1 /*- 2 * Copyright (c) 1993 3 * The Regents of the University of California. All rights reserved. 4 * Modifications/enhancements: 5 * Copyright (c) 1995 John S. Dyson. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94 36 * $FreeBSD$ 37 */ 38 39 #include "opt_debug_cluster.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/kernel.h> 44 #include <sys/proc.h> 45 #include <sys/bio.h> 46 #include <sys/buf.h> 47 #include <sys/vnode.h> 48 #include <sys/malloc.h> 49 #include <sys/mount.h> 50 #include <sys/resourcevar.h> 51 #include <vm/vm.h> 52 #include <vm/vm_object.h> 53 #include <vm/vm_page.h> 54 #include <sys/sysctl.h> 55 56 #if defined(CLUSTERDEBUG) 57 #include <sys/sysctl.h> 58 static int rcluster= 0; 59 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, ""); 60 #endif 61 62 static MALLOC_DEFINE(M_SEGMENT, "cluster_save buffer", "cluster_save buffer"); 63 64 static struct cluster_save * 65 cluster_collectbufs __P((struct vnode *vp, struct buf *last_bp)); 66 static struct buf * 67 cluster_rbuild __P((struct vnode *vp, u_quad_t filesize, daddr_t lbn, 68 daddr_t blkno, long size, int run, struct buf *fbp)); 69 70 static int write_behind = 1; 71 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, ""); 72 73 extern vm_page_t bogus_page; 74 75 extern int cluster_pbuf_freecnt; 76 77 /* 78 * Maximum number of blocks for read-ahead. 79 */ 80 #define MAXRA 32 81 82 /* 83 * This replaces bread. 84 */ 85 int 86 cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp) 87 struct vnode *vp; 88 u_quad_t filesize; 89 daddr_t lblkno; 90 long size; 91 struct ucred *cred; 92 long totread; 93 int seqcount; 94 struct buf **bpp; 95 { 96 struct buf *bp, *rbp, *reqbp; 97 daddr_t blkno, origblkno; 98 int error, num_ra; 99 int i; 100 int maxra, racluster; 101 long origtotread; 102 103 error = 0; 104 105 /* 106 * Try to limit the amount of read-ahead by a few 107 * ad-hoc parameters. This needs work!!! 108 */ 109 racluster = vp->v_mount->mnt_iosize_max / size; 110 maxra = 2 * racluster + (totread / size); 111 if (maxra > MAXRA) 112 maxra = MAXRA; 113 if (maxra > nbuf/8) 114 maxra = nbuf/8; 115 116 /* 117 * get the requested block 118 */ 119 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0); 120 origblkno = lblkno; 121 origtotread = totread; 122 123 /* 124 * if it is in the cache, then check to see if the reads have been 125 * sequential. If they have, then try some read-ahead, otherwise 126 * back-off on prospective read-aheads. 127 */ 128 if (bp->b_flags & B_CACHE) { 129 if (!seqcount) { 130 return 0; 131 } else if ((bp->b_flags & B_RAM) == 0) { 132 return 0; 133 } else { 134 int s; 135 struct buf *tbp; 136 bp->b_flags &= ~B_RAM; 137 /* 138 * We do the spl here so that there is no window 139 * between the incore and the b_usecount increment 140 * below. We opt to keep the spl out of the loop 141 * for efficiency. 142 */ 143 s = splbio(); 144 for (i = 1; i < maxra; i++) { 145 146 if (!(tbp = incore(vp, lblkno+i))) { 147 break; 148 } 149 150 /* 151 * Set another read-ahead mark so we know 152 * to check again. 153 */ 154 if (((i % racluster) == (racluster - 1)) || 155 (i == (maxra - 1))) 156 tbp->b_flags |= B_RAM; 157 } 158 splx(s); 159 if (i >= maxra) { 160 return 0; 161 } 162 lblkno += i; 163 } 164 reqbp = bp = NULL; 165 } else { 166 off_t firstread = bp->b_offset; 167 168 KASSERT(bp->b_offset != NOOFFSET, 169 ("cluster_read: no buffer offset")); 170 if (firstread + totread > filesize) 171 totread = filesize - firstread; 172 if (totread > size) { 173 int nblks = 0; 174 int ncontigafter; 175 while (totread > 0) { 176 nblks++; 177 totread -= size; 178 } 179 if (nblks == 1) 180 goto single_block_read; 181 if (nblks > racluster) 182 nblks = racluster; 183 184 error = VOP_BMAP(vp, lblkno, NULL, 185 &blkno, &ncontigafter, NULL); 186 if (error) 187 goto single_block_read; 188 if (blkno == -1) 189 goto single_block_read; 190 if (ncontigafter == 0) 191 goto single_block_read; 192 if (ncontigafter + 1 < nblks) 193 nblks = ncontigafter + 1; 194 195 bp = cluster_rbuild(vp, filesize, lblkno, 196 blkno, size, nblks, bp); 197 lblkno += (bp->b_bufsize / size); 198 } else { 199 single_block_read: 200 /* 201 * if it isn't in the cache, then get a chunk from 202 * disk if sequential, otherwise just get the block. 203 */ 204 bp->b_flags |= B_RAM; 205 bp->b_iocmd = BIO_READ; 206 lblkno += 1; 207 } 208 } 209 210 /* 211 * if we have been doing sequential I/O, then do some read-ahead 212 */ 213 rbp = NULL; 214 if (seqcount && (lblkno < (origblkno + seqcount))) { 215 /* 216 * we now build the read-ahead buffer if it is desirable. 217 */ 218 if (((u_quad_t)(lblkno + 1) * size) <= filesize && 219 !(error = VOP_BMAP(vp, lblkno, NULL, &blkno, &num_ra, NULL)) && 220 blkno != -1) { 221 int nblksread; 222 int ntoread = num_ra + 1; 223 nblksread = (origtotread + size - 1) / size; 224 if (seqcount < nblksread) 225 seqcount = nblksread; 226 if (seqcount < ntoread) 227 ntoread = seqcount; 228 if (num_ra) { 229 rbp = cluster_rbuild(vp, filesize, lblkno, 230 blkno, size, ntoread, NULL); 231 } else { 232 rbp = getblk(vp, lblkno, size, 0, 0); 233 rbp->b_flags |= B_ASYNC | B_RAM; 234 rbp->b_iocmd = BIO_READ; 235 rbp->b_blkno = blkno; 236 } 237 } 238 } 239 240 /* 241 * handle the synchronous read 242 */ 243 if (bp) { 244 #if defined(CLUSTERDEBUG) 245 if (rcluster) 246 printf("S(%ld,%ld,%d) ", 247 (long)bp->b_lblkno, bp->b_bcount, seqcount); 248 #endif 249 if ((bp->b_flags & B_CLUSTER) == 0) 250 vfs_busy_pages(bp, 0); 251 bp->b_flags &= ~B_INVAL; 252 bp->b_ioflags &= ~BIO_ERROR; 253 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 254 BUF_KERNPROC(bp); 255 error = VOP_STRATEGY(vp, bp); 256 curproc->p_stats->p_ru.ru_inblock++; 257 } 258 259 /* 260 * and if we have read-aheads, do them too 261 */ 262 if (rbp) { 263 if (error) { 264 rbp->b_flags &= ~B_ASYNC; 265 brelse(rbp); 266 } else if (rbp->b_flags & B_CACHE) { 267 rbp->b_flags &= ~B_ASYNC; 268 bqrelse(rbp); 269 } else { 270 #if defined(CLUSTERDEBUG) 271 if (rcluster) { 272 if (bp) 273 printf("A+(%ld,%ld,%ld,%d) ", 274 (long)rbp->b_lblkno, rbp->b_bcount, 275 (long)(rbp->b_lblkno - origblkno), 276 seqcount); 277 else 278 printf("A(%ld,%ld,%ld,%d) ", 279 (long)rbp->b_lblkno, rbp->b_bcount, 280 (long)(rbp->b_lblkno - origblkno), 281 seqcount); 282 } 283 #endif 284 285 if ((rbp->b_flags & B_CLUSTER) == 0) 286 vfs_busy_pages(rbp, 0); 287 rbp->b_flags &= ~B_INVAL; 288 rbp->b_ioflags &= ~BIO_ERROR; 289 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 290 BUF_KERNPROC(rbp); 291 (void) VOP_STRATEGY(vp, rbp); 292 curproc->p_stats->p_ru.ru_inblock++; 293 } 294 } 295 if (reqbp) 296 return (bufwait(reqbp)); 297 else 298 return (error); 299 } 300 301 /* 302 * If blocks are contiguous on disk, use this to provide clustered 303 * read ahead. We will read as many blocks as possible sequentially 304 * and then parcel them up into logical blocks in the buffer hash table. 305 */ 306 static struct buf * 307 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 308 struct vnode *vp; 309 u_quad_t filesize; 310 daddr_t lbn; 311 daddr_t blkno; 312 long size; 313 int run; 314 struct buf *fbp; 315 { 316 struct buf *bp, *tbp; 317 daddr_t bn; 318 int i, inc, j; 319 320 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 321 ("cluster_rbuild: size %ld != filesize %ld\n", 322 size, vp->v_mount->mnt_stat.f_iosize)); 323 324 /* 325 * avoid a division 326 */ 327 while ((u_quad_t) size * (lbn + run) > filesize) { 328 --run; 329 } 330 331 if (fbp) { 332 tbp = fbp; 333 tbp->b_iocmd = BIO_READ; 334 } else { 335 tbp = getblk(vp, lbn, size, 0, 0); 336 if (tbp->b_flags & B_CACHE) 337 return tbp; 338 tbp->b_flags |= B_ASYNC | B_RAM; 339 tbp->b_iocmd = BIO_READ; 340 } 341 342 tbp->b_blkno = blkno; 343 if( (tbp->b_flags & B_MALLOC) || 344 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 345 return tbp; 346 347 bp = trypbuf(&cluster_pbuf_freecnt); 348 if (bp == 0) 349 return tbp; 350 351 bp->b_data = (char *)((vm_offset_t)bp->b_data | 352 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 353 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 354 bp->b_iocmd = BIO_READ; 355 bp->b_iodone = cluster_callback; 356 bp->b_blkno = blkno; 357 bp->b_lblkno = lbn; 358 bp->b_offset = tbp->b_offset; 359 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 360 pbgetvp(vp, bp); 361 362 TAILQ_INIT(&bp->b_cluster.cluster_head); 363 364 bp->b_bcount = 0; 365 bp->b_bufsize = 0; 366 bp->b_npages = 0; 367 368 inc = btodb(size); 369 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 370 if (i != 0) { 371 if ((bp->b_npages * PAGE_SIZE) + 372 round_page(size) > vp->v_mount->mnt_iosize_max) 373 break; 374 375 if ((tbp = incore(vp, lbn + i)) != NULL) { 376 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) 377 break; 378 BUF_UNLOCK(tbp); 379 380 for (j = 0; j < tbp->b_npages; j++) 381 if (tbp->b_pages[j]->valid) 382 break; 383 384 if (j != tbp->b_npages) 385 break; 386 387 if (tbp->b_bcount != size) 388 break; 389 } 390 391 tbp = getblk(vp, lbn + i, size, 0, 0); 392 393 if ((tbp->b_flags & B_CACHE) || 394 (tbp->b_flags & B_VMIO) == 0) { 395 bqrelse(tbp); 396 break; 397 } 398 399 for (j = 0;j < tbp->b_npages; j++) 400 if (tbp->b_pages[j]->valid) 401 break; 402 403 if (j != tbp->b_npages) { 404 bqrelse(tbp); 405 break; 406 } 407 408 if ((fbp && (i == 1)) || (i == (run - 1))) 409 tbp->b_flags |= B_RAM; 410 tbp->b_flags |= B_ASYNC; 411 tbp->b_iocmd = BIO_READ; 412 if (tbp->b_blkno == tbp->b_lblkno) { 413 tbp->b_blkno = bn; 414 } else if (tbp->b_blkno != bn) { 415 brelse(tbp); 416 break; 417 } 418 } 419 /* 420 * XXX fbp from caller may not be B_ASYNC, but we are going 421 * to biodone() it in cluster_callback() anyway 422 */ 423 BUF_KERNPROC(tbp); 424 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 425 tbp, b_cluster.cluster_entry); 426 for (j = 0; j < tbp->b_npages; j += 1) { 427 vm_page_t m; 428 m = tbp->b_pages[j]; 429 vm_page_io_start(m); 430 vm_object_pip_add(m->object, 1); 431 if ((bp->b_npages == 0) || 432 (bp->b_pages[bp->b_npages-1] != m)) { 433 bp->b_pages[bp->b_npages] = m; 434 bp->b_npages++; 435 } 436 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 437 tbp->b_pages[j] = bogus_page; 438 } 439 bp->b_bcount += tbp->b_bcount; 440 bp->b_bufsize += tbp->b_bufsize; 441 } 442 443 for(j=0;j<bp->b_npages;j++) { 444 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 445 VM_PAGE_BITS_ALL) 446 bp->b_pages[j] = bogus_page; 447 } 448 if (bp->b_bufsize > bp->b_kvasize) 449 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 450 bp->b_bufsize, bp->b_kvasize); 451 bp->b_kvasize = bp->b_bufsize; 452 453 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 454 (vm_page_t *)bp->b_pages, bp->b_npages); 455 return (bp); 456 } 457 458 /* 459 * Cleanup after a clustered read or write. 460 * This is complicated by the fact that any of the buffers might have 461 * extra memory (if there were no empty buffer headers at allocbuf time) 462 * that we will need to shift around. 463 */ 464 void 465 cluster_callback(bp) 466 struct buf *bp; 467 { 468 struct buf *nbp, *tbp; 469 int error = 0; 470 471 /* 472 * Must propogate errors to all the components. 473 */ 474 if (bp->b_ioflags & BIO_ERROR) 475 error = bp->b_error; 476 477 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 478 /* 479 * Move memory from the large cluster buffer into the component 480 * buffers and mark IO as done on these. 481 */ 482 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 483 tbp; tbp = nbp) { 484 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 485 if (error) { 486 tbp->b_ioflags |= BIO_ERROR; 487 tbp->b_error = error; 488 } else { 489 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 490 tbp->b_flags &= ~B_INVAL; 491 tbp->b_ioflags &= ~BIO_ERROR; 492 } 493 bufdone(tbp); 494 } 495 relpbuf(bp, &cluster_pbuf_freecnt); 496 } 497 498 /* 499 * cluster_wbuild_wb: 500 * 501 * Implement modified write build for cluster. 502 * 503 * write_behind = 0 write behind disabled 504 * write_behind = 1 write behind normal (default) 505 * write_behind = 2 write behind backed-off 506 */ 507 508 static __inline int 509 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 510 { 511 int r = 0; 512 513 switch(write_behind) { 514 case 2: 515 if (start_lbn < len) 516 break; 517 start_lbn -= len; 518 /* fall through */ 519 case 1: 520 r = cluster_wbuild(vp, size, start_lbn, len); 521 /* fall through */ 522 default: 523 /* fall through */ 524 break; 525 } 526 return(r); 527 } 528 529 /* 530 * Do clustered write for FFS. 531 * 532 * Three cases: 533 * 1. Write is not sequential (write asynchronously) 534 * Write is sequential: 535 * 2. beginning of cluster - begin cluster 536 * 3. middle of a cluster - add to cluster 537 * 4. end of a cluster - asynchronously write cluster 538 */ 539 void 540 cluster_write(bp, filesize, seqcount) 541 struct buf *bp; 542 u_quad_t filesize; 543 int seqcount; 544 { 545 struct vnode *vp; 546 daddr_t lbn; 547 int maxclen, cursize; 548 int lblocksize; 549 int async; 550 551 vp = bp->b_vp; 552 if (vp->v_type == VREG) { 553 async = vp->v_mount->mnt_flag & MNT_ASYNC; 554 lblocksize = vp->v_mount->mnt_stat.f_iosize; 555 } else { 556 async = 0; 557 lblocksize = bp->b_bufsize; 558 } 559 lbn = bp->b_lblkno; 560 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 561 562 /* Initialize vnode to beginning of file. */ 563 if (lbn == 0) 564 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 565 566 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 567 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 568 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 569 if (vp->v_clen != 0) { 570 /* 571 * Next block is not sequential. 572 * 573 * If we are not writing at end of file, the process 574 * seeked to another point in the file since its last 575 * write, or we have reached our maximum cluster size, 576 * then push the previous cluster. Otherwise try 577 * reallocating to make it sequential. 578 * 579 * Change to algorithm: only push previous cluster if 580 * it was sequential from the point of view of the 581 * seqcount heuristic, otherwise leave the buffer 582 * intact so we can potentially optimize the I/O 583 * later on in the buf_daemon or update daemon 584 * flush. 585 */ 586 cursize = vp->v_lastw - vp->v_cstart + 1; 587 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 588 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 589 if (!async && seqcount > 0) { 590 cluster_wbuild_wb(vp, lblocksize, 591 vp->v_cstart, cursize); 592 } 593 } else { 594 struct buf **bpp, **endbp; 595 struct cluster_save *buflist; 596 597 buflist = cluster_collectbufs(vp, bp); 598 endbp = &buflist->bs_children 599 [buflist->bs_nchildren - 1]; 600 if (VOP_REALLOCBLKS(vp, buflist)) { 601 /* 602 * Failed, push the previous cluster 603 * if *really* writing sequentially 604 * in the logical file (seqcount > 1), 605 * otherwise delay it in the hopes that 606 * the low level disk driver can 607 * optimize the write ordering. 608 */ 609 for (bpp = buflist->bs_children; 610 bpp < endbp; bpp++) 611 brelse(*bpp); 612 free(buflist, M_SEGMENT); 613 if (seqcount > 1) { 614 cluster_wbuild_wb(vp, 615 lblocksize, vp->v_cstart, 616 cursize); 617 } 618 } else { 619 /* 620 * Succeeded, keep building cluster. 621 */ 622 for (bpp = buflist->bs_children; 623 bpp <= endbp; bpp++) 624 bdwrite(*bpp); 625 free(buflist, M_SEGMENT); 626 vp->v_lastw = lbn; 627 vp->v_lasta = bp->b_blkno; 628 return; 629 } 630 } 631 } 632 /* 633 * Consider beginning a cluster. If at end of file, make 634 * cluster as large as possible, otherwise find size of 635 * existing cluster. 636 */ 637 if ((vp->v_type == VREG) && 638 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 639 (bp->b_blkno == bp->b_lblkno) && 640 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 641 bp->b_blkno == -1)) { 642 bawrite(bp); 643 vp->v_clen = 0; 644 vp->v_lasta = bp->b_blkno; 645 vp->v_cstart = lbn + 1; 646 vp->v_lastw = lbn; 647 return; 648 } 649 vp->v_clen = maxclen; 650 if (!async && maxclen == 0) { /* I/O not contiguous */ 651 vp->v_cstart = lbn + 1; 652 bawrite(bp); 653 } else { /* Wait for rest of cluster */ 654 vp->v_cstart = lbn; 655 bdwrite(bp); 656 } 657 } else if (lbn == vp->v_cstart + vp->v_clen) { 658 /* 659 * At end of cluster, write it out if seqcount tells us we 660 * are operating sequentially, otherwise let the buf or 661 * update daemon handle it. 662 */ 663 bdwrite(bp); 664 if (seqcount > 1) 665 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 666 vp->v_clen = 0; 667 vp->v_cstart = lbn + 1; 668 } else { 669 /* 670 * In the middle of a cluster, so just delay the I/O for now. 671 */ 672 bdwrite(bp); 673 } 674 vp->v_lastw = lbn; 675 vp->v_lasta = bp->b_blkno; 676 } 677 678 679 /* 680 * This is an awful lot like cluster_rbuild...wish they could be combined. 681 * The last lbn argument is the current block on which I/O is being 682 * performed. Check to see that it doesn't fall in the middle of 683 * the current block (if last_bp == NULL). 684 */ 685 int 686 cluster_wbuild(vp, size, start_lbn, len) 687 struct vnode *vp; 688 long size; 689 daddr_t start_lbn; 690 int len; 691 { 692 struct buf *bp, *tbp; 693 int i, j, s; 694 int totalwritten = 0; 695 int dbsize = btodb(size); 696 697 while (len > 0) { 698 s = splbio(); 699 if (((tbp = gbincore(vp, start_lbn)) == NULL) || 700 ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) || 701 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 702 ++start_lbn; 703 --len; 704 splx(s); 705 continue; 706 } 707 bremfree(tbp); 708 tbp->b_flags &= ~B_DONE; 709 splx(s); 710 711 /* 712 * Extra memory in the buffer, punt on this buffer. 713 * XXX we could handle this in most cases, but we would 714 * have to push the extra memory down to after our max 715 * possible cluster size and then potentially pull it back 716 * up if the cluster was terminated prematurely--too much 717 * hassle. 718 */ 719 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 720 (tbp->b_bcount != tbp->b_bufsize) || 721 (tbp->b_bcount != size) || 722 (len == 1) || 723 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 724 totalwritten += tbp->b_bufsize; 725 bawrite(tbp); 726 ++start_lbn; 727 --len; 728 continue; 729 } 730 731 /* 732 * We got a pbuf to make the cluster in. 733 * so initialise it. 734 */ 735 TAILQ_INIT(&bp->b_cluster.cluster_head); 736 bp->b_bcount = 0; 737 bp->b_bufsize = 0; 738 bp->b_npages = 0; 739 if (tbp->b_wcred != NOCRED) { 740 bp->b_wcred = tbp->b_wcred; 741 crhold(bp->b_wcred); 742 } 743 744 bp->b_blkno = tbp->b_blkno; 745 bp->b_lblkno = tbp->b_lblkno; 746 bp->b_offset = tbp->b_offset; 747 bp->b_data = (char *)((vm_offset_t)bp->b_data | 748 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 749 bp->b_flags |= B_CLUSTER | 750 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 751 bp->b_iodone = cluster_callback; 752 pbgetvp(vp, bp); 753 /* 754 * From this location in the file, scan forward to see 755 * if there are buffers with adjacent data that need to 756 * be written as well. 757 */ 758 for (i = 0; i < len; ++i, ++start_lbn) { 759 if (i != 0) { /* If not the first buffer */ 760 s = splbio(); 761 /* 762 * If the adjacent data is not even in core it 763 * can't need to be written. 764 */ 765 if ((tbp = gbincore(vp, start_lbn)) == NULL) { 766 splx(s); 767 break; 768 } 769 770 /* 771 * If it IS in core, but has different 772 * characteristics, don't cluster with it. 773 */ 774 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 775 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 776 != (B_DELWRI | B_CLUSTEROK | 777 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 778 tbp->b_wcred != bp->b_wcred || 779 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 780 splx(s); 781 break; 782 } 783 784 /* 785 * Check that the combined cluster 786 * would make sense with regard to pages 787 * and would not be too large 788 */ 789 if ((tbp->b_bcount != size) || 790 ((bp->b_blkno + (dbsize * i)) != 791 tbp->b_blkno) || 792 ((tbp->b_npages + bp->b_npages) > 793 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 794 BUF_UNLOCK(tbp); 795 splx(s); 796 break; 797 } 798 /* 799 * Ok, it's passed all the tests, 800 * so remove it from the free list 801 * and mark it busy. We will use it. 802 */ 803 bremfree(tbp); 804 tbp->b_flags &= ~B_DONE; 805 splx(s); 806 } /* end of code for non-first buffers only */ 807 /* check for latent dependencies to be handled */ 808 if ((LIST_FIRST(&tbp->b_dep)) != NULL && 809 bioops.io_start) 810 (*bioops.io_start)(tbp); 811 /* 812 * If the IO is via the VM then we do some 813 * special VM hackery. (yuck) 814 */ 815 if (tbp->b_flags & B_VMIO) { 816 vm_page_t m; 817 818 if (i != 0) { /* if not first buffer */ 819 for (j = 0; j < tbp->b_npages; j += 1) { 820 m = tbp->b_pages[j]; 821 if (m->flags & PG_BUSY) { 822 bqrelse(tbp); 823 goto finishcluster; 824 } 825 } 826 } 827 828 for (j = 0; j < tbp->b_npages; j += 1) { 829 m = tbp->b_pages[j]; 830 vm_page_io_start(m); 831 vm_object_pip_add(m->object, 1); 832 if ((bp->b_npages == 0) || 833 (bp->b_pages[bp->b_npages - 1] != m)) { 834 bp->b_pages[bp->b_npages] = m; 835 bp->b_npages++; 836 } 837 } 838 } 839 bp->b_bcount += size; 840 bp->b_bufsize += size; 841 842 s = splbio(); 843 bundirty(tbp); 844 tbp->b_flags &= ~B_DONE; 845 tbp->b_ioflags &= ~BIO_ERROR; 846 tbp->b_flags |= B_ASYNC; 847 tbp->b_iocmd = BIO_WRITE; 848 reassignbuf(tbp, tbp->b_vp); /* put on clean list */ 849 ++tbp->b_vp->v_numoutput; 850 splx(s); 851 BUF_KERNPROC(tbp); 852 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 853 tbp, b_cluster.cluster_entry); 854 } 855 finishcluster: 856 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 857 (vm_page_t *) bp->b_pages, bp->b_npages); 858 if (bp->b_bufsize > bp->b_kvasize) 859 panic( 860 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 861 bp->b_bufsize, bp->b_kvasize); 862 bp->b_kvasize = bp->b_bufsize; 863 totalwritten += bp->b_bufsize; 864 bp->b_dirtyoff = 0; 865 bp->b_dirtyend = bp->b_bufsize; 866 bawrite(bp); 867 868 len -= i; 869 } 870 return totalwritten; 871 } 872 873 /* 874 * Collect together all the buffers in a cluster. 875 * Plus add one additional buffer. 876 */ 877 static struct cluster_save * 878 cluster_collectbufs(vp, last_bp) 879 struct vnode *vp; 880 struct buf *last_bp; 881 { 882 struct cluster_save *buflist; 883 struct buf *bp; 884 daddr_t lbn; 885 int i, len; 886 887 len = vp->v_lastw - vp->v_cstart + 1; 888 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 889 M_SEGMENT, M_WAITOK); 890 buflist->bs_nchildren = 0; 891 buflist->bs_children = (struct buf **) (buflist + 1); 892 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 893 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 894 buflist->bs_children[i] = bp; 895 if (bp->b_blkno == bp->b_lblkno) 896 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, 897 NULL, NULL); 898 } 899 buflist->bs_children[i] = bp = last_bp; 900 if (bp->b_blkno == bp->b_lblkno) 901 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, 902 NULL, NULL); 903 buflist->bs_nchildren = i + 1; 904 return (buflist); 905 } 906