 914 for (i=0;i<bp->b_npages;i++) { 915 if (szleft > PAGE_SIZE) { 916 if ((bp->b_pages[i]->valid & VM_PAGE_BITS_ALL) != 917 VM_PAGE_BITS_ALL) { 918 bp->b_flags &= ~(B_CACHE|B_DONE); 919 break; 920 } 921 szleft -= PAGE_SIZE; 922 } else { 923 if (!vm_page_is_valid(bp->b_pages[i], 924 (((vm_offset_t) bp->b_data) & PAGE_MASK), 925 szleft)) { 926 bp->b_flags &= ~(B_CACHE|B_DONE); 927 break; 928 } 929 szleft = 0; 930 } 931 } 932 } 933 splx(s); 934 return (bp); 935 } else { 936 vm_object_t obj; 937 int doingvmio; 938 939 if ((obj = vp->v_object) && (vp->v_flag & VVMIO)) { 940 doingvmio = 1; 941 } else { 942 doingvmio = 0; 943 } 944 if ((bp = getnewbuf(slpflag, slptimeo, doingvmio)) == 0) { 945 if (slpflag || slptimeo) 946 return NULL; 947 goto loop; 948 } 949 950 /* 951 * This code is used to make sure that a buffer is not 952 * created while the getnewbuf routine is blocked. 953 * Normally the vnode is locked so this isn't a problem. 954 * VBLK type I/O requests, however, don't lock the vnode. 955 */ 956 if (!VOP_ISLOCKED(vp) && gbincore(vp, blkno)) { 957 bp->b_flags |= B_INVAL; 958 brelse(bp); 959 goto loop; 960 } 961 962 /* 963 * Insert the buffer into the hash, so that it can 964 * be found by incore. 965 */ 966 bp->b_blkno = bp->b_lblkno = blkno; 967 bgetvp(vp, bp); 968 LIST_REMOVE(bp, b_hash); 969 bh = BUFHASH(vp, blkno); 970 LIST_INSERT_HEAD(bh, bp, b_hash); 971 972 if (doingvmio) { 973 bp->b_flags |= (B_VMIO | B_CACHE); 974 #if defined(VFS_BIO_DEBUG) 975 if (vp->v_type != VREG) 976 printf("getblk: vmioing file type %d???\n", vp->v_type); 977 #endif 978 } else { 979 bp->b_flags &= ~B_VMIO; 980 } 981 splx(s); 982 983 allocbuf(bp, size); 984 return (bp); 985 } 986 } 987 988 /* 989 * Get an empty, disassociated buffer of given size. 990 */ 991 struct buf * 992 geteblk(int size) 993 { 994 struct buf *bp; 995 996 while ((bp = getnewbuf(0, 0, 0)) == 0); 997 allocbuf(bp, size); 998 bp->b_flags |= B_INVAL; 999 return (bp); 1000 } 1001 1002 /* 1003 * This code constitutes the buffer memory from either anonymous system 1004 * memory (in the case of non-VMIO operations) or from an associated 1005 * VM object (in the case of VMIO operations). 1006 * 1007 * Note that this code is tricky, and has many complications to resolve 1008 * deadlock or inconsistant data situations. Tread lightly!!! 1009 * 1010 * Modify the length of a buffer's underlying buffer storage without 1011 * destroying information (unless, of course the buffer is shrinking). 1012 */ 1013 int 1014 allocbuf(struct buf * bp, int size) 1015 { 1016 1017 int s; 1018 int newbsize, mbsize; 1019 int i; 1020 1021 if (!(bp->b_flags & B_BUSY)) 1022 panic("allocbuf: buffer not busy"); 1023 1024 if ((bp->b_flags & B_VMIO) == 0) { 1025 /* 1026 * Just get anonymous memory from the kernel 1027 */ 1028 mbsize = ((size + DEV_BSIZE - 1) / DEV_BSIZE) * DEV_BSIZE; 1029 newbsize = round_page(size); 1030 1031 if (newbsize < bp->b_bufsize) { 1032 vm_hold_free_pages( 1033 bp, 1034 (vm_offset_t) bp->b_data + newbsize, 1035 (vm_offset_t) bp->b_data + bp->b_bufsize); 1036 } else if (newbsize > bp->b_bufsize) { 1037 vm_hold_load_pages( 1038 bp, 1039 (vm_offset_t) bp->b_data + bp->b_bufsize, 1040 (vm_offset_t) bp->b_data + newbsize); 1041 } 1042 } else { 1043 vm_page_t m; 1044 int desiredpages; 1045 1046 newbsize = ((size + DEV_BSIZE - 1) / DEV_BSIZE) * DEV_BSIZE; 1047 desiredpages = round_page(newbsize) / PAGE_SIZE; 1048 1049 if (newbsize < bp->b_bufsize) { 1050 if (desiredpages < bp->b_npages) { 1051 pmap_qremove((vm_offset_t) trunc_page(bp->b_data) + 1052 desiredpages * PAGE_SIZE, (bp->b_npages - desiredpages)); 1053 for (i = desiredpages; i < bp->b_npages; i++) { 1054 m = bp->b_pages[i]; 1055 s = splhigh(); 1056 while ((m->flags & PG_BUSY) || (m->busy != 0)) { 1057 m->flags |= PG_WANTED; 1058 tsleep(m, PVM, "biodep", 0); 1059 } 1060 splx(s); 1061 1062 if (m->bmapped == 0) { 1063 printf("allocbuf: bmapped is zero for page %d\n", i); 1064 panic("allocbuf: error"); 1065 } 1066 --m->bmapped; 1067 if (m->bmapped == 0) { 1068 vm_page_protect(m, VM_PROT_NONE); 1069 vm_page_free(m); 1070 } 1071 bp->b_pages[i] = NULL; 1072 } 1073 bp->b_npages = desiredpages; 1074 } 1075 } else if (newbsize > bp->b_bufsize) { 1076 vm_object_t obj; 1077 vm_offset_t tinc, off, toff, objoff; 1078 int pageindex, curbpnpages; 1079 struct vnode *vp; 1080 int bsize; 1081 1082 vp = bp->b_vp; 1083 bsize = vp->v_mount->mnt_stat.f_iosize; 1084 1085 if (bp->b_npages < desiredpages) { 1086 obj = vp->v_object; 1087 tinc = PAGE_SIZE; 1088 if (tinc > bsize) 1089 tinc = bsize; 1090 off = bp->b_lblkno * bsize; 1091 doretry: 1092 curbpnpages = bp->b_npages; 1093 bp->b_flags |= B_CACHE; 1094 for (toff = 0; toff < newbsize; toff += tinc) { 1095 int mask; 1096 int bytesinpage; 1097 1098 pageindex = toff / PAGE_SIZE; 1099 objoff = trunc_page(toff + off); 1100 if (pageindex < curbpnpages) { 1101 int pb; 1102 1103 m = bp->b_pages[pageindex]; 1104 if (m->offset != objoff) 1105 panic("allocbuf: page changed offset??!!!?"); 1106 bytesinpage = tinc; 1107 if (tinc > (newbsize - toff)) 1108 bytesinpage = newbsize - toff; 1109 if (!vm_page_is_valid(m, toff + off, bytesinpage)) { 1110 bp->b_flags &= ~B_CACHE; 1111 } 1112 if ((m->flags & PG_ACTIVE) == 0) { 1113 vm_page_activate(m); 1114 m->act_count = 0; 1115 } 1116 continue; 1117 } 1118 m = vm_page_lookup(obj, objoff); 1119 if (!m) { 1120 m = vm_page_alloc(obj, objoff, VM_ALLOC_NORMAL); 1121 if (!m) { 1122 int j; 1123 1124 for (j = bp->b_npages; j < pageindex; j++) { 1125 PAGE_WAKEUP(bp->b_pages[j]); 1126 } 1127 VM_WAIT; 1128 goto doretry; 1129 } 1130 vm_page_activate(m); 1131 m->act_count = 0; 1132 m->valid = 0; 1133 bp->b_flags &= ~B_CACHE; 1134 } else if (m->flags & PG_BUSY) { 1135 int j; 1136 1137 for (j = bp->b_npages; j < pageindex; j++) { 1138 PAGE_WAKEUP(bp->b_pages[j]); 1139 } 1140 1141 s = splbio(); 1142 m->flags |= PG_WANTED; 1143 tsleep(m, PRIBIO, "pgtblk", 0); 1144 splx(s); 1145 1146 goto doretry; 1147 } else { 1148 int pb; 1149 if ((curproc != pageproc) && 1150 (m->flags & PG_CACHE) && 1151 (cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 1152 pagedaemon_wakeup(); 1153 } 1154 bytesinpage = tinc; 1155 if (tinc > (newbsize - toff)) 1156 bytesinpage = newbsize - toff; 1157 if (!vm_page_is_valid(m, toff + off, bytesinpage)) { 1158 bp->b_flags &= ~B_CACHE; 1159 } 1160 if ((m->flags & PG_ACTIVE) == 0) { 1161 vm_page_activate(m); 1162 m->act_count = 0; 1163 } 1164 m->flags |= PG_BUSY; 1165 } 1166 bp->b_pages[pageindex] = m; 1167 curbpnpages = pageindex + 1; 1168 } 1169 for (i = bp->b_npages; i < curbpnpages; i++) { 1170 m = bp->b_pages[i]; 1171 m->bmapped++; 1172 PAGE_WAKEUP(m); 1173 } 1174 bp->b_npages = curbpnpages; 1175 bp->b_data = buffers_kva + (bp - buf) * MAXBSIZE; 1176 pmap_qenter((vm_offset_t) bp->b_data, bp->b_pages, bp->b_npages); 1177 bp->b_data += off % PAGE_SIZE; 1178 } 1179 } 1180 } 1181 bufspace += (newbsize - bp->b_bufsize); 1182 bp->b_bufsize = newbsize; 1183 bp->b_bcount = size; 1184 return 1; 1185 } 1186 1187 /* 1188 * Wait for buffer I/O completion, returning error status. 1189 */ 1190 int 1191 biowait(register struct buf * bp) 1192 { 1193 int s; 1194 1195 s = splbio(); 1196 while ((bp->b_flags & B_DONE) == 0) 1197 tsleep(bp, PRIBIO, "biowait", 0); 1198 splx(s); 1199 if (bp->b_flags & B_EINTR) { 1200 bp->b_flags &= ~B_EINTR; 1201 return (EINTR); 1202 } 1203 if (bp->b_flags & B_ERROR) { 1204 return (bp->b_error ? bp->b_error : EIO); 1205 } else { 1206 return (0); 1207 } 1208 } 1209 1210 /* 1211 * Finish I/O on a buffer, calling an optional function. 1212 * This is usually called from interrupt level, so process blocking 1213 * is not *a good idea*. 1214 */ 1215 void 1216 biodone(register struct buf * bp) 1217 { 1218 int s; 1219 1220 s = splbio(); 1221 if (!(bp->b_flags & B_BUSY)) 1222 panic("biodone: buffer not busy"); 1223 1224 if (bp->b_flags & B_DONE) { 1225 splx(s); 1226 printf("biodone: buffer already done\n"); 1227 return; 1228 } 1229 bp->b_flags |= B_DONE; 1230 1231 if ((bp->b_flags & B_READ) == 0) { 1232 struct vnode *vp = bp->b_vp; 1233 vwakeup(bp); 1234 } 1235 #ifdef BOUNCE_BUFFERS 1236 if (bp->b_flags & B_BOUNCE) 1237 vm_bounce_free(bp); 1238 #endif 1239 1240 /* call optional completion function if requested */ 1241 if (bp->b_flags & B_CALL) { 1242 bp->b_flags &= ~B_CALL; 1243 (*bp->b_iodone) (bp); 1244 splx(s); 1245 return; 1246 } 1247 if (bp->b_flags & B_VMIO) { 1248 int i, resid; 1249 vm_offset_t foff; 1250 vm_page_t m; 1251 vm_object_t obj; 1252 int iosize; 1253 struct vnode *vp = bp->b_vp; 1254 1255 foff = vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 1256 obj = vp->v_object; 1257 if (!obj) { 1258 panic("biodone: no object"); 1259 } 1260 #if defined(VFS_BIO_DEBUG) 1261 if (obj->paging_in_progress < bp->b_npages) { 1262 printf("biodone: paging in progress(%d) < bp->b_npages(%d)\n", 1263 obj->paging_in_progress, bp->b_npages); 1264 } 1265 #endif 1266 iosize = bp->b_bufsize; 1267 for (i = 0; i < bp->b_npages; i++) { 1268 int bogusflag = 0; 1269 m = bp->b_pages[i]; 1270 if (m == bogus_page) { 1271 bogusflag = 1; 1272 m = vm_page_lookup(obj, foff); 1273 if (!m) { 1274 #if defined(VFS_BIO_DEBUG) 1275 printf("biodone: page disappeared\n"); 1276 #endif 1277 --obj->paging_in_progress; 1278 continue; 1279 } 1280 bp->b_pages[i] = m; 1281 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 1282 } 1283 #if defined(VFS_BIO_DEBUG) 1284 if (trunc_page(foff) != m->offset) { 1285 printf("biodone: foff(%d)/m->offset(%d) mismatch\n", foff, m->offset); 1286 } 1287 #endif 1288 resid = (m->offset + PAGE_SIZE) - foff; 1289 if (resid > iosize) 1290 resid = iosize; 1291 /* 1292 * In the write case, the valid and clean bits are 1293 * already changed correctly, so we only need to do this 1294 * here in the read case. 1295 */ 1296 if ((bp->b_flags & B_READ) && !bogusflag && resid > 0) { 1297 vm_page_set_validclean(m, foff & (PAGE_SIZE-1), resid); 1298 } 1299 1300 /* 1301 * when debugging new filesystems or buffer I/O methods, this 1302 * is the most common error that pops up. if you see this, you 1303 * have not set the page busy flag correctly!!! 1304 */ 1305 if (m->busy == 0) { 1306 printf("biodone: page busy < 0, " 1307 "off: %ld, foff: %ld, " 1308 "resid: %d, index: %d\n", 1309 m->offset, foff, resid, i); 1310 printf(" iosize: %ld, lblkno: %ld, flags: 0x%x, npages: %d\n", 1311 bp->b_vp->v_mount->mnt_stat.f_iosize, 1312 bp->b_lblkno, bp->b_flags, bp->b_npages); 1313 printf(" valid: 0x%x, dirty: 0x%x, mapped: %d\n", 1314 m->valid, m->dirty, m->bmapped); 1315 panic("biodone: page busy < 0\n"); 1316 } 1317 --m->busy; 1318 if ((m->busy == 0) && (m->flags & PG_WANTED)) { 1319 m->flags &= ~PG_WANTED; 1320 wakeup(m); 1321 } 1322 --obj->paging_in_progress; 1323 foff += resid; 1324 iosize -= resid; 1325 } 1326 if (obj && obj->paging_in_progress == 0 && 1327 (obj->flags & OBJ_PIPWNT)) { 1328 obj->flags &= ~OBJ_PIPWNT; 1329 wakeup(obj); 1330 } 1331 } 1332 /* 1333 * For asynchronous completions, release the buffer now. The brelse 1334 * checks for B_WANTED and will do the wakeup there if necessary - so 1335 * no need to do a wakeup here in the async case. 1336 */ 1337 1338 if (bp->b_flags & B_ASYNC) { 1339 brelse(bp); 1340 } else { 1341 bp->b_flags &= ~B_WANTED; 1342 wakeup(bp); 1343 } 1344 splx(s); 1345 } 1346 1347 int 1348 count_lock_queue() 1349 { 1350 int count; 1351 struct buf *bp; 1352 1353 count = 0; 1354 for (bp = bufqueues[QUEUE_LOCKED].tqh_first; 1355 bp != NULL; 1356 bp = bp->b_freelist.tqe_next) 1357 count++; 1358 return (count); 1359 } 1360 1361 int vfs_update_interval = 30; 1362 1363 void 1364 vfs_update() 1365 { 1366 (void) spl0(); 1367 while (1) { 1368 tsleep(&vfs_update_wakeup, PRIBIO, "update", 1369 hz * vfs_update_interval); 1370 vfs_update_wakeup = 0; 1371 sync(curproc, NULL, NULL); 1372 } 1373 } 1374 1375 /* 1376 * This routine is called in lieu of iodone in the case of 1377 * incomplete I/O. This keeps the busy status for pages 1378 * consistant. 1379 */ 1380 void 1381 vfs_unbusy_pages(struct buf * bp) 1382 { 1383 int i; 1384 1385 if (bp->b_flags & B_VMIO) { 1386 struct vnode *vp = bp->b_vp; 1387 vm_object_t obj = vp->v_object; 1388 vm_offset_t foff; 1389 1390 foff = trunc_page(vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno); 1391 1392 for (i = 0; i < bp->b_npages; i++) { 1393 vm_page_t m = bp->b_pages[i]; 1394 1395 if (m == bogus_page) { 1396 m = vm_page_lookup(obj, foff + i * PAGE_SIZE); 1397 if (!m) { 1398 panic("vfs_unbusy_pages: page missing\n"); 1399 } 1400 bp->b_pages[i] = m; 1401 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 1402 } 1403 --obj->paging_in_progress; 1404 --m->busy; 1405 if ((m->busy == 0) && (m->flags & PG_WANTED)) { 1406 m->flags &= ~PG_WANTED; 1407 wakeup(m); 1408 } 1409 } 1410 if (obj->paging_in_progress == 0 && 1411 (obj->flags & OBJ_PIPWNT)) { 1412 obj->flags &= ~OBJ_PIPWNT; 1413 wakeup(obj); 1414 } 1415 } 1416 } 1417 1418 /* 1419 * This routine is called before a device strategy routine. 1420 * It is used to tell the VM system that paging I/O is in 1421 * progress, and treat the pages associated with the buffer 1422 * almost as being PG_BUSY. Also the object paging_in_progress 1423 * flag is handled to make sure that the object doesn't become 1424 * inconsistant. 1425 */ 1426 void 1427 vfs_busy_pages(struct buf * bp, int clear_modify) 1428 { 1429 int i; 1430 1431 if (bp->b_flags & B_VMIO) { 1432 vm_object_t obj = bp->b_vp->v_object; 1433 vm_offset_t foff = bp->b_vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 1434 int iocount = bp->b_bufsize; 1435 1436 vfs_setdirty(bp); 1437 for (i = 0; i < bp->b_npages; i++) { 1438 vm_page_t m = bp->b_pages[i]; 1439 int resid = (m->offset + PAGE_SIZE) - foff; 1440 1441 if (resid > iocount) 1442 resid = iocount; 1443 if ((bp->b_flags & B_CLUSTER) == 0) { 1444 obj->paging_in_progress++; 1445 m->busy++; 1446 } 1447 if (clear_modify) { 1448 vm_page_protect(m, VM_PROT_READ); 1449 vm_page_set_validclean(m, 1450 foff & (PAGE_SIZE-1), resid); 1451 } else if (bp->b_bcount >= PAGE_SIZE) { 1452 if (m->valid && (bp->b_flags & B_CACHE) == 0) { 1453 bp->b_pages[i] = bogus_page; 1454 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 1455 } 1456 } 1457 foff += resid; 1458 iocount -= resid; 1459 } 1460 } 1461 } 1462 1463 /* 1464 * Tell the VM system that the pages associated with this buffer 1465 * are clean. This is used for delayed writes where the data is 1466 * going to go to disk eventually without additional VM intevention. 1467 */ 1468 void 1469 vfs_clean_pages(struct buf * bp) 1470 { 1471 int i; 1472 1473 if (bp->b_flags & B_VMIO) { 1474 vm_offset_t foff = 1475 bp->b_vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 1476 int iocount = bp->b_bufsize; 1477 1478 for (i = 0; i < bp->b_npages; i++) { 1479 vm_page_t m = bp->b_pages[i]; 1480 int resid = (m->offset + PAGE_SIZE) - foff; 1481 1482 if (resid > iocount) 1483 resid = iocount; 1484 if (resid > 0) { 1485 vm_page_set_validclean(m, 1486 foff & (PAGE_SIZE-1), resid); 1487 } 1488 foff += resid; 1489 iocount -= resid; 1490 } 1491 } 1492 } 1493 1494 void 1495 vfs_bio_clrbuf(struct buf *bp) { 1496 int i; 1497 if( bp->b_flags & B_VMIO) { 1498 if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE)) { 1499 int j; 1500 if( bp->b_pages[0]->valid != VM_PAGE_BITS_ALL) { 1501 for(j=0; j < bp->b_bufsize / DEV_BSIZE;j++) { 1502 bzero(bp->b_data + j * DEV_BSIZE, DEV_BSIZE); 1503 } 1504 } 1505 bp->b_resid = 0; 1506 return; 1507 } 1508 for(i=0;i<bp->b_npages;i++) { 1509 if( bp->b_pages[i]->valid == VM_PAGE_BITS_ALL) 1510 continue; 1511 if( bp->b_pages[i]->valid == 0) { 1512 bzero(bp->b_data + i * PAGE_SIZE, PAGE_SIZE); 1513 } else { 1514 int j; 1515 for(j=0;j<PAGE_SIZE/DEV_BSIZE;j++) { 1516 if( (bp->b_pages[i]->valid & (1<<j)) == 0) 1517 bzero(bp->b_data + i * PAGE_SIZE + j * DEV_BSIZE, DEV_BSIZE); 1518 } 1519 } 1520 bp->b_pages[i]->valid = VM_PAGE_BITS_ALL; 1521 } 1522 bp->b_resid = 0; 1523 } else { 1524 clrbuf(bp); 1525 } 1526 } 1527 1528 /* 1529 * vm_hold_load_pages and vm_hold_unload pages get pages into 1530 * a buffers address space. The pages are anonymous and are 1531 * not associated with a file object. 1532 */ 1533 void 1534 vm_hold_load_pages(struct buf * bp, vm_offset_t froma, vm_offset_t toa) 1535 { 1536 vm_offset_t pg; 1537 vm_page_t p; 1538 vm_offset_t from = round_page(froma); 1539 vm_offset_t to = round_page(toa); 1540 1541 for (pg = from; pg < to; pg += PAGE_SIZE) { 1542 1543 tryagain: 1544 1545 p = vm_page_alloc(kernel_object, pg - VM_MIN_KERNEL_ADDRESS, 1546 VM_ALLOC_NORMAL); 1547 if (!p) { 1548 VM_WAIT; 1549 goto tryagain; 1550 } 1551 vm_page_wire(p); 1552 pmap_kenter(pg, VM_PAGE_TO_PHYS(p)); 1553 bp->b_pages[((caddr_t) pg - bp->b_data) / PAGE_SIZE] = p; 1554 PAGE_WAKEUP(p); 1555 bp->b_npages++; 1556 } 1557 } 1558 1559 void 1560 vm_hold_free_pages(struct buf * bp, vm_offset_t froma, vm_offset_t toa) 1561 { 1562 vm_offset_t pg; 1563 vm_page_t p; 1564 vm_offset_t from = round_page(froma); 1565 vm_offset_t to = round_page(toa); 1566 1567 for (pg = from; pg < to; pg += PAGE_SIZE) { 1568 p = bp->b_pages[((caddr_t) pg - bp->b_data) / PAGE_SIZE]; 1569 bp->b_pages[((caddr_t) pg - bp->b_data) / PAGE_SIZE] = 0; 1570 pmap_kremove(pg); 1571 vm_page_free(p); 1572 --bp->b_npages; 1573 } 1574 } 1575