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 <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_RAM; 206 bp->b_iocmd = BIO_READ; 207 lblkno += 1; 208 } 209 } 210 211 /* 212 * if we have been doing sequential I/O, then do some read-ahead 213 */ 214 rbp = NULL; 215 if (seqcount && (lblkno < (origblkno + seqcount))) { 216 /* 217 * we now build the read-ahead buffer if it is desirable. 218 */ 219 if (((u_quad_t)(lblkno + 1) * size) <= filesize && 220 !(error = VOP_BMAP(vp, lblkno, NULL, &blkno, &num_ra, NULL)) && 221 blkno != -1) { 222 int nblksread; 223 int ntoread = num_ra + 1; 224 nblksread = (origtotread + size - 1) / size; 225 if (seqcount < nblksread) 226 seqcount = nblksread; 227 if (seqcount < ntoread) 228 ntoread = seqcount; 229 if (num_ra) { 230 rbp = cluster_rbuild(vp, filesize, lblkno, 231 blkno, size, ntoread, NULL); 232 } else { 233 rbp = getblk(vp, lblkno, size, 0, 0); 234 rbp->b_flags |= B_ASYNC | B_RAM; 235 rbp->b_iocmd = BIO_READ; 236 rbp->b_blkno = blkno; 237 } 238 } 239 } 240 241 /* 242 * handle the synchronous read 243 */ 244 if (bp) { 245 #if defined(CLUSTERDEBUG) 246 if (rcluster) 247 printf("S(%ld,%ld,%d) ", 248 (long)bp->b_lblkno, bp->b_bcount, seqcount); 249 #endif 250 if ((bp->b_flags & B_CLUSTER) == 0) { 251 vfs_busy_pages(bp, 0); 252 } else { 253 bp->b_runningbufspace = bp->b_bufsize; 254 runningbufspace += bp->b_runningbufspace; 255 } 256 bp->b_flags &= ~B_INVAL; 257 bp->b_ioflags &= ~BIO_ERROR; 258 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 259 BUF_KERNPROC(bp); 260 error = VOP_STRATEGY(vp, bp); 261 curproc->p_stats->p_ru.ru_inblock++; 262 } 263 264 /* 265 * and if we have read-aheads, do them too 266 */ 267 if (rbp) { 268 if (error) { 269 rbp->b_flags &= ~B_ASYNC; 270 brelse(rbp); 271 } else if (rbp->b_flags & B_CACHE) { 272 rbp->b_flags &= ~B_ASYNC; 273 bqrelse(rbp); 274 } else { 275 #if defined(CLUSTERDEBUG) 276 if (rcluster) { 277 if (bp) 278 printf("A+(%ld,%ld,%ld,%d) ", 279 (long)rbp->b_lblkno, rbp->b_bcount, 280 (long)(rbp->b_lblkno - origblkno), 281 seqcount); 282 else 283 printf("A(%ld,%ld,%ld,%d) ", 284 (long)rbp->b_lblkno, rbp->b_bcount, 285 (long)(rbp->b_lblkno - origblkno), 286 seqcount); 287 } 288 #endif 289 290 if ((rbp->b_flags & B_CLUSTER) == 0) { 291 vfs_busy_pages(rbp, 0); 292 } else { 293 rbp->b_runningbufspace = rbp->b_bufsize; 294 runningbufspace += rbp->b_runningbufspace; 295 } 296 rbp->b_flags &= ~B_INVAL; 297 rbp->b_ioflags &= ~BIO_ERROR; 298 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 299 BUF_KERNPROC(rbp); 300 (void) VOP_STRATEGY(vp, rbp); 301 curproc->p_stats->p_ru.ru_inblock++; 302 } 303 } 304 if (reqbp) 305 return (bufwait(reqbp)); 306 else 307 return (error); 308 } 309 310 /* 311 * If blocks are contiguous on disk, use this to provide clustered 312 * read ahead. We will read as many blocks as possible sequentially 313 * and then parcel them up into logical blocks in the buffer hash table. 314 */ 315 static struct buf * 316 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 317 struct vnode *vp; 318 u_quad_t filesize; 319 daddr_t lbn; 320 daddr_t blkno; 321 long size; 322 int run; 323 struct buf *fbp; 324 { 325 struct buf *bp, *tbp; 326 daddr_t bn; 327 int i, inc, j; 328 329 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 330 ("cluster_rbuild: size %ld != filesize %ld\n", 331 size, vp->v_mount->mnt_stat.f_iosize)); 332 333 /* 334 * avoid a division 335 */ 336 while ((u_quad_t) size * (lbn + run) > filesize) { 337 --run; 338 } 339 340 if (fbp) { 341 tbp = fbp; 342 tbp->b_iocmd = BIO_READ; 343 } else { 344 tbp = getblk(vp, lbn, size, 0, 0); 345 if (tbp->b_flags & B_CACHE) 346 return tbp; 347 tbp->b_flags |= B_ASYNC | B_RAM; 348 tbp->b_iocmd = BIO_READ; 349 } 350 351 tbp->b_blkno = blkno; 352 if( (tbp->b_flags & B_MALLOC) || 353 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 354 return tbp; 355 356 bp = trypbuf(&cluster_pbuf_freecnt); 357 if (bp == 0) 358 return tbp; 359 360 bp->b_data = (char *)((vm_offset_t)bp->b_data | 361 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 362 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 363 bp->b_iocmd = BIO_READ; 364 bp->b_iodone = cluster_callback; 365 bp->b_blkno = blkno; 366 bp->b_lblkno = lbn; 367 bp->b_offset = tbp->b_offset; 368 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 369 pbgetvp(vp, bp); 370 371 TAILQ_INIT(&bp->b_cluster.cluster_head); 372 373 bp->b_bcount = 0; 374 bp->b_bufsize = 0; 375 bp->b_npages = 0; 376 377 inc = btodb(size); 378 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 379 if (i != 0) { 380 if ((bp->b_npages * PAGE_SIZE) + 381 round_page(size) > vp->v_mount->mnt_iosize_max) 382 break; 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 if (j != tbp->b_npages) 394 break; 395 396 if (tbp->b_bcount != size) 397 break; 398 } 399 400 tbp = getblk(vp, lbn + i, size, 0, 0); 401 402 /* 403 * If the buffer is already fully valid or locked 404 * (which could also mean that a background write is 405 * in progress), or the buffer is not backed by VMIO, 406 * stop. 407 */ 408 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || 409 (tbp->b_flags & B_VMIO) == 0) { 410 bqrelse(tbp); 411 break; 412 } 413 414 for (j = 0;j < tbp->b_npages; j++) { 415 if (tbp->b_pages[j]->valid) 416 break; 417 } 418 419 if (j != tbp->b_npages) { 420 bqrelse(tbp); 421 break; 422 } 423 424 if ((fbp && (i == 1)) || (i == (run - 1))) 425 tbp->b_flags |= B_RAM; 426 tbp->b_flags |= B_ASYNC; 427 tbp->b_iocmd = BIO_READ; 428 if (tbp->b_blkno == tbp->b_lblkno) { 429 tbp->b_blkno = bn; 430 } else if (tbp->b_blkno != bn) { 431 brelse(tbp); 432 break; 433 } 434 } 435 /* 436 * XXX fbp from caller may not be B_ASYNC, but we are going 437 * to biodone() it in cluster_callback() anyway 438 */ 439 BUF_KERNPROC(tbp); 440 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 441 tbp, b_cluster.cluster_entry); 442 for (j = 0; j < tbp->b_npages; j += 1) { 443 vm_page_t m; 444 m = tbp->b_pages[j]; 445 vm_page_io_start(m); 446 vm_object_pip_add(m->object, 1); 447 if ((bp->b_npages == 0) || 448 (bp->b_pages[bp->b_npages-1] != m)) { 449 bp->b_pages[bp->b_npages] = m; 450 bp->b_npages++; 451 } 452 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 453 tbp->b_pages[j] = bogus_page; 454 } 455 bp->b_bcount += tbp->b_bcount; 456 bp->b_bufsize += tbp->b_bufsize; 457 } 458 459 for(j=0;j<bp->b_npages;j++) { 460 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 461 VM_PAGE_BITS_ALL) 462 bp->b_pages[j] = bogus_page; 463 } 464 if (bp->b_bufsize > bp->b_kvasize) 465 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 466 bp->b_bufsize, bp->b_kvasize); 467 bp->b_kvasize = bp->b_bufsize; 468 469 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 470 (vm_page_t *)bp->b_pages, bp->b_npages); 471 return (bp); 472 } 473 474 /* 475 * Cleanup after a clustered read or write. 476 * This is complicated by the fact that any of the buffers might have 477 * extra memory (if there were no empty buffer headers at allocbuf time) 478 * that we will need to shift around. 479 */ 480 void 481 cluster_callback(bp) 482 struct buf *bp; 483 { 484 struct buf *nbp, *tbp; 485 int error = 0; 486 487 /* 488 * Must propogate errors to all the components. 489 */ 490 if (bp->b_ioflags & BIO_ERROR) 491 error = bp->b_error; 492 493 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 494 /* 495 * Move memory from the large cluster buffer into the component 496 * buffers and mark IO as done on these. 497 */ 498 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 499 tbp; tbp = nbp) { 500 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 501 if (error) { 502 tbp->b_ioflags |= BIO_ERROR; 503 tbp->b_error = error; 504 } else { 505 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 506 tbp->b_flags &= ~B_INVAL; 507 tbp->b_ioflags &= ~BIO_ERROR; 508 } 509 bufdone(tbp); 510 } 511 relpbuf(bp, &cluster_pbuf_freecnt); 512 } 513 514 /* 515 * cluster_wbuild_wb: 516 * 517 * Implement modified write build for cluster. 518 * 519 * write_behind = 0 write behind disabled 520 * write_behind = 1 write behind normal (default) 521 * write_behind = 2 write behind backed-off 522 */ 523 524 static __inline int 525 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 526 { 527 int r = 0; 528 529 switch(write_behind) { 530 case 2: 531 if (start_lbn < len) 532 break; 533 start_lbn -= len; 534 /* fall through */ 535 case 1: 536 r = cluster_wbuild(vp, size, start_lbn, len); 537 /* fall through */ 538 default: 539 /* fall through */ 540 break; 541 } 542 return(r); 543 } 544 545 /* 546 * Do clustered write for FFS. 547 * 548 * Three cases: 549 * 1. Write is not sequential (write asynchronously) 550 * Write is sequential: 551 * 2. beginning of cluster - begin cluster 552 * 3. middle of a cluster - add to cluster 553 * 4. end of a cluster - asynchronously write cluster 554 */ 555 void 556 cluster_write(bp, filesize, seqcount) 557 struct buf *bp; 558 u_quad_t filesize; 559 int seqcount; 560 { 561 struct vnode *vp; 562 daddr_t lbn; 563 int maxclen, cursize; 564 int lblocksize; 565 int async; 566 567 vp = bp->b_vp; 568 if (vp->v_type == VREG) { 569 async = vp->v_mount->mnt_flag & MNT_ASYNC; 570 lblocksize = vp->v_mount->mnt_stat.f_iosize; 571 } else { 572 async = 0; 573 lblocksize = bp->b_bufsize; 574 } 575 lbn = bp->b_lblkno; 576 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 577 578 /* Initialize vnode to beginning of file. */ 579 if (lbn == 0) 580 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 581 582 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 583 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 584 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 585 if (vp->v_clen != 0) { 586 /* 587 * Next block is not sequential. 588 * 589 * If we are not writing at end of file, the process 590 * seeked to another point in the file since its last 591 * write, or we have reached our maximum cluster size, 592 * then push the previous cluster. Otherwise try 593 * reallocating to make it sequential. 594 * 595 * Change to algorithm: only push previous cluster if 596 * it was sequential from the point of view of the 597 * seqcount heuristic, otherwise leave the buffer 598 * intact so we can potentially optimize the I/O 599 * later on in the buf_daemon or update daemon 600 * flush. 601 */ 602 cursize = vp->v_lastw - vp->v_cstart + 1; 603 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 604 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 605 if (!async && seqcount > 0) { 606 cluster_wbuild_wb(vp, lblocksize, 607 vp->v_cstart, cursize); 608 } 609 } else { 610 struct buf **bpp, **endbp; 611 struct cluster_save *buflist; 612 613 buflist = cluster_collectbufs(vp, bp); 614 endbp = &buflist->bs_children 615 [buflist->bs_nchildren - 1]; 616 if (VOP_REALLOCBLKS(vp, buflist)) { 617 /* 618 * Failed, push the previous cluster 619 * if *really* writing sequentially 620 * in the logical file (seqcount > 1), 621 * otherwise delay it in the hopes that 622 * the low level disk driver can 623 * optimize the write ordering. 624 */ 625 for (bpp = buflist->bs_children; 626 bpp < endbp; bpp++) 627 brelse(*bpp); 628 free(buflist, M_SEGMENT); 629 if (seqcount > 1) { 630 cluster_wbuild_wb(vp, 631 lblocksize, vp->v_cstart, 632 cursize); 633 } 634 } else { 635 /* 636 * Succeeded, keep building cluster. 637 */ 638 for (bpp = buflist->bs_children; 639 bpp <= endbp; bpp++) 640 bdwrite(*bpp); 641 free(buflist, M_SEGMENT); 642 vp->v_lastw = lbn; 643 vp->v_lasta = bp->b_blkno; 644 return; 645 } 646 } 647 } 648 /* 649 * Consider beginning a cluster. If at end of file, make 650 * cluster as large as possible, otherwise find size of 651 * existing cluster. 652 */ 653 if ((vp->v_type == VREG) && 654 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 655 (bp->b_blkno == bp->b_lblkno) && 656 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 657 bp->b_blkno == -1)) { 658 bawrite(bp); 659 vp->v_clen = 0; 660 vp->v_lasta = bp->b_blkno; 661 vp->v_cstart = lbn + 1; 662 vp->v_lastw = lbn; 663 return; 664 } 665 vp->v_clen = maxclen; 666 if (!async && maxclen == 0) { /* I/O not contiguous */ 667 vp->v_cstart = lbn + 1; 668 bawrite(bp); 669 } else { /* Wait for rest of cluster */ 670 vp->v_cstart = lbn; 671 bdwrite(bp); 672 } 673 } else if (lbn == vp->v_cstart + vp->v_clen) { 674 /* 675 * At end of cluster, write it out if seqcount tells us we 676 * are operating sequentially, otherwise let the buf or 677 * update daemon handle it. 678 */ 679 bdwrite(bp); 680 if (seqcount > 1) 681 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 682 vp->v_clen = 0; 683 vp->v_cstart = lbn + 1; 684 } else if (vm_page_count_severe()) { 685 /* 686 * We are low on memory, get it going NOW 687 */ 688 bawrite(bp); 689 } else { 690 /* 691 * In the middle of a cluster, so just delay the I/O for now. 692 */ 693 bdwrite(bp); 694 } 695 vp->v_lastw = lbn; 696 vp->v_lasta = bp->b_blkno; 697 } 698 699 700 /* 701 * This is an awful lot like cluster_rbuild...wish they could be combined. 702 * The last lbn argument is the current block on which I/O is being 703 * performed. Check to see that it doesn't fall in the middle of 704 * the current block (if last_bp == NULL). 705 */ 706 int 707 cluster_wbuild(vp, size, start_lbn, len) 708 struct vnode *vp; 709 long size; 710 daddr_t start_lbn; 711 int len; 712 { 713 struct buf *bp, *tbp; 714 int i, j, s; 715 int totalwritten = 0; 716 int dbsize = btodb(size); 717 718 while (len > 0) { 719 s = splbio(); 720 /* 721 * If the buffer is not delayed-write (i.e. dirty), or it 722 * is delayed-write but either locked or inval, it cannot 723 * partake in the clustered write. 724 */ 725 if (((tbp = gbincore(vp, start_lbn)) == NULL) || 726 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 727 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 728 ++start_lbn; 729 --len; 730 splx(s); 731 continue; 732 } 733 bremfree(tbp); 734 tbp->b_flags &= ~B_DONE; 735 splx(s); 736 737 /* 738 * Extra memory in the buffer, punt on this buffer. 739 * XXX we could handle this in most cases, but we would 740 * have to push the extra memory down to after our max 741 * possible cluster size and then potentially pull it back 742 * up if the cluster was terminated prematurely--too much 743 * hassle. 744 */ 745 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 746 (B_CLUSTEROK | B_VMIO)) || 747 (tbp->b_bcount != tbp->b_bufsize) || 748 (tbp->b_bcount != size) || 749 (len == 1) || 750 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 751 totalwritten += tbp->b_bufsize; 752 bawrite(tbp); 753 ++start_lbn; 754 --len; 755 continue; 756 } 757 758 /* 759 * We got a pbuf to make the cluster in. 760 * so initialise it. 761 */ 762 TAILQ_INIT(&bp->b_cluster.cluster_head); 763 bp->b_bcount = 0; 764 bp->b_bufsize = 0; 765 bp->b_npages = 0; 766 if (tbp->b_wcred != NOCRED) { 767 bp->b_wcred = tbp->b_wcred; 768 crhold(bp->b_wcred); 769 } 770 771 bp->b_blkno = tbp->b_blkno; 772 bp->b_lblkno = tbp->b_lblkno; 773 bp->b_offset = tbp->b_offset; 774 bp->b_data = (char *)((vm_offset_t)bp->b_data | 775 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 776 bp->b_flags |= B_CLUSTER | 777 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 778 bp->b_iodone = cluster_callback; 779 pbgetvp(vp, bp); 780 /* 781 * From this location in the file, scan forward to see 782 * if there are buffers with adjacent data that need to 783 * be written as well. 784 */ 785 for (i = 0; i < len; ++i, ++start_lbn) { 786 if (i != 0) { /* If not the first buffer */ 787 s = splbio(); 788 /* 789 * If the adjacent data is not even in core it 790 * can't need to be written. 791 */ 792 if ((tbp = gbincore(vp, start_lbn)) == NULL) { 793 splx(s); 794 break; 795 } 796 797 /* 798 * If it IS in core, but has different 799 * characteristics, or is locked (which 800 * means it could be undergoing a background 801 * I/O or be in a weird state), then don't 802 * cluster with it. 803 */ 804 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 805 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 806 != (B_DELWRI | B_CLUSTEROK | 807 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 808 (tbp->b_flags & B_LOCKED) || 809 tbp->b_wcred != bp->b_wcred || 810 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 811 splx(s); 812 break; 813 } 814 815 /* 816 * Check that the combined cluster 817 * would make sense with regard to pages 818 * and would not be too large 819 */ 820 if ((tbp->b_bcount != size) || 821 ((bp->b_blkno + (dbsize * i)) != 822 tbp->b_blkno) || 823 ((tbp->b_npages + bp->b_npages) > 824 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 825 BUF_UNLOCK(tbp); 826 splx(s); 827 break; 828 } 829 /* 830 * Ok, it's passed all the tests, 831 * so remove it from the free list 832 * and mark it busy. We will use it. 833 */ 834 bremfree(tbp); 835 tbp->b_flags &= ~B_DONE; 836 splx(s); 837 } /* end of code for non-first buffers only */ 838 /* check for latent dependencies to be handled */ 839 if ((LIST_FIRST(&tbp->b_dep)) != NULL) 840 buf_start(tbp); 841 /* 842 * If the IO is via the VM then we do some 843 * special VM hackery. (yuck) 844 */ 845 if (tbp->b_flags & B_VMIO) { 846 vm_page_t m; 847 848 if (i != 0) { /* if not first buffer */ 849 for (j = 0; j < tbp->b_npages; j += 1) { 850 m = tbp->b_pages[j]; 851 if (m->flags & PG_BUSY) { 852 bqrelse(tbp); 853 goto finishcluster; 854 } 855 } 856 } 857 858 for (j = 0; j < tbp->b_npages; j += 1) { 859 m = tbp->b_pages[j]; 860 vm_page_io_start(m); 861 vm_object_pip_add(m->object, 1); 862 if ((bp->b_npages == 0) || 863 (bp->b_pages[bp->b_npages - 1] != m)) { 864 bp->b_pages[bp->b_npages] = m; 865 bp->b_npages++; 866 } 867 } 868 } 869 bp->b_bcount += size; 870 bp->b_bufsize += size; 871 872 s = splbio(); 873 bundirty(tbp); 874 tbp->b_flags &= ~B_DONE; 875 tbp->b_ioflags &= ~BIO_ERROR; 876 tbp->b_flags |= B_ASYNC; 877 tbp->b_iocmd = BIO_WRITE; 878 reassignbuf(tbp, tbp->b_vp); /* put on clean list */ 879 ++tbp->b_vp->v_numoutput; 880 splx(s); 881 BUF_KERNPROC(tbp); 882 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 883 tbp, b_cluster.cluster_entry); 884 } 885 finishcluster: 886 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 887 (vm_page_t *) bp->b_pages, bp->b_npages); 888 if (bp->b_bufsize > bp->b_kvasize) 889 panic( 890 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 891 bp->b_bufsize, bp->b_kvasize); 892 bp->b_kvasize = bp->b_bufsize; 893 totalwritten += bp->b_bufsize; 894 bp->b_dirtyoff = 0; 895 bp->b_dirtyend = bp->b_bufsize; 896 bawrite(bp); 897 898 len -= i; 899 } 900 return totalwritten; 901 } 902 903 /* 904 * Collect together all the buffers in a cluster. 905 * Plus add one additional buffer. 906 */ 907 static struct cluster_save * 908 cluster_collectbufs(vp, last_bp) 909 struct vnode *vp; 910 struct buf *last_bp; 911 { 912 struct cluster_save *buflist; 913 struct buf *bp; 914 daddr_t lbn; 915 int i, len; 916 917 len = vp->v_lastw - vp->v_cstart + 1; 918 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 919 M_SEGMENT, M_WAITOK); 920 buflist->bs_nchildren = 0; 921 buflist->bs_children = (struct buf **) (buflist + 1); 922 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 923 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 924 buflist->bs_children[i] = bp; 925 if (bp->b_blkno == bp->b_lblkno) 926 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, 927 NULL, NULL); 928 } 929 buflist->bs_children[i] = bp = last_bp; 930 if (bp->b_blkno == bp->b_lblkno) 931 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, 932 NULL, NULL); 933 buflist->bs_nchildren = i + 1; 934 return (buflist); 935 } 936