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: src/sys/kern/vfs_cluster.c,v 1.92.2.9 2001/11/18 07:10:59 dillon Exp $ 37 * $DragonFly: src/sys/kern/vfs_cluster.c,v 1.2 2003/06/17 04:28:42 dillon Exp $ 38 */ 39 40 #include "opt_debug_cluster.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/kernel.h> 45 #include <sys/proc.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 <sys/vmmeter.h> 52 #include <vm/vm.h> 53 #include <vm/vm_object.h> 54 #include <vm/vm_page.h> 55 #include <sys/sysctl.h> 56 57 #if defined(CLUSTERDEBUG) 58 #include <sys/sysctl.h> 59 static int rcluster= 0; 60 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, ""); 61 #endif 62 63 static MALLOC_DEFINE(M_SEGMENT, "cluster_save buffer", "cluster_save buffer"); 64 65 static struct cluster_save * 66 cluster_collectbufs __P((struct vnode *vp, struct buf *last_bp)); 67 static struct buf * 68 cluster_rbuild __P((struct vnode *vp, u_quad_t filesize, daddr_t lbn, 69 daddr_t blkno, long size, int run, struct buf *fbp)); 70 71 static int write_behind = 1; 72 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, ""); 73 74 extern vm_page_t bogus_page; 75 76 extern int cluster_pbuf_freecnt; 77 78 /* 79 * Maximum number of blocks for read-ahead. 80 */ 81 #define MAXRA 32 82 83 /* 84 * This replaces bread. 85 */ 86 int 87 cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp) 88 struct vnode *vp; 89 u_quad_t filesize; 90 daddr_t lblkno; 91 long size; 92 struct ucred *cred; 93 long totread; 94 int seqcount; 95 struct buf **bpp; 96 { 97 struct buf *bp, *rbp, *reqbp; 98 daddr_t blkno, origblkno; 99 int error, num_ra; 100 int i; 101 int maxra, racluster; 102 long origtotread; 103 104 error = 0; 105 106 /* 107 * Try to limit the amount of read-ahead by a few 108 * ad-hoc parameters. This needs work!!! 109 */ 110 racluster = vp->v_mount->mnt_iosize_max / size; 111 maxra = 2 * racluster + (totread / size); 112 if (maxra > MAXRA) 113 maxra = MAXRA; 114 if (maxra > nbuf/8) 115 maxra = nbuf/8; 116 117 /* 118 * get the requested block 119 */ 120 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0); 121 origblkno = lblkno; 122 origtotread = totread; 123 124 /* 125 * if it is in the cache, then check to see if the reads have been 126 * sequential. If they have, then try some read-ahead, otherwise 127 * back-off on prospective read-aheads. 128 */ 129 if (bp->b_flags & B_CACHE) { 130 if (!seqcount) { 131 return 0; 132 } else if ((bp->b_flags & B_RAM) == 0) { 133 return 0; 134 } else { 135 int s; 136 struct buf *tbp; 137 bp->b_flags &= ~B_RAM; 138 /* 139 * We do the spl here so that there is no window 140 * between the incore and the b_usecount increment 141 * below. We opt to keep the spl out of the loop 142 * for efficiency. 143 */ 144 s = splbio(); 145 for (i = 1; i < maxra; i++) { 146 147 if (!(tbp = incore(vp, lblkno+i))) { 148 break; 149 } 150 151 /* 152 * Set another read-ahead mark so we know 153 * to check again. 154 */ 155 if (((i % racluster) == (racluster - 1)) || 156 (i == (maxra - 1))) 157 tbp->b_flags |= B_RAM; 158 } 159 splx(s); 160 if (i >= maxra) { 161 return 0; 162 } 163 lblkno += i; 164 } 165 reqbp = bp = NULL; 166 } else { 167 off_t firstread = bp->b_offset; 168 169 KASSERT(bp->b_offset != NOOFFSET, 170 ("cluster_read: no buffer offset")); 171 if (firstread + totread > filesize) 172 totread = filesize - firstread; 173 if (totread > size) { 174 int nblks = 0; 175 int ncontigafter; 176 while (totread > 0) { 177 nblks++; 178 totread -= size; 179 } 180 if (nblks == 1) 181 goto single_block_read; 182 if (nblks > racluster) 183 nblks = racluster; 184 185 error = VOP_BMAP(vp, lblkno, NULL, 186 &blkno, &ncontigafter, NULL); 187 if (error) 188 goto single_block_read; 189 if (blkno == -1) 190 goto single_block_read; 191 if (ncontigafter == 0) 192 goto single_block_read; 193 if (ncontigafter + 1 < nblks) 194 nblks = ncontigafter + 1; 195 196 bp = cluster_rbuild(vp, filesize, lblkno, 197 blkno, size, nblks, bp); 198 lblkno += (bp->b_bufsize / size); 199 } else { 200 single_block_read: 201 /* 202 * if it isn't in the cache, then get a chunk from 203 * disk if sequential, otherwise just get the block. 204 */ 205 bp->b_flags |= B_READ | B_RAM; 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_READ | B_ASYNC | B_RAM; 234 rbp->b_blkno = blkno; 235 } 236 } 237 } 238 239 /* 240 * handle the synchronous read 241 */ 242 if (bp) { 243 #if defined(CLUSTERDEBUG) 244 if (rcluster) 245 printf("S(%ld,%ld,%d) ", 246 (long)bp->b_lblkno, bp->b_bcount, seqcount); 247 #endif 248 if ((bp->b_flags & B_CLUSTER) == 0) { 249 vfs_busy_pages(bp, 0); 250 } 251 bp->b_flags &= ~(B_ERROR|B_INVAL); 252 if (bp->b_flags & (B_ASYNC|B_CALL)) 253 BUF_KERNPROC(bp); 254 error = VOP_STRATEGY(vp, bp); 255 curproc->p_stats->p_ru.ru_inblock++; 256 } 257 258 /* 259 * and if we have read-aheads, do them too 260 */ 261 if (rbp) { 262 if (error) { 263 rbp->b_flags &= ~(B_ASYNC | B_READ); 264 brelse(rbp); 265 } else if (rbp->b_flags & B_CACHE) { 266 rbp->b_flags &= ~(B_ASYNC | B_READ); 267 bqrelse(rbp); 268 } else { 269 #if defined(CLUSTERDEBUG) 270 if (rcluster) { 271 if (bp) 272 printf("A+(%ld,%ld,%ld,%d) ", 273 (long)rbp->b_lblkno, rbp->b_bcount, 274 (long)(rbp->b_lblkno - origblkno), 275 seqcount); 276 else 277 printf("A(%ld,%ld,%ld,%d) ", 278 (long)rbp->b_lblkno, rbp->b_bcount, 279 (long)(rbp->b_lblkno - origblkno), 280 seqcount); 281 } 282 #endif 283 284 if ((rbp->b_flags & B_CLUSTER) == 0) { 285 vfs_busy_pages(rbp, 0); 286 } 287 rbp->b_flags &= ~(B_ERROR|B_INVAL); 288 if (rbp->b_flags & (B_ASYNC|B_CALL)) 289 BUF_KERNPROC(rbp); 290 (void) VOP_STRATEGY(vp, rbp); 291 curproc->p_stats->p_ru.ru_inblock++; 292 } 293 } 294 if (reqbp) 295 return (biowait(reqbp)); 296 else 297 return (error); 298 } 299 300 /* 301 * If blocks are contiguous on disk, use this to provide clustered 302 * read ahead. We will read as many blocks as possible sequentially 303 * and then parcel them up into logical blocks in the buffer hash table. 304 */ 305 static struct buf * 306 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 307 struct vnode *vp; 308 u_quad_t filesize; 309 daddr_t lbn; 310 daddr_t blkno; 311 long size; 312 int run; 313 struct buf *fbp; 314 { 315 struct buf *bp, *tbp; 316 daddr_t bn; 317 int i, inc, j; 318 319 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 320 ("cluster_rbuild: size %ld != filesize %ld\n", 321 size, vp->v_mount->mnt_stat.f_iosize)); 322 323 /* 324 * avoid a division 325 */ 326 while ((u_quad_t) size * (lbn + run) > filesize) { 327 --run; 328 } 329 330 if (fbp) { 331 tbp = fbp; 332 tbp->b_flags |= B_READ; 333 } else { 334 tbp = getblk(vp, lbn, size, 0, 0); 335 if (tbp->b_flags & B_CACHE) 336 return tbp; 337 tbp->b_flags |= B_ASYNC | B_READ | B_RAM; 338 } 339 340 tbp->b_blkno = blkno; 341 if( (tbp->b_flags & B_MALLOC) || 342 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 343 return tbp; 344 345 bp = trypbuf(&cluster_pbuf_freecnt); 346 if (bp == 0) 347 return tbp; 348 349 /* 350 * We are synthesizing a buffer out of vm_page_t's, but 351 * if the block size is not page aligned then the starting 352 * address may not be either. Inherit the b_data offset 353 * from the original buffer. 354 */ 355 bp->b_data = (char *)((vm_offset_t)bp->b_data | 356 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 357 bp->b_flags = B_ASYNC | B_READ | B_CALL | B_CLUSTER | B_VMIO; 358 bp->b_iodone = cluster_callback; 359 bp->b_blkno = blkno; 360 bp->b_lblkno = lbn; 361 bp->b_offset = tbp->b_offset; 362 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 363 pbgetvp(vp, bp); 364 365 TAILQ_INIT(&bp->b_cluster.cluster_head); 366 367 bp->b_bcount = 0; 368 bp->b_bufsize = 0; 369 bp->b_npages = 0; 370 371 inc = btodb(size); 372 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 373 if (i != 0) { 374 if ((bp->b_npages * PAGE_SIZE) + 375 round_page(size) > vp->v_mount->mnt_iosize_max) { 376 break; 377 } 378 379 /* 380 * Shortcut some checks and try to avoid buffers that 381 * would block in the lock. The same checks have to 382 * be made again after we officially get the buffer. 383 */ 384 if ((tbp = incore(vp, lbn + i)) != NULL) { 385 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) 386 break; 387 BUF_UNLOCK(tbp); 388 389 for (j = 0; j < tbp->b_npages; j++) { 390 if (tbp->b_pages[j]->valid) 391 break; 392 } 393 394 if (j != tbp->b_npages) 395 break; 396 397 if (tbp->b_bcount != size) 398 break; 399 } 400 401 tbp = getblk(vp, lbn + i, size, 0, 0); 402 403 /* 404 * Stop scanning if the buffer is fuly valid 405 * (marked B_CACHE), or locked (may be doing a 406 * background write), or if the buffer is not 407 * VMIO backed. The clustering code can only deal 408 * with VMIO-backed buffers. 409 */ 410 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || 411 (tbp->b_flags & B_VMIO) == 0) { 412 bqrelse(tbp); 413 break; 414 } 415 416 /* 417 * The buffer must be completely invalid in order to 418 * take part in the cluster. If it is partially valid 419 * then we stop. 420 */ 421 for (j = 0;j < tbp->b_npages; j++) { 422 if (tbp->b_pages[j]->valid) 423 break; 424 } 425 if (j != tbp->b_npages) { 426 bqrelse(tbp); 427 break; 428 } 429 430 /* 431 * Set a read-ahead mark as appropriate 432 */ 433 if ((fbp && (i == 1)) || (i == (run - 1))) 434 tbp->b_flags |= B_RAM; 435 436 /* 437 * Set the buffer up for an async read (XXX should 438 * we do this only if we do not wind up brelse()ing?). 439 * Set the block number if it isn't set, otherwise 440 * if it is make sure it matches the block number we 441 * expect. 442 */ 443 tbp->b_flags |= B_READ | B_ASYNC; 444 if (tbp->b_blkno == tbp->b_lblkno) { 445 tbp->b_blkno = bn; 446 } else if (tbp->b_blkno != bn) { 447 brelse(tbp); 448 break; 449 } 450 } 451 /* 452 * XXX fbp from caller may not be B_ASYNC, but we are going 453 * to biodone() it in cluster_callback() anyway 454 */ 455 BUF_KERNPROC(tbp); 456 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 457 tbp, b_cluster.cluster_entry); 458 for (j = 0; j < tbp->b_npages; j += 1) { 459 vm_page_t m; 460 m = tbp->b_pages[j]; 461 vm_page_io_start(m); 462 vm_object_pip_add(m->object, 1); 463 if ((bp->b_npages == 0) || 464 (bp->b_pages[bp->b_npages-1] != m)) { 465 bp->b_pages[bp->b_npages] = m; 466 bp->b_npages++; 467 } 468 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 469 tbp->b_pages[j] = bogus_page; 470 } 471 /* 472 * XXX shouldn't this be += size for both, like in 473 * cluster_wbuild()? 474 * 475 * Don't inherit tbp->b_bufsize as it may be larger due to 476 * a non-page-aligned size. Instead just aggregate using 477 * 'size'. 478 */ 479 if (tbp->b_bcount != size) 480 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 481 if (tbp->b_bufsize != size) 482 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 483 bp->b_bcount += size; 484 bp->b_bufsize += size; 485 } 486 487 /* 488 * Fully valid pages in the cluster are already good and do not need 489 * to be re-read from disk. Replace the page with bogus_page 490 */ 491 for (j = 0; j < bp->b_npages; j++) { 492 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 493 VM_PAGE_BITS_ALL) { 494 bp->b_pages[j] = bogus_page; 495 } 496 } 497 if (bp->b_bufsize > bp->b_kvasize) 498 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 499 bp->b_bufsize, bp->b_kvasize); 500 bp->b_kvasize = bp->b_bufsize; 501 502 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 503 (vm_page_t *)bp->b_pages, bp->b_npages); 504 return (bp); 505 } 506 507 /* 508 * Cleanup after a clustered read or write. 509 * This is complicated by the fact that any of the buffers might have 510 * extra memory (if there were no empty buffer headers at allocbuf time) 511 * that we will need to shift around. 512 */ 513 void 514 cluster_callback(bp) 515 struct buf *bp; 516 { 517 struct buf *nbp, *tbp; 518 int error = 0; 519 520 /* 521 * Must propogate errors to all the components. 522 */ 523 if (bp->b_flags & B_ERROR) 524 error = bp->b_error; 525 526 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 527 /* 528 * Move memory from the large cluster buffer into the component 529 * buffers and mark IO as done on these. 530 */ 531 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 532 tbp; tbp = nbp) { 533 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 534 if (error) { 535 tbp->b_flags |= B_ERROR; 536 tbp->b_error = error; 537 } else { 538 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 539 tbp->b_flags &= ~(B_ERROR|B_INVAL); 540 /* 541 * XXX the bdwrite()/bqrelse() issued during 542 * cluster building clears B_RELBUF (see bqrelse() 543 * comment). If direct I/O was specified, we have 544 * to restore it here to allow the buffer and VM 545 * to be freed. 546 */ 547 if (tbp->b_flags & B_DIRECT) 548 tbp->b_flags |= B_RELBUF; 549 } 550 biodone(tbp); 551 } 552 relpbuf(bp, &cluster_pbuf_freecnt); 553 } 554 555 /* 556 * cluster_wbuild_wb: 557 * 558 * Implement modified write build for cluster. 559 * 560 * write_behind = 0 write behind disabled 561 * write_behind = 1 write behind normal (default) 562 * write_behind = 2 write behind backed-off 563 */ 564 565 static __inline int 566 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 567 { 568 int r = 0; 569 570 switch(write_behind) { 571 case 2: 572 if (start_lbn < len) 573 break; 574 start_lbn -= len; 575 /* fall through */ 576 case 1: 577 r = cluster_wbuild(vp, size, start_lbn, len); 578 /* fall through */ 579 default: 580 /* fall through */ 581 break; 582 } 583 return(r); 584 } 585 586 /* 587 * Do clustered write for FFS. 588 * 589 * Three cases: 590 * 1. Write is not sequential (write asynchronously) 591 * Write is sequential: 592 * 2. beginning of cluster - begin cluster 593 * 3. middle of a cluster - add to cluster 594 * 4. end of a cluster - asynchronously write cluster 595 */ 596 void 597 cluster_write(bp, filesize, seqcount) 598 struct buf *bp; 599 u_quad_t filesize; 600 int seqcount; 601 { 602 struct vnode *vp; 603 daddr_t lbn; 604 int maxclen, cursize; 605 int lblocksize; 606 int async; 607 608 vp = bp->b_vp; 609 if (vp->v_type == VREG) { 610 async = vp->v_mount->mnt_flag & MNT_ASYNC; 611 lblocksize = vp->v_mount->mnt_stat.f_iosize; 612 } else { 613 async = 0; 614 lblocksize = bp->b_bufsize; 615 } 616 lbn = bp->b_lblkno; 617 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 618 619 /* Initialize vnode to beginning of file. */ 620 if (lbn == 0) 621 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 622 623 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 624 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 625 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 626 if (vp->v_clen != 0) { 627 /* 628 * Next block is not sequential. 629 * 630 * If we are not writing at end of file, the process 631 * seeked to another point in the file since its last 632 * write, or we have reached our maximum cluster size, 633 * then push the previous cluster. Otherwise try 634 * reallocating to make it sequential. 635 * 636 * Change to algorithm: only push previous cluster if 637 * it was sequential from the point of view of the 638 * seqcount heuristic, otherwise leave the buffer 639 * intact so we can potentially optimize the I/O 640 * later on in the buf_daemon or update daemon 641 * flush. 642 */ 643 cursize = vp->v_lastw - vp->v_cstart + 1; 644 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 645 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 646 if (!async && seqcount > 0) { 647 cluster_wbuild_wb(vp, lblocksize, 648 vp->v_cstart, cursize); 649 } 650 } else { 651 struct buf **bpp, **endbp; 652 struct cluster_save *buflist; 653 654 buflist = cluster_collectbufs(vp, bp); 655 endbp = &buflist->bs_children 656 [buflist->bs_nchildren - 1]; 657 if (VOP_REALLOCBLKS(vp, buflist)) { 658 /* 659 * Failed, push the previous cluster 660 * if *really* writing sequentially 661 * in the logical file (seqcount > 1), 662 * otherwise delay it in the hopes that 663 * the low level disk driver can 664 * optimize the write ordering. 665 */ 666 for (bpp = buflist->bs_children; 667 bpp < endbp; bpp++) 668 brelse(*bpp); 669 free(buflist, M_SEGMENT); 670 if (seqcount > 1) { 671 cluster_wbuild_wb(vp, 672 lblocksize, vp->v_cstart, 673 cursize); 674 } 675 } else { 676 /* 677 * Succeeded, keep building cluster. 678 */ 679 for (bpp = buflist->bs_children; 680 bpp <= endbp; bpp++) 681 bdwrite(*bpp); 682 free(buflist, M_SEGMENT); 683 vp->v_lastw = lbn; 684 vp->v_lasta = bp->b_blkno; 685 return; 686 } 687 } 688 } 689 /* 690 * Consider beginning a cluster. If at end of file, make 691 * cluster as large as possible, otherwise find size of 692 * existing cluster. 693 */ 694 if ((vp->v_type == VREG) && 695 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 696 (bp->b_blkno == bp->b_lblkno) && 697 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 698 bp->b_blkno == -1)) { 699 bawrite(bp); 700 vp->v_clen = 0; 701 vp->v_lasta = bp->b_blkno; 702 vp->v_cstart = lbn + 1; 703 vp->v_lastw = lbn; 704 return; 705 } 706 vp->v_clen = maxclen; 707 if (!async && maxclen == 0) { /* I/O not contiguous */ 708 vp->v_cstart = lbn + 1; 709 bawrite(bp); 710 } else { /* Wait for rest of cluster */ 711 vp->v_cstart = lbn; 712 bdwrite(bp); 713 } 714 } else if (lbn == vp->v_cstart + vp->v_clen) { 715 /* 716 * At end of cluster, write it out if seqcount tells us we 717 * are operating sequentially, otherwise let the buf or 718 * update daemon handle it. 719 */ 720 bdwrite(bp); 721 if (seqcount > 1) 722 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 723 vp->v_clen = 0; 724 vp->v_cstart = lbn + 1; 725 } else if (vm_page_count_severe()) { 726 /* 727 * We are low on memory, get it going NOW 728 */ 729 bawrite(bp); 730 } else { 731 /* 732 * In the middle of a cluster, so just delay the I/O for now. 733 */ 734 bdwrite(bp); 735 } 736 vp->v_lastw = lbn; 737 vp->v_lasta = bp->b_blkno; 738 } 739 740 741 /* 742 * This is an awful lot like cluster_rbuild...wish they could be combined. 743 * The last lbn argument is the current block on which I/O is being 744 * performed. Check to see that it doesn't fall in the middle of 745 * the current block (if last_bp == NULL). 746 */ 747 int 748 cluster_wbuild(vp, size, start_lbn, len) 749 struct vnode *vp; 750 long size; 751 daddr_t start_lbn; 752 int len; 753 { 754 struct buf *bp, *tbp; 755 int i, j, s; 756 int totalwritten = 0; 757 int dbsize = btodb(size); 758 759 while (len > 0) { 760 s = splbio(); 761 /* 762 * If the buffer is not delayed-write (i.e. dirty), or it 763 * is delayed-write but either locked or inval, it cannot 764 * partake in the clustered write. 765 */ 766 if (((tbp = gbincore(vp, start_lbn)) == NULL) || 767 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 768 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 769 ++start_lbn; 770 --len; 771 splx(s); 772 continue; 773 } 774 bremfree(tbp); 775 tbp->b_flags &= ~B_DONE; 776 splx(s); 777 778 /* 779 * Extra memory in the buffer, punt on this buffer. 780 * XXX we could handle this in most cases, but we would 781 * have to push the extra memory down to after our max 782 * possible cluster size and then potentially pull it back 783 * up if the cluster was terminated prematurely--too much 784 * hassle. 785 */ 786 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 787 (tbp->b_bcount != tbp->b_bufsize) || 788 (tbp->b_bcount != size) || 789 (len == 1) || 790 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 791 totalwritten += tbp->b_bufsize; 792 bawrite(tbp); 793 ++start_lbn; 794 --len; 795 continue; 796 } 797 798 /* 799 * We got a pbuf to make the cluster in. 800 * so initialise it. 801 */ 802 TAILQ_INIT(&bp->b_cluster.cluster_head); 803 bp->b_bcount = 0; 804 bp->b_bufsize = 0; 805 bp->b_npages = 0; 806 if (tbp->b_wcred != NOCRED) { 807 bp->b_wcred = tbp->b_wcred; 808 crhold(bp->b_wcred); 809 } 810 811 bp->b_blkno = tbp->b_blkno; 812 bp->b_lblkno = tbp->b_lblkno; 813 bp->b_offset = tbp->b_offset; 814 815 /* 816 * We are synthesizing a buffer out of vm_page_t's, but 817 * if the block size is not page aligned then the starting 818 * address may not be either. Inherit the b_data offset 819 * from the original buffer. 820 */ 821 bp->b_data = (char *)((vm_offset_t)bp->b_data | 822 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 823 bp->b_flags |= B_CALL | B_CLUSTER | 824 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN)); 825 bp->b_iodone = cluster_callback; 826 pbgetvp(vp, bp); 827 /* 828 * From this location in the file, scan forward to see 829 * if there are buffers with adjacent data that need to 830 * be written as well. 831 */ 832 for (i = 0; i < len; ++i, ++start_lbn) { 833 if (i != 0) { /* If not the first buffer */ 834 s = splbio(); 835 /* 836 * If the adjacent data is not even in core it 837 * can't need to be written. 838 */ 839 if ((tbp = gbincore(vp, start_lbn)) == NULL) { 840 splx(s); 841 break; 842 } 843 844 /* 845 * If it IS in core, but has different 846 * characteristics, or is locked (which 847 * means it could be undergoing a background 848 * I/O or be in a weird state), then don't 849 * cluster with it. 850 */ 851 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 852 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 853 != (B_DELWRI | B_CLUSTEROK | 854 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 855 (tbp->b_flags & B_LOCKED) || 856 tbp->b_wcred != bp->b_wcred || 857 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 858 splx(s); 859 break; 860 } 861 862 /* 863 * Check that the combined cluster 864 * would make sense with regard to pages 865 * and would not be too large 866 */ 867 if ((tbp->b_bcount != size) || 868 ((bp->b_blkno + (dbsize * i)) != 869 tbp->b_blkno) || 870 ((tbp->b_npages + bp->b_npages) > 871 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 872 BUF_UNLOCK(tbp); 873 splx(s); 874 break; 875 } 876 /* 877 * Ok, it's passed all the tests, 878 * so remove it from the free list 879 * and mark it busy. We will use it. 880 */ 881 bremfree(tbp); 882 tbp->b_flags &= ~B_DONE; 883 splx(s); 884 } /* end of code for non-first buffers only */ 885 /* check for latent dependencies to be handled */ 886 if ((LIST_FIRST(&tbp->b_dep)) != NULL && 887 bioops.io_start) 888 (*bioops.io_start)(tbp); 889 /* 890 * If the IO is via the VM then we do some 891 * special VM hackery (yuck). Since the buffer's 892 * block size may not be page-aligned it is possible 893 * for a page to be shared between two buffers. We 894 * have to get rid of the duplication when building 895 * the cluster. 896 */ 897 if (tbp->b_flags & B_VMIO) { 898 vm_page_t m; 899 900 if (i != 0) { /* if not first buffer */ 901 for (j = 0; j < tbp->b_npages; j += 1) { 902 m = tbp->b_pages[j]; 903 if (m->flags & PG_BUSY) { 904 bqrelse(tbp); 905 goto finishcluster; 906 } 907 } 908 } 909 910 for (j = 0; j < tbp->b_npages; j += 1) { 911 m = tbp->b_pages[j]; 912 vm_page_io_start(m); 913 vm_object_pip_add(m->object, 1); 914 if ((bp->b_npages == 0) || 915 (bp->b_pages[bp->b_npages - 1] != m)) { 916 bp->b_pages[bp->b_npages] = m; 917 bp->b_npages++; 918 } 919 } 920 } 921 bp->b_bcount += size; 922 bp->b_bufsize += size; 923 924 s = splbio(); 925 bundirty(tbp); 926 tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR); 927 tbp->b_flags |= B_ASYNC; 928 reassignbuf(tbp, tbp->b_vp); /* put on clean list */ 929 ++tbp->b_vp->v_numoutput; 930 splx(s); 931 BUF_KERNPROC(tbp); 932 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 933 tbp, b_cluster.cluster_entry); 934 } 935 finishcluster: 936 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 937 (vm_page_t *) bp->b_pages, bp->b_npages); 938 if (bp->b_bufsize > bp->b_kvasize) 939 panic( 940 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 941 bp->b_bufsize, bp->b_kvasize); 942 bp->b_kvasize = bp->b_bufsize; 943 totalwritten += bp->b_bufsize; 944 bp->b_dirtyoff = 0; 945 bp->b_dirtyend = bp->b_bufsize; 946 bawrite(bp); 947 948 len -= i; 949 } 950 return totalwritten; 951 } 952 953 /* 954 * Collect together all the buffers in a cluster. 955 * Plus add one additional buffer. 956 */ 957 static struct cluster_save * 958 cluster_collectbufs(vp, last_bp) 959 struct vnode *vp; 960 struct buf *last_bp; 961 { 962 struct cluster_save *buflist; 963 struct buf *bp; 964 daddr_t lbn; 965 int i, len; 966 967 len = vp->v_lastw - vp->v_cstart + 1; 968 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 969 M_SEGMENT, M_WAITOK); 970 buflist->bs_nchildren = 0; 971 buflist->bs_children = (struct buf **) (buflist + 1); 972 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 973 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 974 buflist->bs_children[i] = bp; 975 if (bp->b_blkno == bp->b_lblkno) 976 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, 977 NULL, NULL); 978 } 979 buflist->bs_children[i] = bp = last_bp; 980 if (bp->b_blkno == bp->b_lblkno) 981 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, 982 NULL, NULL); 983 buflist->bs_nchildren = i + 1; 984 return (buflist); 985 } 986