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 1.120 1997/06/13 08:30:40 bde 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 #include "opt_bounce.h" 36 37 #define VMIO 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/sysproto.h> 41 #include <sys/kernel.h> 42 #include <sys/sysctl.h> 43 #include <sys/proc.h> 44 #include <sys/vnode.h> 45 #include <sys/vmmeter.h> 46 #include <vm/vm.h> 47 #include <vm/vm_param.h> 48 #include <vm/vm_prot.h> 49 #include <vm/vm_kern.h> 50 #include <vm/vm_pageout.h> 51 #include <vm/vm_page.h> 52 #include <vm/vm_object.h> 53 #include <vm/vm_extern.h> 54 #include <vm/vm_map.h> 55 #include <sys/buf.h> 56 #include <sys/mount.h> 57 #include <sys/malloc.h> 58 #include <sys/resourcevar.h> 59 #include <sys/proc.h> 60 61 #include <miscfs/specfs/specdev.h> 62 63 static void vfs_update __P((void)); 64 static struct proc *updateproc; 65 static struct kproc_desc up_kp = { 66 "update", 67 vfs_update, 68 &updateproc 69 }; 70 SYSINIT_KT(update, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp) 71 72 struct buf *buf; /* buffer header pool */ 73 struct swqueue bswlist; 74 75 int count_lock_queue __P((void)); 76 static void vm_hold_free_pages(struct buf * bp, vm_offset_t from, 77 vm_offset_t to); 78 static void vm_hold_load_pages(struct buf * bp, vm_offset_t from, 79 vm_offset_t to); 80 static void vfs_buf_set_valid(struct buf *bp, vm_ooffset_t foff, 81 vm_offset_t off, vm_offset_t size, 82 vm_page_t m); 83 static void vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, 84 int pageno, vm_page_t m); 85 static void vfs_clean_pages(struct buf * bp); 86 static void vfs_setdirty(struct buf *bp); 87 static void vfs_vmio_release(struct buf *bp); 88 static void flushdirtybuffers(int slpflag, int slptimeo); 89 90 int needsbuffer; 91 92 /* 93 * Internal update daemon, process 3 94 * The variable vfs_update_wakeup allows for internal syncs. 95 */ 96 int vfs_update_wakeup; 97 98 99 /* 100 * buffers base kva 101 */ 102 103 /* 104 * bogus page -- for I/O to/from partially complete buffers 105 * this is a temporary solution to the problem, but it is not 106 * really that bad. it would be better to split the buffer 107 * for input in the case of buffers partially already in memory, 108 * but the code is intricate enough already. 109 */ 110 vm_page_t bogus_page; 111 static vm_offset_t bogus_offset; 112 113 static int bufspace, maxbufspace, vmiospace, maxvmiobufspace, 114 bufmallocspace, maxbufmallocspace; 115 int numdirtybuffers, lodirtybuffers, hidirtybuffers; 116 static int numfreebuffers, lofreebuffers, hifreebuffers; 117 118 SYSCTL_INT(_vfs, OID_AUTO, numdirtybuffers, CTLFLAG_RD, 119 &numdirtybuffers, 0, ""); 120 SYSCTL_INT(_vfs, OID_AUTO, lodirtybuffers, CTLFLAG_RW, 121 &lodirtybuffers, 0, ""); 122 SYSCTL_INT(_vfs, OID_AUTO, hidirtybuffers, CTLFLAG_RW, 123 &hidirtybuffers, 0, ""); 124 SYSCTL_INT(_vfs, OID_AUTO, numfreebuffers, CTLFLAG_RD, 125 &numfreebuffers, 0, ""); 126 SYSCTL_INT(_vfs, OID_AUTO, lofreebuffers, CTLFLAG_RW, 127 &lofreebuffers, 0, ""); 128 SYSCTL_INT(_vfs, OID_AUTO, hifreebuffers, CTLFLAG_RW, 129 &hifreebuffers, 0, ""); 130 SYSCTL_INT(_vfs, OID_AUTO, maxbufspace, CTLFLAG_RW, 131 &maxbufspace, 0, ""); 132 SYSCTL_INT(_vfs, OID_AUTO, bufspace, CTLFLAG_RD, 133 &bufspace, 0, ""); 134 SYSCTL_INT(_vfs, OID_AUTO, maxvmiobufspace, CTLFLAG_RW, 135 &maxvmiobufspace, 0, ""); 136 SYSCTL_INT(_vfs, OID_AUTO, vmiospace, CTLFLAG_RD, 137 &vmiospace, 0, ""); 138 SYSCTL_INT(_vfs, OID_AUTO, maxmallocbufspace, CTLFLAG_RW, 139 &maxbufmallocspace, 0, ""); 140 SYSCTL_INT(_vfs, OID_AUTO, bufmallocspace, CTLFLAG_RD, 141 &bufmallocspace, 0, ""); 142 143 static struct bufhashhdr bufhashtbl[BUFHSZ], invalhash; 144 static struct bqueues bufqueues[BUFFER_QUEUES]; 145 146 extern int vm_swap_size; 147 148 #define BUF_MAXUSE 24 149 150 #define VFS_BIO_NEED_ANY 1 151 #define VFS_BIO_NEED_LOWLIMIT 2 152 #define VFS_BIO_NEED_FREE 4 153 154 /* 155 * Initialize buffer headers and related structures. 156 */ 157 void 158 bufinit() 159 { 160 struct buf *bp; 161 int i; 162 163 TAILQ_INIT(&bswlist); 164 LIST_INIT(&invalhash); 165 166 /* first, make a null hash table */ 167 for (i = 0; i < BUFHSZ; i++) 168 LIST_INIT(&bufhashtbl[i]); 169 170 /* next, make a null set of free lists */ 171 for (i = 0; i < BUFFER_QUEUES; i++) 172 TAILQ_INIT(&bufqueues[i]); 173 174 /* finally, initialize each buffer header and stick on empty q */ 175 for (i = 0; i < nbuf; i++) { 176 bp = &buf[i]; 177 bzero(bp, sizeof *bp); 178 bp->b_flags = B_INVAL; /* we're just an empty header */ 179 bp->b_dev = NODEV; 180 bp->b_rcred = NOCRED; 181 bp->b_wcred = NOCRED; 182 bp->b_qindex = QUEUE_EMPTY; 183 bp->b_vnbufs.le_next = NOLIST; 184 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 185 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 186 } 187 /* 188 * maxbufspace is currently calculated to support all filesystem blocks 189 * to be 8K. If you happen to use a 16K filesystem, the size of the buffer 190 * cache is still the same as it would be for 8K filesystems. This 191 * keeps the size of the buffer cache "in check" for big block filesystems. 192 */ 193 maxbufspace = (nbuf + 8) * DFLTBSIZE; 194 /* 195 * reserve 1/3 of the buffers for metadata (VDIR) which might not be VMIO'ed 196 */ 197 maxvmiobufspace = 2 * maxbufspace / 3; 198 /* 199 * Limit the amount of malloc memory since it is wired permanently into 200 * the kernel space. Even though this is accounted for in the buffer 201 * allocation, we don't want the malloced region to grow uncontrolled. 202 * The malloc scheme improves memory utilization significantly on average 203 * (small) directories. 204 */ 205 maxbufmallocspace = maxbufspace / 20; 206 207 /* 208 * Remove the probability of deadlock conditions by limiting the 209 * number of dirty buffers. 210 */ 211 hidirtybuffers = nbuf / 6 + 20; 212 lodirtybuffers = nbuf / 12 + 10; 213 numdirtybuffers = 0; 214 lofreebuffers = nbuf / 18 + 5; 215 hifreebuffers = 2 * lofreebuffers; 216 numfreebuffers = nbuf; 217 218 bogus_offset = kmem_alloc_pageable(kernel_map, PAGE_SIZE); 219 bogus_page = vm_page_alloc(kernel_object, 220 ((bogus_offset - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), 221 VM_ALLOC_NORMAL); 222 223 } 224 225 /* 226 * Free the kva allocation for a buffer 227 * Must be called only at splbio or higher, 228 * as this is the only locking for buffer_map. 229 */ 230 static void 231 bfreekva(struct buf * bp) 232 { 233 if (bp->b_kvasize == 0) 234 return; 235 236 vm_map_delete(buffer_map, 237 (vm_offset_t) bp->b_kvabase, 238 (vm_offset_t) bp->b_kvabase + bp->b_kvasize); 239 240 bp->b_kvasize = 0; 241 242 } 243 244 /* 245 * remove the buffer from the appropriate free list 246 */ 247 void 248 bremfree(struct buf * bp) 249 { 250 int s = splbio(); 251 252 if (bp->b_qindex != QUEUE_NONE) { 253 TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist); 254 bp->b_qindex = QUEUE_NONE; 255 } else { 256 #if !defined(MAX_PERF) 257 panic("bremfree: removing a buffer when not on a queue"); 258 #endif 259 } 260 if ((bp->b_flags & B_INVAL) || 261 (bp->b_flags & (B_DELWRI|B_LOCKED)) == 0) 262 --numfreebuffers; 263 splx(s); 264 } 265 266 /* 267 * Get a buffer with the specified data. Look in the cache first. 268 */ 269 int 270 bread(struct vnode * vp, daddr_t blkno, int size, struct ucred * cred, 271 struct buf ** bpp) 272 { 273 struct buf *bp; 274 275 bp = getblk(vp, blkno, size, 0, 0); 276 *bpp = bp; 277 278 /* if not found in cache, do some I/O */ 279 if ((bp->b_flags & B_CACHE) == 0) { 280 if (curproc != NULL) 281 curproc->p_stats->p_ru.ru_inblock++; 282 bp->b_flags |= B_READ; 283 bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 284 if (bp->b_rcred == NOCRED) { 285 if (cred != NOCRED) 286 crhold(cred); 287 bp->b_rcred = cred; 288 } 289 vfs_busy_pages(bp, 0); 290 VOP_STRATEGY(bp); 291 return (biowait(bp)); 292 } 293 return (0); 294 } 295 296 /* 297 * Operates like bread, but also starts asynchronous I/O on 298 * read-ahead blocks. 299 */ 300 int 301 breadn(struct vnode * vp, daddr_t blkno, int size, 302 daddr_t * rablkno, int *rabsize, 303 int cnt, struct ucred * cred, struct buf ** bpp) 304 { 305 struct buf *bp, *rabp; 306 int i; 307 int rv = 0, readwait = 0; 308 309 *bpp = bp = getblk(vp, blkno, size, 0, 0); 310 311 /* if not found in cache, do some I/O */ 312 if ((bp->b_flags & B_CACHE) == 0) { 313 if (curproc != NULL) 314 curproc->p_stats->p_ru.ru_inblock++; 315 bp->b_flags |= B_READ; 316 bp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 317 if (bp->b_rcred == NOCRED) { 318 if (cred != NOCRED) 319 crhold(cred); 320 bp->b_rcred = cred; 321 } 322 vfs_busy_pages(bp, 0); 323 VOP_STRATEGY(bp); 324 ++readwait; 325 } 326 for (i = 0; i < cnt; i++, rablkno++, rabsize++) { 327 if (inmem(vp, *rablkno)) 328 continue; 329 rabp = getblk(vp, *rablkno, *rabsize, 0, 0); 330 331 if ((rabp->b_flags & B_CACHE) == 0) { 332 if (curproc != NULL) 333 curproc->p_stats->p_ru.ru_inblock++; 334 rabp->b_flags |= B_READ | B_ASYNC; 335 rabp->b_flags &= ~(B_DONE | B_ERROR | B_INVAL); 336 if (rabp->b_rcred == NOCRED) { 337 if (cred != NOCRED) 338 crhold(cred); 339 rabp->b_rcred = cred; 340 } 341 vfs_busy_pages(rabp, 0); 342 VOP_STRATEGY(rabp); 343 } else { 344 brelse(rabp); 345 } 346 } 347 348 if (readwait) { 349 rv = biowait(bp); 350 } 351 return (rv); 352 } 353 354 /* 355 * Write, release buffer on completion. (Done by iodone 356 * if async.) 357 */ 358 int 359 bwrite(struct buf * bp) 360 { 361 int oldflags = bp->b_flags; 362 363 if (bp->b_flags & B_INVAL) { 364 brelse(bp); 365 return (0); 366 } 367 #if !defined(MAX_PERF) 368 if (!(bp->b_flags & B_BUSY)) 369 panic("bwrite: buffer is not busy???"); 370 #endif 371 372 bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI); 373 bp->b_flags |= B_WRITEINPROG; 374 375 if ((oldflags & B_DELWRI) == B_DELWRI) { 376 --numdirtybuffers; 377 reassignbuf(bp, bp->b_vp); 378 } 379 380 bp->b_vp->v_numoutput++; 381 vfs_busy_pages(bp, 1); 382 if (curproc != NULL) 383 curproc->p_stats->p_ru.ru_oublock++; 384 VOP_STRATEGY(bp); 385 386 /* 387 * Handle ordered writes here. 388 * If the write was originally flagged as ordered, 389 * then we check to see if it was converted to async. 390 * If it was converted to async, and is done now, then 391 * we release the buffer. Otherwise we clear the 392 * ordered flag because it is not needed anymore. 393 * 394 * Note that biodone has been modified so that it does 395 * not release ordered buffers. This allows us to have 396 * a chance to determine whether or not the driver 397 * has set the async flag in the strategy routine. Otherwise 398 * if biodone was not modified, then the buffer may have been 399 * reused before we have had a chance to check the flag. 400 */ 401 402 if ((oldflags & B_ORDERED) == B_ORDERED) { 403 int s; 404 s = splbio(); 405 if (bp->b_flags & B_ASYNC) { 406 if ((bp->b_flags & B_DONE)) { 407 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0) 408 brelse(bp); 409 else 410 bqrelse(bp); 411 } 412 splx(s); 413 return (0); 414 } else { 415 bp->b_flags &= ~B_ORDERED; 416 } 417 splx(s); 418 } 419 420 if ((oldflags & B_ASYNC) == 0) { 421 int rtval = biowait(bp); 422 423 if (oldflags & B_DELWRI) { 424 reassignbuf(bp, bp->b_vp); 425 } 426 brelse(bp); 427 return (rtval); 428 } 429 return (0); 430 } 431 432 int 433 vn_bwrite(ap) 434 struct vop_bwrite_args *ap; 435 { 436 return (bwrite(ap->a_bp)); 437 } 438 439 void 440 vfs_bio_need_satisfy(void) { 441 ++numfreebuffers; 442 if (!needsbuffer) 443 return; 444 if (numdirtybuffers < lodirtybuffers) { 445 needsbuffer &= ~(VFS_BIO_NEED_ANY | VFS_BIO_NEED_LOWLIMIT); 446 } else { 447 needsbuffer &= ~VFS_BIO_NEED_ANY; 448 } 449 if (numfreebuffers >= hifreebuffers) { 450 needsbuffer &= ~VFS_BIO_NEED_FREE; 451 } 452 wakeup(&needsbuffer); 453 } 454 455 /* 456 * Delayed write. (Buffer is marked dirty). 457 */ 458 void 459 bdwrite(struct buf * bp) 460 { 461 462 #if !defined(MAX_PERF) 463 if ((bp->b_flags & B_BUSY) == 0) { 464 panic("bdwrite: buffer is not busy"); 465 } 466 #endif 467 468 if (bp->b_flags & B_INVAL) { 469 brelse(bp); 470 return; 471 } 472 if (bp->b_flags & B_TAPE) { 473 bawrite(bp); 474 return; 475 } 476 bp->b_flags &= ~(B_READ|B_RELBUF); 477 if ((bp->b_flags & B_DELWRI) == 0) { 478 bp->b_flags |= B_DONE | B_DELWRI; 479 reassignbuf(bp, bp->b_vp); 480 ++numdirtybuffers; 481 } 482 483 /* 484 * This bmap keeps the system from needing to do the bmap later, 485 * perhaps when the system is attempting to do a sync. Since it 486 * is likely that the indirect block -- or whatever other datastructure 487 * that the filesystem needs is still in memory now, it is a good 488 * thing to do this. Note also, that if the pageout daemon is 489 * requesting a sync -- there might not be enough memory to do 490 * the bmap then... So, this is important to do. 491 */ 492 if( bp->b_lblkno == bp->b_blkno) { 493 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 494 } 495 496 /* 497 * Set the *dirty* buffer range based upon the VM system dirty pages. 498 */ 499 vfs_setdirty(bp); 500 501 /* 502 * We need to do this here to satisfy the vnode_pager and the 503 * pageout daemon, so that it thinks that the pages have been 504 * "cleaned". Note that since the pages are in a delayed write 505 * buffer -- the VFS layer "will" see that the pages get written 506 * out on the next sync, or perhaps the cluster will be completed. 507 */ 508 vfs_clean_pages(bp); 509 bqrelse(bp); 510 511 if (numdirtybuffers >= hidirtybuffers) 512 flushdirtybuffers(0, 0); 513 514 return; 515 } 516 517 /* 518 * Asynchronous write. 519 * Start output on a buffer, but do not wait for it to complete. 520 * The buffer is released when the output completes. 521 */ 522 void 523 bawrite(struct buf * bp) 524 { 525 bp->b_flags |= B_ASYNC; 526 (void) VOP_BWRITE(bp); 527 } 528 529 /* 530 * Ordered write. 531 * Start output on a buffer, but only wait for it to complete if the 532 * output device cannot guarantee ordering in some other way. Devices 533 * that can perform asynchronous ordered writes will set the B_ASYNC 534 * flag in their strategy routine. 535 * The buffer is released when the output completes. 536 */ 537 int 538 bowrite(struct buf * bp) 539 { 540 bp->b_flags |= B_ORDERED; 541 return (VOP_BWRITE(bp)); 542 } 543 544 /* 545 * Release a buffer. 546 */ 547 void 548 brelse(struct buf * bp) 549 { 550 int s; 551 552 if (bp->b_flags & B_CLUSTER) { 553 relpbuf(bp); 554 return; 555 } 556 /* anyone need a "free" block? */ 557 s = splbio(); 558 559 /* anyone need this block? */ 560 if (bp->b_flags & B_WANTED) { 561 bp->b_flags &= ~(B_WANTED | B_AGE); 562 wakeup(bp); 563 } 564 565 if (bp->b_flags & B_LOCKED) 566 bp->b_flags &= ~B_ERROR; 567 568 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR)) || 569 (bp->b_bufsize <= 0)) { 570 bp->b_flags |= B_INVAL; 571 if (bp->b_flags & B_DELWRI) 572 --numdirtybuffers; 573 bp->b_flags &= ~(B_DELWRI | B_CACHE); 574 if (((bp->b_flags & B_VMIO) == 0) && bp->b_vp) { 575 if (bp->b_bufsize) 576 allocbuf(bp, 0); 577 brelvp(bp); 578 } 579 } 580 581 /* 582 * VMIO buffer rundown. It is not very necessary to keep a VMIO buffer 583 * constituted, so the B_INVAL flag is used to *invalidate* the buffer, 584 * but the VM object is kept around. The B_NOCACHE flag is used to 585 * invalidate the pages in the VM object. 586 * 587 * If the buffer is a partially filled NFS buffer, keep it 588 * since invalidating it now will lose informatio. The valid 589 * flags in the vm_pages have only DEV_BSIZE resolution but 590 * the b_validoff, b_validend fields have byte resolution. 591 * This can avoid unnecessary re-reads of the buffer. 592 * XXX this seems to cause performance problems. 593 */ 594 if ((bp->b_flags & B_VMIO) 595 && !(bp->b_vp->v_tag == VT_NFS && 596 (bp->b_flags & B_DELWRI) != 0) 597 #ifdef notdef 598 && (bp->b_vp->v_tag != VT_NFS 599 || (bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR)) 600 || bp->b_validend == 0 601 || (bp->b_validoff == 0 602 && bp->b_validend == bp->b_bufsize)) 603 #endif 604 ) { 605 vm_ooffset_t foff; 606 vm_object_t obj; 607 int i, resid; 608 vm_page_t m; 609 struct vnode *vp; 610 int iototal = bp->b_bufsize; 611 612 vp = bp->b_vp; 613 614 #if !defined(MAX_PERF) 615 if (!vp) 616 panic("brelse: missing vp"); 617 #endif 618 619 if (bp->b_npages) { 620 vm_pindex_t poff; 621 obj = (vm_object_t) vp->v_object; 622 if (vp->v_type == VBLK) 623 foff = ((vm_ooffset_t) bp->b_lblkno) << DEV_BSHIFT; 624 else 625 foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 626 poff = OFF_TO_IDX(foff); 627 for (i = 0; i < bp->b_npages; i++) { 628 m = bp->b_pages[i]; 629 if (m == bogus_page) { 630 m = vm_page_lookup(obj, poff + i); 631 #if !defined(MAX_PERF) 632 if (!m) { 633 panic("brelse: page missing\n"); 634 } 635 #endif 636 bp->b_pages[i] = m; 637 pmap_qenter(trunc_page(bp->b_data), 638 bp->b_pages, bp->b_npages); 639 } 640 resid = IDX_TO_OFF(m->pindex+1) - foff; 641 if (resid > iototal) 642 resid = iototal; 643 if (resid > 0) { 644 /* 645 * Don't invalidate the page if the local machine has already 646 * modified it. This is the lesser of two evils, and should 647 * be fixed. 648 */ 649 if (bp->b_flags & (B_NOCACHE | B_ERROR)) { 650 vm_page_test_dirty(m); 651 if (m->dirty == 0) { 652 vm_page_set_invalid(m, (vm_offset_t) foff, resid); 653 if (m->valid == 0) 654 vm_page_protect(m, VM_PROT_NONE); 655 } 656 } 657 if (resid >= PAGE_SIZE) { 658 if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { 659 bp->b_flags |= B_INVAL; 660 } 661 } else { 662 if (!vm_page_is_valid(m, 663 (((vm_offset_t) bp->b_data) & PAGE_MASK), resid)) { 664 bp->b_flags |= B_INVAL; 665 } 666 } 667 } 668 foff += resid; 669 iototal -= resid; 670 } 671 } 672 if (bp->b_flags & (B_INVAL | B_RELBUF)) 673 vfs_vmio_release(bp); 674 } 675 #if !defined(MAX_PERF) 676 if (bp->b_qindex != QUEUE_NONE) 677 panic("brelse: free buffer onto another queue???"); 678 #endif 679 680 /* enqueue */ 681 /* buffers with no memory */ 682 if (bp->b_bufsize == 0) { 683 bp->b_flags |= B_INVAL; 684 bp->b_qindex = QUEUE_EMPTY; 685 TAILQ_INSERT_HEAD(&bufqueues[QUEUE_EMPTY], bp, b_freelist); 686 LIST_REMOVE(bp, b_hash); 687 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 688 bp->b_dev = NODEV; 689 /* 690 * Get rid of the kva allocation *now* 691 */ 692 bfreekva(bp); 693 694 /* buffers with junk contents */ 695 } else if (bp->b_flags & (B_ERROR | B_INVAL | B_NOCACHE | B_RELBUF)) { 696 bp->b_flags |= B_INVAL; 697 bp->b_qindex = QUEUE_AGE; 698 TAILQ_INSERT_HEAD(&bufqueues[QUEUE_AGE], bp, b_freelist); 699 LIST_REMOVE(bp, b_hash); 700 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 701 bp->b_dev = NODEV; 702 703 /* buffers that are locked */ 704 } else if (bp->b_flags & B_LOCKED) { 705 bp->b_qindex = QUEUE_LOCKED; 706 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); 707 708 /* buffers with stale but valid contents */ 709 } else if (bp->b_flags & B_AGE) { 710 bp->b_qindex = QUEUE_AGE; 711 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_AGE], bp, b_freelist); 712 713 /* buffers with valid and quite potentially reuseable contents */ 714 } else { 715 bp->b_qindex = QUEUE_LRU; 716 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 717 } 718 719 if ((bp->b_flags & B_INVAL) || 720 (bp->b_flags & (B_LOCKED|B_DELWRI)) == 0) { 721 if (bp->b_flags & B_DELWRI) { 722 --numdirtybuffers; 723 bp->b_flags &= ~B_DELWRI; 724 } 725 vfs_bio_need_satisfy(); 726 } 727 728 /* unlock */ 729 bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY | 730 B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 731 splx(s); 732 } 733 734 /* 735 * Release a buffer. 736 */ 737 void 738 bqrelse(struct buf * bp) 739 { 740 int s; 741 742 s = splbio(); 743 744 /* anyone need this block? */ 745 if (bp->b_flags & B_WANTED) { 746 bp->b_flags &= ~(B_WANTED | B_AGE); 747 wakeup(bp); 748 } 749 750 #if !defined(MAX_PERF) 751 if (bp->b_qindex != QUEUE_NONE) 752 panic("bqrelse: free buffer onto another queue???"); 753 #endif 754 755 if (bp->b_flags & B_LOCKED) { 756 bp->b_flags &= ~B_ERROR; 757 bp->b_qindex = QUEUE_LOCKED; 758 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist); 759 /* buffers with stale but valid contents */ 760 } else { 761 bp->b_qindex = QUEUE_LRU; 762 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 763 } 764 765 if ((bp->b_flags & (B_LOCKED|B_DELWRI)) == 0) { 766 vfs_bio_need_satisfy(); 767 } 768 769 /* unlock */ 770 bp->b_flags &= ~(B_ORDERED | B_WANTED | B_BUSY | 771 B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF); 772 splx(s); 773 } 774 775 static void 776 vfs_vmio_release(bp) 777 struct buf *bp; 778 { 779 int i; 780 vm_page_t m; 781 782 for (i = 0; i < bp->b_npages; i++) { 783 m = bp->b_pages[i]; 784 bp->b_pages[i] = NULL; 785 vm_page_unwire(m); 786 /* 787 * We don't mess with busy pages, it is 788 * the responsibility of the process that 789 * busied the pages to deal with them. 790 */ 791 if ((m->flags & PG_BUSY) || (m->busy != 0)) 792 continue; 793 794 if (m->wire_count == 0) { 795 796 if (m->flags & PG_WANTED) { 797 m->flags &= ~PG_WANTED; 798 wakeup(m); 799 } 800 801 /* 802 * If this is an async free -- we cannot place 803 * pages onto the cache queue. If it is an 804 * async free, then we don't modify any queues. 805 * This is probably in error (for perf reasons), 806 * and we will eventually need to build 807 * a more complete infrastructure to support I/O 808 * rundown. 809 */ 810 if ((bp->b_flags & B_ASYNC) == 0) { 811 812 /* 813 * In the case of sync buffer frees, we can do pretty much 814 * anything to any of the memory queues. Specifically, 815 * the cache queue is okay to be modified. 816 */ 817 if (m->valid) { 818 if(m->dirty == 0) 819 vm_page_test_dirty(m); 820 /* 821 * this keeps pressure off of the process memory 822 */ 823 if (m->dirty == 0 && m->hold_count == 0) 824 vm_page_cache(m); 825 else 826 vm_page_deactivate(m); 827 } else if (m->hold_count == 0) { 828 vm_page_protect(m, VM_PROT_NONE); 829 vm_page_free(m); 830 } 831 } else { 832 /* 833 * If async, then at least we clear the 834 * act_count. 835 */ 836 m->act_count = 0; 837 } 838 } 839 } 840 bufspace -= bp->b_bufsize; 841 vmiospace -= bp->b_bufsize; 842 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 843 bp->b_npages = 0; 844 bp->b_bufsize = 0; 845 bp->b_flags &= ~B_VMIO; 846 if (bp->b_vp) 847 brelvp(bp); 848 } 849 850 /* 851 * Check to see if a block is currently memory resident. 852 */ 853 struct buf * 854 gbincore(struct vnode * vp, daddr_t blkno) 855 { 856 struct buf *bp; 857 struct bufhashhdr *bh; 858 859 bh = BUFHASH(vp, blkno); 860 bp = bh->lh_first; 861 862 /* Search hash chain */ 863 while (bp != NULL) { 864 /* hit */ 865 if (bp->b_vp == vp && bp->b_lblkno == blkno && 866 (bp->b_flags & B_INVAL) == 0) { 867 break; 868 } 869 bp = bp->b_hash.le_next; 870 } 871 return (bp); 872 } 873 874 /* 875 * this routine implements clustered async writes for 876 * clearing out B_DELWRI buffers... This is much better 877 * than the old way of writing only one buffer at a time. 878 */ 879 int 880 vfs_bio_awrite(struct buf * bp) 881 { 882 int i; 883 daddr_t lblkno = bp->b_lblkno; 884 struct vnode *vp = bp->b_vp; 885 int s; 886 int ncl; 887 struct buf *bpa; 888 int nwritten; 889 890 s = splbio(); 891 /* 892 * right now we support clustered writing only to regular files 893 */ 894 if ((vp->v_type == VREG) && 895 (vp->v_mount != 0) && /* Only on nodes that have the size info */ 896 (bp->b_flags & (B_CLUSTEROK | B_INVAL)) == B_CLUSTEROK) { 897 int size; 898 int maxcl; 899 900 size = vp->v_mount->mnt_stat.f_iosize; 901 maxcl = MAXPHYS / size; 902 903 for (i = 1; i < maxcl; i++) { 904 if ((bpa = gbincore(vp, lblkno + i)) && 905 ((bpa->b_flags & (B_BUSY | B_DELWRI | B_CLUSTEROK | B_INVAL)) == 906 (B_DELWRI | B_CLUSTEROK)) && 907 (bpa->b_bufsize == size)) { 908 if ((bpa->b_blkno == bpa->b_lblkno) || 909 (bpa->b_blkno != bp->b_blkno + ((i * size) >> DEV_BSHIFT))) 910 break; 911 } else { 912 break; 913 } 914 } 915 ncl = i; 916 /* 917 * this is a possible cluster write 918 */ 919 if (ncl != 1) { 920 nwritten = cluster_wbuild(vp, size, lblkno, ncl); 921 splx(s); 922 return nwritten; 923 } 924 } 925 bremfree(bp); 926 splx(s); 927 /* 928 * default (old) behavior, writing out only one block 929 */ 930 bp->b_flags |= B_BUSY | B_ASYNC; 931 nwritten = bp->b_bufsize; 932 (void) VOP_BWRITE(bp); 933 return nwritten; 934 } 935 936 937 /* 938 * Find a buffer header which is available for use. 939 */ 940 static struct buf * 941 getnewbuf(struct vnode *vp, int slpflag, int slptimeo, int size, int maxsize) 942 { 943 struct buf *bp; 944 int nbyteswritten = 0; 945 vm_offset_t addr; 946 static int writerecursion = 0; 947 948 start: 949 if (bufspace >= maxbufspace) 950 goto trytofreespace; 951 952 /* can we constitute a new buffer? */ 953 if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]))) { 954 #if !defined(MAX_PERF) 955 if (bp->b_qindex != QUEUE_EMPTY) 956 panic("getnewbuf: inconsistent EMPTY queue, qindex=%d", 957 bp->b_qindex); 958 #endif 959 bp->b_flags |= B_BUSY; 960 bremfree(bp); 961 goto fillbuf; 962 } 963 trytofreespace: 964 /* 965 * We keep the file I/O from hogging metadata I/O 966 * This is desirable because file data is cached in the 967 * VM/Buffer cache even if a buffer is freed. 968 */ 969 if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]))) { 970 #if !defined(MAX_PERF) 971 if (bp->b_qindex != QUEUE_AGE) 972 panic("getnewbuf: inconsistent AGE queue, qindex=%d", 973 bp->b_qindex); 974 #endif 975 } else if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]))) { 976 #if !defined(MAX_PERF) 977 if (bp->b_qindex != QUEUE_LRU) 978 panic("getnewbuf: inconsistent LRU queue, qindex=%d", 979 bp->b_qindex); 980 #endif 981 } 982 if (!bp) { 983 /* wait for a free buffer of any kind */ 984 needsbuffer |= VFS_BIO_NEED_ANY; 985 do 986 tsleep(&needsbuffer, (PRIBIO + 1) | slpflag, "newbuf", 987 slptimeo); 988 while (needsbuffer & VFS_BIO_NEED_ANY); 989 return (0); 990 } 991 992 #if defined(DIAGNOSTIC) 993 if (bp->b_flags & B_BUSY) { 994 panic("getnewbuf: busy buffer on free list\n"); 995 } 996 #endif 997 998 /* 999 * We are fairly aggressive about freeing VMIO buffers, but since 1000 * the buffering is intact without buffer headers, there is not 1001 * much loss. We gain by maintaining non-VMIOed metadata in buffers. 1002 */ 1003 if ((bp->b_qindex == QUEUE_LRU) && (bp->b_usecount > 0)) { 1004 if ((bp->b_flags & B_VMIO) == 0 || 1005 (vmiospace < maxvmiobufspace)) { 1006 --bp->b_usecount; 1007 TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist); 1008 if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) { 1009 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 1010 goto start; 1011 } 1012 TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist); 1013 } 1014 } 1015 1016 1017 /* if we are a delayed write, convert to an async write */ 1018 if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) { 1019 1020 if (writerecursion > 0) { 1021 bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); 1022 while (bp) { 1023 if ((bp->b_flags & B_DELWRI) == 0) 1024 break; 1025 bp = TAILQ_NEXT(bp, b_freelist); 1026 } 1027 if (bp == NULL) { 1028 bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]); 1029 while (bp) { 1030 if ((bp->b_flags & B_DELWRI) == 0) 1031 break; 1032 bp = TAILQ_NEXT(bp, b_freelist); 1033 } 1034 } 1035 if (bp == NULL) 1036 panic("getnewbuf: cannot get buffer, infinite recursion failure"); 1037 } else { 1038 ++writerecursion; 1039 nbyteswritten += vfs_bio_awrite(bp); 1040 --writerecursion; 1041 if (!slpflag && !slptimeo) { 1042 return (0); 1043 } 1044 goto start; 1045 } 1046 } 1047 1048 if (bp->b_flags & B_WANTED) { 1049 bp->b_flags &= ~B_WANTED; 1050 wakeup(bp); 1051 } 1052 bremfree(bp); 1053 bp->b_flags |= B_BUSY; 1054 1055 if (bp->b_flags & B_VMIO) { 1056 bp->b_flags &= ~B_ASYNC; 1057 vfs_vmio_release(bp); 1058 } 1059 1060 if (bp->b_vp) 1061 brelvp(bp); 1062 1063 fillbuf: 1064 /* we are not free, nor do we contain interesting data */ 1065 if (bp->b_rcred != NOCRED) { 1066 crfree(bp->b_rcred); 1067 bp->b_rcred = NOCRED; 1068 } 1069 if (bp->b_wcred != NOCRED) { 1070 crfree(bp->b_wcred); 1071 bp->b_wcred = NOCRED; 1072 } 1073 1074 LIST_REMOVE(bp, b_hash); 1075 LIST_INSERT_HEAD(&invalhash, bp, b_hash); 1076 if (bp->b_bufsize) { 1077 allocbuf(bp, 0); 1078 } 1079 bp->b_flags = B_BUSY; 1080 bp->b_dev = NODEV; 1081 bp->b_vp = NULL; 1082 bp->b_blkno = bp->b_lblkno = 0; 1083 bp->b_iodone = 0; 1084 bp->b_error = 0; 1085 bp->b_resid = 0; 1086 bp->b_bcount = 0; 1087 bp->b_npages = 0; 1088 bp->b_dirtyoff = bp->b_dirtyend = 0; 1089 bp->b_validoff = bp->b_validend = 0; 1090 bp->b_usecount = 4; 1091 1092 maxsize = (maxsize + PAGE_MASK) & ~PAGE_MASK; 1093 1094 /* 1095 * we assume that buffer_map is not at address 0 1096 */ 1097 addr = 0; 1098 if (maxsize != bp->b_kvasize) { 1099 bfreekva(bp); 1100 1101 /* 1102 * See if we have buffer kva space 1103 */ 1104 if (vm_map_findspace(buffer_map, 1105 vm_map_min(buffer_map), maxsize, &addr)) { 1106 bp->b_flags |= B_INVAL; 1107 brelse(bp); 1108 goto trytofreespace; 1109 } 1110 } 1111 1112 /* 1113 * See if we are below are allocated minimum 1114 */ 1115 if (bufspace >= (maxbufspace + nbyteswritten)) { 1116 bp->b_flags |= B_INVAL; 1117 brelse(bp); 1118 goto trytofreespace; 1119 } 1120 1121 /* 1122 * create a map entry for the buffer -- in essence 1123 * reserving the kva space. 1124 */ 1125 if (addr) { 1126 vm_map_insert(buffer_map, NULL, 0, 1127 addr, addr + maxsize, 1128 VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 1129 1130 bp->b_kvabase = (caddr_t) addr; 1131 bp->b_kvasize = maxsize; 1132 } 1133 bp->b_data = bp->b_kvabase; 1134 1135 return (bp); 1136 } 1137 1138 static void 1139 waitfreebuffers(int slpflag, int slptimeo) { 1140 while (numfreebuffers < hifreebuffers) { 1141 flushdirtybuffers(slpflag, slptimeo); 1142 if (numfreebuffers < hifreebuffers) 1143 break; 1144 needsbuffer |= VFS_BIO_NEED_FREE; 1145 if (tsleep(&needsbuffer, PRIBIO|slpflag, "biofre", slptimeo)) 1146 break; 1147 } 1148 } 1149 1150 static void 1151 flushdirtybuffers(int slpflag, int slptimeo) { 1152 int s; 1153 static pid_t flushing = 0; 1154 1155 s = splbio(); 1156 1157 if (flushing) { 1158 if (flushing == curproc->p_pid) { 1159 splx(s); 1160 return; 1161 } 1162 while (flushing) { 1163 if (tsleep(&flushing, PRIBIO|slpflag, "biofls", slptimeo)) { 1164 splx(s); 1165 return; 1166 } 1167 } 1168 } 1169 flushing = curproc->p_pid; 1170 1171 while (numdirtybuffers > lodirtybuffers) { 1172 struct buf *bp; 1173 needsbuffer |= VFS_BIO_NEED_LOWLIMIT; 1174 bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]); 1175 if (bp == NULL) 1176 bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]); 1177 1178 while (bp && ((bp->b_flags & B_DELWRI) == 0)) { 1179 bp = TAILQ_NEXT(bp, b_freelist); 1180 } 1181 1182 if (bp) { 1183 splx(s); 1184 vfs_bio_awrite(bp); 1185 s = splbio(); 1186 continue; 1187 } 1188 break; 1189 } 1190 1191 flushing = 0; 1192 wakeup(&flushing); 1193 splx(s); 1194 } 1195 1196 /* 1197 * Check to see if a block is currently memory resident. 1198 */ 1199 struct buf * 1200 incore(struct vnode * vp, daddr_t blkno) 1201 { 1202 struct buf *bp; 1203 1204 int s = splbio(); 1205 bp = gbincore(vp, blkno); 1206 splx(s); 1207 return (bp); 1208 } 1209 1210 /* 1211 * Returns true if no I/O is needed to access the 1212 * associated VM object. This is like incore except 1213 * it also hunts around in the VM system for the data. 1214 */ 1215 1216 int 1217 inmem(struct vnode * vp, daddr_t blkno) 1218 { 1219 vm_object_t obj; 1220 vm_offset_t toff, tinc; 1221 vm_page_t m; 1222 vm_ooffset_t off; 1223 1224 if (incore(vp, blkno)) 1225 return 1; 1226 if (vp->v_mount == NULL) 1227 return 0; 1228 if ((vp->v_object == NULL) || (vp->v_flag & VVMIO) == 0) 1229 return 0; 1230 1231 obj = vp->v_object; 1232 tinc = PAGE_SIZE; 1233 if (tinc > vp->v_mount->mnt_stat.f_iosize) 1234 tinc = vp->v_mount->mnt_stat.f_iosize; 1235 off = blkno * vp->v_mount->mnt_stat.f_iosize; 1236 1237 for (toff = 0; toff < vp->v_mount->mnt_stat.f_iosize; toff += tinc) { 1238 1239 m = vm_page_lookup(obj, OFF_TO_IDX(off + toff)); 1240 if (!m) 1241 return 0; 1242 if (vm_page_is_valid(m, (vm_offset_t) (toff + off), tinc) == 0) 1243 return 0; 1244 } 1245 return 1; 1246 } 1247 1248 /* 1249 * now we set the dirty range for the buffer -- 1250 * for NFS -- if the file is mapped and pages have 1251 * been written to, let it know. We want the 1252 * entire range of the buffer to be marked dirty if 1253 * any of the pages have been written to for consistancy 1254 * with the b_validoff, b_validend set in the nfs write 1255 * code, and used by the nfs read code. 1256 */ 1257 static void 1258 vfs_setdirty(struct buf *bp) { 1259 int i; 1260 vm_object_t object; 1261 vm_offset_t boffset, offset; 1262 /* 1263 * We qualify the scan for modified pages on whether the 1264 * object has been flushed yet. The OBJ_WRITEABLE flag 1265 * is not cleared simply by protecting pages off. 1266 */ 1267 if ((bp->b_flags & B_VMIO) && 1268 ((object = bp->b_pages[0]->object)->flags & (OBJ_WRITEABLE|OBJ_CLEANING))) { 1269 /* 1270 * test the pages to see if they have been modified directly 1271 * by users through the VM system. 1272 */ 1273 for (i = 0; i < bp->b_npages; i++) 1274 vm_page_test_dirty(bp->b_pages[i]); 1275 1276 /* 1277 * scan forwards for the first page modified 1278 */ 1279 for (i = 0; i < bp->b_npages; i++) { 1280 if (bp->b_pages[i]->dirty) { 1281 break; 1282 } 1283 } 1284 boffset = (i << PAGE_SHIFT); 1285 if (boffset < bp->b_dirtyoff) { 1286 bp->b_dirtyoff = boffset; 1287 } 1288 1289 /* 1290 * scan backwards for the last page modified 1291 */ 1292 for (i = bp->b_npages - 1; i >= 0; --i) { 1293 if (bp->b_pages[i]->dirty) { 1294 break; 1295 } 1296 } 1297 boffset = (i + 1); 1298 offset = boffset + bp->b_pages[0]->pindex; 1299 if (offset >= object->size) 1300 boffset = object->size - bp->b_pages[0]->pindex; 1301 if (bp->b_dirtyend < (boffset << PAGE_SHIFT)) 1302 bp->b_dirtyend = (boffset << PAGE_SHIFT); 1303 } 1304 } 1305 1306 /* 1307 * Get a block given a specified block and offset into a file/device. 1308 */ 1309 struct buf * 1310 getblk(struct vnode * vp, daddr_t blkno, int size, int slpflag, int slptimeo) 1311 { 1312 struct buf *bp; 1313 int s; 1314 struct bufhashhdr *bh; 1315 int maxsize; 1316 static pid_t flushing = 0; 1317 1318 if (vp->v_mount) { 1319 maxsize = vp->v_mount->mnt_stat.f_iosize; 1320 /* 1321 * This happens on mount points. 1322 */ 1323 if (maxsize < size) 1324 maxsize = size; 1325 } else { 1326 maxsize = size; 1327 } 1328 1329 #if !defined(MAX_PERF) 1330 if (size > MAXBSIZE) 1331 panic("getblk: size(%d) > MAXBSIZE(%d)\n", size, MAXBSIZE); 1332 #endif 1333 1334 s = splbio(); 1335 loop: 1336 if (numfreebuffers < lofreebuffers) { 1337 waitfreebuffers(slpflag, slptimeo); 1338 } 1339 1340 if ((bp = gbincore(vp, blkno))) { 1341 if (bp->b_flags & B_BUSY) { 1342 bp->b_flags |= B_WANTED; 1343 if (bp->b_usecount < BUF_MAXUSE) 1344 ++bp->b_usecount; 1345 if (!tsleep(bp, 1346 (PRIBIO + 1) | slpflag, "getblk", slptimeo)) 1347 goto loop; 1348 1349 splx(s); 1350 return (struct buf *) NULL; 1351 } 1352 bp->b_flags |= B_BUSY | B_CACHE; 1353 bremfree(bp); 1354 1355 /* 1356 * check for size inconsistancies (note that they shouldn't happen 1357 * but do when filesystems don't handle the size changes correctly.) 1358 * We are conservative on metadata and don't just extend the buffer 1359 * but write and re-constitute it. 1360 */ 1361 1362 if (bp->b_bcount != size) { 1363 if ((bp->b_flags & B_VMIO) && (size <= bp->b_kvasize)) { 1364 allocbuf(bp, size); 1365 } else { 1366 bp->b_flags |= B_NOCACHE; 1367 VOP_BWRITE(bp); 1368 goto loop; 1369 } 1370 } 1371 1372 if (bp->b_usecount < BUF_MAXUSE) 1373 ++bp->b_usecount; 1374 splx(s); 1375 return (bp); 1376 } else { 1377 vm_object_t obj; 1378 1379 if ((bp = getnewbuf(vp, slpflag, slptimeo, size, maxsize)) == 0) { 1380 if (slpflag || slptimeo) { 1381 splx(s); 1382 return NULL; 1383 } 1384 goto loop; 1385 } 1386 1387 /* 1388 * This code is used to make sure that a buffer is not 1389 * created while the getnewbuf routine is blocked. 1390 * Normally the vnode is locked so this isn't a problem. 1391 * VBLK type I/O requests, however, don't lock the vnode. 1392 */ 1393 if (!VOP_ISLOCKED(vp) && gbincore(vp, blkno)) { 1394 bp->b_flags |= B_INVAL; 1395 brelse(bp); 1396 goto loop; 1397 } 1398 1399 /* 1400 * Insert the buffer into the hash, so that it can 1401 * be found by incore. 1402 */ 1403 bp->b_blkno = bp->b_lblkno = blkno; 1404 bgetvp(vp, bp); 1405 LIST_REMOVE(bp, b_hash); 1406 bh = BUFHASH(vp, blkno); 1407 LIST_INSERT_HEAD(bh, bp, b_hash); 1408 1409 if ((obj = vp->v_object) && (vp->v_flag & VVMIO)) { 1410 bp->b_flags |= (B_VMIO | B_CACHE); 1411 #if defined(VFS_BIO_DEBUG) 1412 if (vp->v_type != VREG && vp->v_type != VBLK) 1413 printf("getblk: vmioing file type %d???\n", vp->v_type); 1414 #endif 1415 } else { 1416 bp->b_flags &= ~B_VMIO; 1417 } 1418 splx(s); 1419 1420 allocbuf(bp, size); 1421 #ifdef PC98 1422 /* 1423 * 1024byte/sector support 1424 */ 1425 #define B_XXX2 0x8000000 1426 if (vp->v_flag & 0x10000) bp->b_flags |= B_XXX2; 1427 #endif 1428 return (bp); 1429 } 1430 } 1431 1432 /* 1433 * Get an empty, disassociated buffer of given size. 1434 */ 1435 struct buf * 1436 geteblk(int size) 1437 { 1438 struct buf *bp; 1439 int s; 1440 1441 s = splbio(); 1442 while ((bp = getnewbuf(0, 0, 0, size, MAXBSIZE)) == 0); 1443 splx(s); 1444 allocbuf(bp, size); 1445 bp->b_flags |= B_INVAL; 1446 return (bp); 1447 } 1448 1449 1450 /* 1451 * This code constitutes the buffer memory from either anonymous system 1452 * memory (in the case of non-VMIO operations) or from an associated 1453 * VM object (in the case of VMIO operations). 1454 * 1455 * Note that this code is tricky, and has many complications to resolve 1456 * deadlock or inconsistant data situations. Tread lightly!!! 1457 * 1458 * Modify the length of a buffer's underlying buffer storage without 1459 * destroying information (unless, of course the buffer is shrinking). 1460 */ 1461 int 1462 allocbuf(struct buf * bp, int size) 1463 { 1464 1465 int s; 1466 int newbsize, mbsize; 1467 int i; 1468 1469 #if !defined(MAX_PERF) 1470 if (!(bp->b_flags & B_BUSY)) 1471 panic("allocbuf: buffer not busy"); 1472 1473 if (bp->b_kvasize < size) 1474 panic("allocbuf: buffer too small"); 1475 #endif 1476 1477 if ((bp->b_flags & B_VMIO) == 0) { 1478 caddr_t origbuf; 1479 int origbufsize; 1480 /* 1481 * Just get anonymous memory from the kernel 1482 */ 1483 mbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 1484 #if !defined(NO_B_MALLOC) 1485 if (bp->b_flags & B_MALLOC) 1486 newbsize = mbsize; 1487 else 1488 #endif 1489 newbsize = round_page(size); 1490 1491 if (newbsize < bp->b_bufsize) { 1492 #if !defined(NO_B_MALLOC) 1493 /* 1494 * malloced buffers are not shrunk 1495 */ 1496 if (bp->b_flags & B_MALLOC) { 1497 if (newbsize) { 1498 bp->b_bcount = size; 1499 } else { 1500 free(bp->b_data, M_BIOBUF); 1501 bufspace -= bp->b_bufsize; 1502 bufmallocspace -= bp->b_bufsize; 1503 bp->b_data = bp->b_kvabase; 1504 bp->b_bufsize = 0; 1505 bp->b_bcount = 0; 1506 bp->b_flags &= ~B_MALLOC; 1507 } 1508 return 1; 1509 } 1510 #endif 1511 vm_hold_free_pages( 1512 bp, 1513 (vm_offset_t) bp->b_data + newbsize, 1514 (vm_offset_t) bp->b_data + bp->b_bufsize); 1515 } else if (newbsize > bp->b_bufsize) { 1516 #if !defined(NO_B_MALLOC) 1517 /* 1518 * We only use malloced memory on the first allocation. 1519 * and revert to page-allocated memory when the buffer grows. 1520 */ 1521 if ( (bufmallocspace < maxbufmallocspace) && 1522 (bp->b_bufsize == 0) && 1523 (mbsize <= PAGE_SIZE/2)) { 1524 1525 bp->b_data = malloc(mbsize, M_BIOBUF, M_WAITOK); 1526 bp->b_bufsize = mbsize; 1527 bp->b_bcount = size; 1528 bp->b_flags |= B_MALLOC; 1529 bufspace += mbsize; 1530 bufmallocspace += mbsize; 1531 return 1; 1532 } 1533 #endif 1534 origbuf = NULL; 1535 origbufsize = 0; 1536 #if !defined(NO_B_MALLOC) 1537 /* 1538 * If the buffer is growing on it's other-than-first allocation, 1539 * then we revert to the page-allocation scheme. 1540 */ 1541 if (bp->b_flags & B_MALLOC) { 1542 origbuf = bp->b_data; 1543 origbufsize = bp->b_bufsize; 1544 bp->b_data = bp->b_kvabase; 1545 bufspace -= bp->b_bufsize; 1546 bufmallocspace -= bp->b_bufsize; 1547 bp->b_bufsize = 0; 1548 bp->b_flags &= ~B_MALLOC; 1549 newbsize = round_page(newbsize); 1550 } 1551 #endif 1552 vm_hold_load_pages( 1553 bp, 1554 (vm_offset_t) bp->b_data + bp->b_bufsize, 1555 (vm_offset_t) bp->b_data + newbsize); 1556 #if !defined(NO_B_MALLOC) 1557 if (origbuf) { 1558 bcopy(origbuf, bp->b_data, origbufsize); 1559 free(origbuf, M_BIOBUF); 1560 } 1561 #endif 1562 } 1563 } else { 1564 vm_page_t m; 1565 int desiredpages; 1566 1567 newbsize = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); 1568 desiredpages = (round_page(newbsize) >> PAGE_SHIFT); 1569 1570 #if !defined(NO_B_MALLOC) 1571 if (bp->b_flags & B_MALLOC) 1572 panic("allocbuf: VMIO buffer can't be malloced"); 1573 #endif 1574 1575 if (newbsize < bp->b_bufsize) { 1576 if (desiredpages < bp->b_npages) { 1577 for (i = desiredpages; i < bp->b_npages; i++) { 1578 /* 1579 * the page is not freed here -- it 1580 * is the responsibility of vnode_pager_setsize 1581 */ 1582 m = bp->b_pages[i]; 1583 #if defined(DIAGNOSTIC) 1584 if (m == bogus_page) 1585 panic("allocbuf: bogus page found"); 1586 #endif 1587 s = splvm(); 1588 while ((m->flags & PG_BUSY) || (m->busy != 0)) { 1589 m->flags |= PG_WANTED; 1590 tsleep(m, PVM, "biodep", 0); 1591 } 1592 splx(s); 1593 1594 bp->b_pages[i] = NULL; 1595 vm_page_unwire(m); 1596 } 1597 pmap_qremove((vm_offset_t) trunc_page(bp->b_data) + 1598 (desiredpages << PAGE_SHIFT), (bp->b_npages - desiredpages)); 1599 bp->b_npages = desiredpages; 1600 } 1601 } else if (newbsize > bp->b_bufsize) { 1602 vm_object_t obj; 1603 vm_offset_t tinc, toff; 1604 vm_ooffset_t off; 1605 vm_pindex_t objoff; 1606 int pageindex, curbpnpages; 1607 struct vnode *vp; 1608 int bsize; 1609 1610 vp = bp->b_vp; 1611 1612 if (vp->v_type == VBLK) 1613 bsize = DEV_BSIZE; 1614 else 1615 bsize = vp->v_mount->mnt_stat.f_iosize; 1616 1617 if (bp->b_npages < desiredpages) { 1618 obj = vp->v_object; 1619 tinc = PAGE_SIZE; 1620 if (tinc > bsize) 1621 tinc = bsize; 1622 off = (vm_ooffset_t) bp->b_lblkno * bsize; 1623 curbpnpages = bp->b_npages; 1624 doretry: 1625 bp->b_flags |= B_CACHE; 1626 bp->b_validoff = bp->b_validend = 0; 1627 for (toff = 0; toff < newbsize; toff += tinc) { 1628 int bytesinpage; 1629 1630 pageindex = toff >> PAGE_SHIFT; 1631 objoff = OFF_TO_IDX(off + toff); 1632 if (pageindex < curbpnpages) { 1633 1634 m = bp->b_pages[pageindex]; 1635 #ifdef VFS_BIO_DIAG 1636 if (m->pindex != objoff) 1637 panic("allocbuf: page changed offset??!!!?"); 1638 #endif 1639 bytesinpage = tinc; 1640 if (tinc > (newbsize - toff)) 1641 bytesinpage = newbsize - toff; 1642 if (bp->b_flags & B_CACHE) 1643 vfs_buf_set_valid(bp, off, toff, bytesinpage, m); 1644 continue; 1645 } 1646 m = vm_page_lookup(obj, objoff); 1647 if (!m) { 1648 m = vm_page_alloc(obj, objoff, VM_ALLOC_NORMAL); 1649 if (!m) { 1650 VM_WAIT; 1651 goto doretry; 1652 } 1653 /* 1654 * Normally it is unwise to clear PG_BUSY without 1655 * PAGE_WAKEUP -- but it is okay here, as there is 1656 * no chance for blocking between here and vm_page_alloc 1657 */ 1658 m->flags &= ~PG_BUSY; 1659 vm_page_wire(m); 1660 bp->b_flags &= ~B_CACHE; 1661 } else if (m->flags & PG_BUSY) { 1662 s = splvm(); 1663 if (m->flags & PG_BUSY) { 1664 m->flags |= PG_WANTED; 1665 tsleep(m, PVM, "pgtblk", 0); 1666 } 1667 splx(s); 1668 goto doretry; 1669 } else { 1670 if ((curproc != pageproc) && 1671 ((m->queue - m->pc) == PQ_CACHE) && 1672 ((cnt.v_free_count + cnt.v_cache_count) < 1673 (cnt.v_free_min + cnt.v_cache_min))) { 1674 pagedaemon_wakeup(); 1675 } 1676 bytesinpage = tinc; 1677 if (tinc > (newbsize - toff)) 1678 bytesinpage = newbsize - toff; 1679 if (bp->b_flags & B_CACHE) 1680 vfs_buf_set_valid(bp, off, toff, bytesinpage, m); 1681 vm_page_wire(m); 1682 } 1683 bp->b_pages[pageindex] = m; 1684 curbpnpages = pageindex + 1; 1685 } 1686 if (vp->v_tag == VT_NFS) { 1687 if (bp->b_dirtyend > 0) { 1688 bp->b_validoff = min(bp->b_validoff, bp->b_dirtyoff); 1689 bp->b_validend = max(bp->b_validend, bp->b_dirtyend); 1690 } 1691 if (bp->b_validend == 0) 1692 bp->b_flags &= ~B_CACHE; 1693 } 1694 bp->b_data = (caddr_t) trunc_page(bp->b_data); 1695 bp->b_npages = curbpnpages; 1696 pmap_qenter((vm_offset_t) bp->b_data, 1697 bp->b_pages, bp->b_npages); 1698 ((vm_offset_t) bp->b_data) |= off & PAGE_MASK; 1699 } 1700 } 1701 } 1702 if (bp->b_flags & B_VMIO) 1703 vmiospace += (newbsize - bp->b_bufsize); 1704 bufspace += (newbsize - bp->b_bufsize); 1705 bp->b_bufsize = newbsize; 1706 bp->b_bcount = size; 1707 return 1; 1708 } 1709 1710 /* 1711 * Wait for buffer I/O completion, returning error status. 1712 */ 1713 int 1714 biowait(register struct buf * bp) 1715 { 1716 int s; 1717 1718 s = splbio(); 1719 while ((bp->b_flags & B_DONE) == 0) 1720 tsleep(bp, PRIBIO, "biowait", 0); 1721 splx(s); 1722 if (bp->b_flags & B_EINTR) { 1723 bp->b_flags &= ~B_EINTR; 1724 return (EINTR); 1725 } 1726 if (bp->b_flags & B_ERROR) { 1727 return (bp->b_error ? bp->b_error : EIO); 1728 } else { 1729 return (0); 1730 } 1731 } 1732 1733 /* 1734 * Finish I/O on a buffer, calling an optional function. 1735 * This is usually called from interrupt level, so process blocking 1736 * is not *a good idea*. 1737 */ 1738 void 1739 biodone(register struct buf * bp) 1740 { 1741 int s; 1742 1743 s = splbio(); 1744 1745 #if !defined(MAX_PERF) 1746 if (!(bp->b_flags & B_BUSY)) 1747 panic("biodone: buffer not busy"); 1748 #endif 1749 1750 if (bp->b_flags & B_DONE) { 1751 splx(s); 1752 #if !defined(MAX_PERF) 1753 printf("biodone: buffer already done\n"); 1754 #endif 1755 return; 1756 } 1757 bp->b_flags |= B_DONE; 1758 1759 if ((bp->b_flags & B_READ) == 0) { 1760 vwakeup(bp); 1761 } 1762 #ifdef BOUNCE_BUFFERS 1763 if (bp->b_flags & B_BOUNCE) 1764 vm_bounce_free(bp); 1765 #endif 1766 1767 /* call optional completion function if requested */ 1768 if (bp->b_flags & B_CALL) { 1769 bp->b_flags &= ~B_CALL; 1770 (*bp->b_iodone) (bp); 1771 splx(s); 1772 return; 1773 } 1774 if (bp->b_flags & B_VMIO) { 1775 int i, resid; 1776 vm_ooffset_t foff; 1777 vm_page_t m; 1778 vm_object_t obj; 1779 int iosize; 1780 struct vnode *vp = bp->b_vp; 1781 1782 if (vp->v_type == VBLK) 1783 foff = (vm_ooffset_t) DEV_BSIZE * bp->b_lblkno; 1784 else 1785 foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 1786 obj = vp->v_object; 1787 #if !defined(MAX_PERF) 1788 if (!obj) { 1789 panic("biodone: no object"); 1790 } 1791 #endif 1792 #if defined(VFS_BIO_DEBUG) 1793 if (obj->paging_in_progress < bp->b_npages) { 1794 printf("biodone: paging in progress(%d) < bp->b_npages(%d)\n", 1795 obj->paging_in_progress, bp->b_npages); 1796 } 1797 #endif 1798 iosize = bp->b_bufsize; 1799 for (i = 0; i < bp->b_npages; i++) { 1800 int bogusflag = 0; 1801 m = bp->b_pages[i]; 1802 if (m == bogus_page) { 1803 bogusflag = 1; 1804 m = vm_page_lookup(obj, OFF_TO_IDX(foff)); 1805 if (!m) { 1806 #if defined(VFS_BIO_DEBUG) 1807 printf("biodone: page disappeared\n"); 1808 #endif 1809 --obj->paging_in_progress; 1810 continue; 1811 } 1812 bp->b_pages[i] = m; 1813 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 1814 } 1815 #if defined(VFS_BIO_DEBUG) 1816 if (OFF_TO_IDX(foff) != m->pindex) { 1817 printf("biodone: foff(%d)/m->pindex(%d) mismatch\n", foff, m->pindex); 1818 } 1819 #endif 1820 resid = IDX_TO_OFF(m->pindex + 1) - foff; 1821 if (resid > iosize) 1822 resid = iosize; 1823 /* 1824 * In the write case, the valid and clean bits are 1825 * already changed correctly, so we only need to do this 1826 * here in the read case. 1827 */ 1828 if ((bp->b_flags & B_READ) && !bogusflag && resid > 0) { 1829 vfs_page_set_valid(bp, foff, i, m); 1830 } 1831 1832 /* 1833 * when debugging new filesystems or buffer I/O methods, this 1834 * is the most common error that pops up. if you see this, you 1835 * have not set the page busy flag correctly!!! 1836 */ 1837 if (m->busy == 0) { 1838 #if !defined(MAX_PERF) 1839 printf("biodone: page busy < 0, " 1840 "pindex: %d, foff: 0x(%x,%x), " 1841 "resid: %d, index: %d\n", 1842 (int) m->pindex, (int)(foff >> 32), 1843 (int) foff & 0xffffffff, resid, i); 1844 #endif 1845 if (vp->v_type != VBLK) 1846 #if !defined(MAX_PERF) 1847 printf(" iosize: %ld, lblkno: %d, flags: 0x%lx, npages: %d\n", 1848 bp->b_vp->v_mount->mnt_stat.f_iosize, 1849 (int) bp->b_lblkno, 1850 bp->b_flags, bp->b_npages); 1851 else 1852 printf(" VDEV, lblkno: %d, flags: 0x%lx, npages: %d\n", 1853 (int) bp->b_lblkno, 1854 bp->b_flags, bp->b_npages); 1855 printf(" valid: 0x%x, dirty: 0x%x, wired: %d\n", 1856 m->valid, m->dirty, m->wire_count); 1857 #endif 1858 panic("biodone: page busy < 0\n"); 1859 } 1860 --m->busy; 1861 if ((m->busy == 0) && (m->flags & PG_WANTED)) { 1862 m->flags &= ~PG_WANTED; 1863 wakeup(m); 1864 } 1865 --obj->paging_in_progress; 1866 foff += resid; 1867 iosize -= resid; 1868 } 1869 if (obj && obj->paging_in_progress == 0 && 1870 (obj->flags & OBJ_PIPWNT)) { 1871 obj->flags &= ~OBJ_PIPWNT; 1872 wakeup(obj); 1873 } 1874 } 1875 /* 1876 * For asynchronous completions, release the buffer now. The brelse 1877 * checks for B_WANTED and will do the wakeup there if necessary - so 1878 * no need to do a wakeup here in the async case. 1879 */ 1880 1881 if (bp->b_flags & B_ASYNC) { 1882 if ((bp->b_flags & B_ORDERED) == 0) { 1883 if ((bp->b_flags & (B_NOCACHE | B_INVAL | B_ERROR | B_RELBUF)) != 0) 1884 brelse(bp); 1885 else 1886 bqrelse(bp); 1887 } 1888 } else { 1889 bp->b_flags &= ~B_WANTED; 1890 wakeup(bp); 1891 } 1892 splx(s); 1893 } 1894 1895 int 1896 count_lock_queue() 1897 { 1898 int count; 1899 struct buf *bp; 1900 1901 count = 0; 1902 for (bp = TAILQ_FIRST(&bufqueues[QUEUE_LOCKED]); 1903 bp != NULL; 1904 bp = TAILQ_NEXT(bp, b_freelist)) 1905 count++; 1906 return (count); 1907 } 1908 1909 int vfs_update_interval = 30; 1910 1911 static void 1912 vfs_update() 1913 { 1914 while (1) { 1915 tsleep(&vfs_update_wakeup, PUSER, "update", 1916 hz * vfs_update_interval); 1917 vfs_update_wakeup = 0; 1918 sync(curproc, NULL, NULL); 1919 } 1920 } 1921 1922 static int 1923 sysctl_kern_updateinterval SYSCTL_HANDLER_ARGS 1924 { 1925 int error = sysctl_handle_int(oidp, 1926 oidp->oid_arg1, oidp->oid_arg2, req); 1927 if (!error) 1928 wakeup(&vfs_update_wakeup); 1929 return error; 1930 } 1931 1932 SYSCTL_PROC(_kern, KERN_UPDATEINTERVAL, update, CTLTYPE_INT|CTLFLAG_RW, 1933 &vfs_update_interval, 0, sysctl_kern_updateinterval, "I", ""); 1934 1935 1936 /* 1937 * This routine is called in lieu of iodone in the case of 1938 * incomplete I/O. This keeps the busy status for pages 1939 * consistant. 1940 */ 1941 void 1942 vfs_unbusy_pages(struct buf * bp) 1943 { 1944 int i; 1945 1946 if (bp->b_flags & B_VMIO) { 1947 struct vnode *vp = bp->b_vp; 1948 vm_object_t obj = vp->v_object; 1949 vm_ooffset_t foff; 1950 1951 foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 1952 1953 for (i = 0; i < bp->b_npages; i++) { 1954 vm_page_t m = bp->b_pages[i]; 1955 1956 if (m == bogus_page) { 1957 m = vm_page_lookup(obj, OFF_TO_IDX(foff) + i); 1958 #if !defined(MAX_PERF) 1959 if (!m) { 1960 panic("vfs_unbusy_pages: page missing\n"); 1961 } 1962 #endif 1963 bp->b_pages[i] = m; 1964 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 1965 } 1966 --obj->paging_in_progress; 1967 --m->busy; 1968 if ((m->busy == 0) && (m->flags & PG_WANTED)) { 1969 m->flags &= ~PG_WANTED; 1970 wakeup(m); 1971 } 1972 } 1973 if (obj->paging_in_progress == 0 && 1974 (obj->flags & OBJ_PIPWNT)) { 1975 obj->flags &= ~OBJ_PIPWNT; 1976 wakeup(obj); 1977 } 1978 } 1979 } 1980 1981 /* 1982 * Set NFS' b_validoff and b_validend fields from the valid bits 1983 * of a page. If the consumer is not NFS, and the page is not 1984 * valid for the entire range, clear the B_CACHE flag to force 1985 * the consumer to re-read the page. 1986 */ 1987 static void 1988 vfs_buf_set_valid(struct buf *bp, 1989 vm_ooffset_t foff, vm_offset_t off, vm_offset_t size, 1990 vm_page_t m) 1991 { 1992 if (bp->b_vp->v_tag == VT_NFS) { 1993 vm_offset_t svalid, evalid; 1994 int validbits = m->valid; 1995 1996 /* 1997 * This only bothers with the first valid range in the 1998 * page. 1999 */ 2000 svalid = off; 2001 while (validbits && !(validbits & 1)) { 2002 svalid += DEV_BSIZE; 2003 validbits >>= 1; 2004 } 2005 evalid = svalid; 2006 while (validbits & 1) { 2007 evalid += DEV_BSIZE; 2008 validbits >>= 1; 2009 } 2010 /* 2011 * Make sure this range is contiguous with the range 2012 * built up from previous pages. If not, then we will 2013 * just use the range from the previous pages. 2014 */ 2015 if (svalid == bp->b_validend) { 2016 bp->b_validoff = min(bp->b_validoff, svalid); 2017 bp->b_validend = max(bp->b_validend, evalid); 2018 } 2019 } else if (!vm_page_is_valid(m, 2020 (vm_offset_t) ((foff + off) & PAGE_MASK), 2021 size)) { 2022 bp->b_flags &= ~B_CACHE; 2023 } 2024 } 2025 2026 /* 2027 * Set the valid bits in a page, taking care of the b_validoff, 2028 * b_validend fields which NFS uses to optimise small reads. Off is 2029 * the offset within the file and pageno is the page index within the buf. 2030 */ 2031 static void 2032 vfs_page_set_valid(struct buf *bp, vm_ooffset_t off, int pageno, vm_page_t m) 2033 { 2034 struct vnode *vp = bp->b_vp; 2035 vm_ooffset_t soff, eoff; 2036 2037 soff = off; 2038 eoff = off + min(PAGE_SIZE, bp->b_bufsize); 2039 vm_page_set_invalid(m, 2040 (vm_offset_t) (soff & PAGE_MASK), 2041 (vm_offset_t) (eoff - soff)); 2042 if (vp->v_tag == VT_NFS) { 2043 vm_ooffset_t sv, ev; 2044 off = off - pageno * PAGE_SIZE; 2045 sv = off + ((bp->b_validoff + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1)); 2046 ev = off + (bp->b_validend & ~(DEV_BSIZE - 1)); 2047 soff = max(sv, soff); 2048 eoff = min(ev, eoff); 2049 } 2050 if (eoff > soff) 2051 vm_page_set_validclean(m, 2052 (vm_offset_t) (soff & PAGE_MASK), 2053 (vm_offset_t) (eoff - soff)); 2054 } 2055 2056 /* 2057 * This routine is called before a device strategy routine. 2058 * It is used to tell the VM system that paging I/O is in 2059 * progress, and treat the pages associated with the buffer 2060 * almost as being PG_BUSY. Also the object paging_in_progress 2061 * flag is handled to make sure that the object doesn't become 2062 * inconsistant. 2063 */ 2064 void 2065 vfs_busy_pages(struct buf * bp, int clear_modify) 2066 { 2067 int i; 2068 2069 if (bp->b_flags & B_VMIO) { 2070 struct vnode *vp = bp->b_vp; 2071 vm_object_t obj = vp->v_object; 2072 vm_ooffset_t foff; 2073 2074 if (vp->v_type == VBLK) 2075 foff = (vm_ooffset_t) DEV_BSIZE * bp->b_lblkno; 2076 else 2077 foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 2078 vfs_setdirty(bp); 2079 for (i = 0; i < bp->b_npages; i++, foff += PAGE_SIZE) { 2080 vm_page_t m = bp->b_pages[i]; 2081 2082 if ((bp->b_flags & B_CLUSTER) == 0) { 2083 obj->paging_in_progress++; 2084 m->busy++; 2085 } 2086 vm_page_protect(m, VM_PROT_NONE); 2087 if (clear_modify) 2088 vfs_page_set_valid(bp, foff, i, m); 2089 else if (bp->b_bcount >= PAGE_SIZE) { 2090 if (m->valid && (bp->b_flags & B_CACHE) == 0) { 2091 bp->b_pages[i] = bogus_page; 2092 pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages); 2093 } 2094 } 2095 } 2096 } 2097 } 2098 2099 /* 2100 * Tell the VM system that the pages associated with this buffer 2101 * are clean. This is used for delayed writes where the data is 2102 * going to go to disk eventually without additional VM intevention. 2103 */ 2104 void 2105 vfs_clean_pages(struct buf * bp) 2106 { 2107 int i; 2108 2109 if (bp->b_flags & B_VMIO) { 2110 struct vnode *vp = bp->b_vp; 2111 vm_object_t obj = vp->v_object; 2112 vm_ooffset_t foff; 2113 2114 if (vp->v_type == VBLK) 2115 foff = (vm_ooffset_t) DEV_BSIZE * bp->b_lblkno; 2116 else 2117 foff = (vm_ooffset_t) vp->v_mount->mnt_stat.f_iosize * bp->b_lblkno; 2118 for (i = 0; i < bp->b_npages; i++, foff += PAGE_SIZE) { 2119 vm_page_t m = bp->b_pages[i]; 2120 2121 vfs_page_set_valid(bp, foff, i, m); 2122 } 2123 } 2124 } 2125 2126 void 2127 vfs_bio_clrbuf(struct buf *bp) { 2128 int i; 2129 if( bp->b_flags & B_VMIO) { 2130 if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE)) { 2131 int mask; 2132 mask = 0; 2133 for(i=0;i<bp->b_bufsize;i+=DEV_BSIZE) 2134 mask |= (1 << (i/DEV_BSIZE)); 2135 if( bp->b_pages[0]->valid != mask) { 2136 bzero(bp->b_data, bp->b_bufsize); 2137 } 2138 bp->b_pages[0]->valid = mask; 2139 bp->b_resid = 0; 2140 return; 2141 } 2142 for(i=0;i<bp->b_npages;i++) { 2143 if( bp->b_pages[i]->valid == VM_PAGE_BITS_ALL) 2144 continue; 2145 if( bp->b_pages[i]->valid == 0) { 2146 if ((bp->b_pages[i]->flags & PG_ZERO) == 0) { 2147 bzero(bp->b_data + (i << PAGE_SHIFT), PAGE_SIZE); 2148 } 2149 } else { 2150 int j; 2151 for(j=0;j<PAGE_SIZE/DEV_BSIZE;j++) { 2152 if( (bp->b_pages[i]->valid & (1<<j)) == 0) 2153 bzero(bp->b_data + (i << PAGE_SHIFT) + j * DEV_BSIZE, DEV_BSIZE); 2154 } 2155 } 2156 /* bp->b_pages[i]->valid = VM_PAGE_BITS_ALL; */ 2157 } 2158 bp->b_resid = 0; 2159 } else { 2160 clrbuf(bp); 2161 } 2162 } 2163 2164 /* 2165 * vm_hold_load_pages and vm_hold_unload pages get pages into 2166 * a buffers address space. The pages are anonymous and are 2167 * not associated with a file object. 2168 */ 2169 void 2170 vm_hold_load_pages(struct buf * bp, vm_offset_t from, vm_offset_t to) 2171 { 2172 vm_offset_t pg; 2173 vm_page_t p; 2174 int index; 2175 2176 to = round_page(to); 2177 from = round_page(from); 2178 index = (from - trunc_page(bp->b_data)) >> PAGE_SHIFT; 2179 2180 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 2181 2182 tryagain: 2183 2184 p = vm_page_alloc(kernel_object, ((pg - VM_MIN_KERNEL_ADDRESS) >> PAGE_SHIFT), 2185 VM_ALLOC_NORMAL); 2186 if (!p) { 2187 VM_WAIT; 2188 goto tryagain; 2189 } 2190 vm_page_wire(p); 2191 pmap_kenter(pg, VM_PAGE_TO_PHYS(p)); 2192 bp->b_pages[index] = p; 2193 PAGE_WAKEUP(p); 2194 } 2195 bp->b_npages = to >> PAGE_SHIFT; 2196 } 2197 2198 void 2199 vm_hold_free_pages(struct buf * bp, vm_offset_t from, vm_offset_t to) 2200 { 2201 vm_offset_t pg; 2202 vm_page_t p; 2203 int index; 2204 2205 from = round_page(from); 2206 to = round_page(to); 2207 index = (from - trunc_page(bp->b_data)) >> PAGE_SHIFT; 2208 2209 for (pg = from; pg < to; pg += PAGE_SIZE, index++) { 2210 p = bp->b_pages[index]; 2211 if (p && (index < bp->b_npages)) { 2212 #if !defined(MAX_PERF) 2213 if (p->busy) { 2214 printf("vm_hold_free_pages: blkno: %d, lblkno: %d\n", 2215 bp->b_blkno, bp->b_lblkno); 2216 } 2217 #endif 2218 bp->b_pages[index] = NULL; 2219 pmap_kremove(pg); 2220 vm_page_unwire(p); 2221 vm_page_free(p); 2222 } 2223 } 2224 bp->b_npages = from >> PAGE_SHIFT; 2225 } 2226 2227 2228 #include "opt_ddb.h" 2229 #ifdef DDB 2230 #include <ddb/ddb.h> 2231 2232 DB_SHOW_COMMAND(buffer, db_show_buffer) 2233 { 2234 /* get args */ 2235 struct buf *bp = (struct buf *)addr; 2236 2237 if (!have_addr) { 2238 db_printf("usage: show buffer <addr>\n"); 2239 return; 2240 } 2241 2242 db_printf("b_proc = %p,\nb_flags = 0x%b\n", (void *)bp->b_proc, 2243 bp->b_flags, "\20\40bounce\37cluster\36vmio\35ram\34ordered" 2244 "\33paging\32xxx\31writeinprog\30wanted\27relbuf\26tape" 2245 "\25read\24raw\23phys\22clusterok\21malloc\20nocache" 2246 "\17locked\16inval\15gathered\14error\13eintr\12done\11dirty" 2247 "\10delwri\7call\6cache\5busy\4bad\3async\2needcommit\1age"); 2248 db_printf("b_error = %d, b_bufsize = %ld, b_bcount = %ld, " 2249 "b_resid = %ld\nb_dev = 0x%x, b_un.b_addr = %p, " 2250 "b_blkno = %d, b_pblkno = %d\n", 2251 bp->b_error, bp->b_bufsize, bp->b_bcount, bp->b_resid, 2252 bp->b_dev, bp->b_un.b_addr, bp->b_blkno, bp->b_pblkno); 2253 } 2254 #endif /* DDB */ 2255