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 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include "opt_debug_cluster.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/kernel.h> 42 #include <sys/proc.h> 43 #include <sys/bio.h> 44 #include <sys/buf.h> 45 #include <sys/vnode.h> 46 #include <sys/malloc.h> 47 #include <sys/mount.h> 48 #include <sys/resourcevar.h> 49 #include <sys/vmmeter.h> 50 #include <vm/vm.h> 51 #include <vm/vm_object.h> 52 #include <vm/vm_page.h> 53 #include <sys/sysctl.h> 54 55 #if defined(CLUSTERDEBUG) 56 static int rcluster= 0; 57 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, 58 "Debug VFS clustering code"); 59 #endif 60 61 static MALLOC_DEFINE(M_SEGMENT, "cluster_save buffer", "cluster_save buffer"); 62 63 static struct cluster_save * 64 cluster_collectbufs(struct vnode *vp, struct buf *last_bp); 65 static struct buf * 66 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 67 daddr_t blkno, long size, int run, struct buf *fbp); 68 static void cluster_callback(struct buf *); 69 70 static int write_behind = 1; 71 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 72 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 73 74 static int read_max = 8; 75 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 76 "Cluster read-ahead max block count"); 77 78 /* Page expended to mark partially backed buffers */ 79 extern vm_page_t bogus_page; 80 81 /* 82 * Read data to a buf, including read-ahead if we find this to be beneficial. 83 * cluster_read 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 maxra, racluster; 99 int error, ncontig; 100 int i; 101 102 error = 0; 103 104 /* 105 * Try to limit the amount of read-ahead by a few 106 * ad-hoc parameters. This needs work!!! 107 */ 108 racluster = vp->v_mount->mnt_iosize_max / size; 109 maxra = seqcount; 110 maxra = min(read_max, maxra); 111 maxra = min(nbuf/8, maxra); 112 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 113 maxra = (filesize / size) - lblkno; 114 115 /* 116 * get the requested block 117 */ 118 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0); 119 origblkno = lblkno; 120 121 /* 122 * if it is in the cache, then check to see if the reads have been 123 * sequential. If they have, then try some read-ahead, otherwise 124 * back-off on prospective read-aheads. 125 */ 126 if (bp->b_flags & B_CACHE) { 127 if (!seqcount) { 128 return 0; 129 } else if ((bp->b_flags & B_RAM) == 0) { 130 return 0; 131 } else { 132 bp->b_flags &= ~B_RAM; 133 VI_LOCK(vp); 134 for (i = 1; i < maxra; i++) { 135 /* 136 * Stop if the buffer does not exist or it 137 * is invalid (about to go away?) 138 */ 139 rbp = gbincore(&vp->v_bufobj, lblkno+i); 140 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 141 break; 142 143 /* 144 * Set another read-ahead mark so we know 145 * to check again. 146 */ 147 if (((i % racluster) == (racluster - 1)) || 148 (i == (maxra - 1))) 149 rbp->b_flags |= B_RAM; 150 } 151 VI_UNLOCK(vp); 152 if (i >= maxra) { 153 return 0; 154 } 155 lblkno += i; 156 } 157 reqbp = bp = NULL; 158 /* 159 * If it isn't in the cache, then get a chunk from 160 * disk if sequential, otherwise just get the block. 161 */ 162 } else { 163 off_t firstread = bp->b_offset; 164 int nblks; 165 166 KASSERT(bp->b_offset != NOOFFSET, 167 ("cluster_read: no buffer offset")); 168 169 ncontig = 0; 170 171 /* 172 * Compute the total number of blocks that we should read 173 * synchronously. 174 */ 175 if (firstread + totread > filesize) 176 totread = filesize - firstread; 177 nblks = howmany(totread, size); 178 if (nblks > racluster) 179 nblks = racluster; 180 181 /* 182 * Now compute the number of contiguous blocks. 183 */ 184 if (nblks > 1) { 185 error = VOP_BMAP(vp, lblkno, NULL, 186 &blkno, &ncontig, NULL); 187 /* 188 * If this failed to map just do the original block. 189 */ 190 if (error || blkno == -1) 191 ncontig = 0; 192 } 193 194 /* 195 * If we have contiguous data available do a cluster 196 * otherwise just read the requested block. 197 */ 198 if (ncontig) { 199 /* Account for our first block. */ 200 ncontig = min(ncontig + 1, nblks); 201 if (ncontig < nblks) 202 nblks = ncontig; 203 bp = cluster_rbuild(vp, filesize, lblkno, 204 blkno, size, nblks, bp); 205 lblkno += (bp->b_bufsize / size); 206 } else { 207 bp->b_flags |= B_RAM; 208 bp->b_iocmd = BIO_READ; 209 lblkno += 1; 210 } 211 } 212 213 /* 214 * handle the synchronous read so that it is available ASAP. 215 */ 216 if (bp) { 217 if ((bp->b_flags & B_CLUSTER) == 0) { 218 vfs_busy_pages(bp, 0); 219 } 220 bp->b_flags &= ~B_INVAL; 221 bp->b_ioflags &= ~BIO_ERROR; 222 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 223 BUF_KERNPROC(bp); 224 bp->b_iooffset = dbtob(bp->b_blkno); 225 bstrategy(bp); 226 curproc->p_stats->p_ru.ru_inblock++; 227 } 228 229 /* 230 * If we have been doing sequential I/O, then do some read-ahead. 231 */ 232 while (lblkno < (origblkno + maxra)) { 233 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 234 if (error) 235 break; 236 237 if (blkno == -1) 238 break; 239 240 /* 241 * We could throttle ncontig here by maxra but we might as 242 * well read the data if it is contiguous. We're throttled 243 * by racluster anyway. 244 */ 245 if (ncontig) { 246 ncontig = min(ncontig + 1, racluster); 247 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 248 size, ncontig, NULL); 249 lblkno += (rbp->b_bufsize / size); 250 if (rbp->b_flags & B_DELWRI) { 251 bqrelse(rbp); 252 continue; 253 } 254 } else { 255 rbp = getblk(vp, lblkno, size, 0, 0, 0); 256 lblkno += 1; 257 if (rbp->b_flags & B_DELWRI) { 258 bqrelse(rbp); 259 continue; 260 } 261 rbp->b_flags |= B_ASYNC | B_RAM; 262 rbp->b_iocmd = BIO_READ; 263 rbp->b_blkno = blkno; 264 } 265 if (rbp->b_flags & B_CACHE) { 266 rbp->b_flags &= ~B_ASYNC; 267 bqrelse(rbp); 268 continue; 269 } 270 if ((rbp->b_flags & B_CLUSTER) == 0) { 271 vfs_busy_pages(rbp, 0); 272 } 273 rbp->b_flags &= ~B_INVAL; 274 rbp->b_ioflags &= ~BIO_ERROR; 275 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 276 BUF_KERNPROC(rbp); 277 rbp->b_iooffset = dbtob(rbp->b_blkno); 278 bstrategy(rbp); 279 curproc->p_stats->p_ru.ru_inblock++; 280 } 281 282 if (reqbp) 283 return (bufwait(reqbp)); 284 else 285 return (error); 286 } 287 288 /* 289 * If blocks are contiguous on disk, use this to provide clustered 290 * read ahead. We will read as many blocks as possible sequentially 291 * and then parcel them up into logical blocks in the buffer hash table. 292 */ 293 static struct buf * 294 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 295 struct vnode *vp; 296 u_quad_t filesize; 297 daddr_t lbn; 298 daddr_t blkno; 299 long size; 300 int run; 301 struct buf *fbp; 302 { 303 struct buf *bp, *tbp; 304 daddr_t bn; 305 int i, inc, j; 306 307 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 308 ("cluster_rbuild: size %ld != filesize %jd\n", 309 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 310 311 /* 312 * avoid a division 313 */ 314 while ((u_quad_t) size * (lbn + run) > filesize) { 315 --run; 316 } 317 318 if (fbp) { 319 tbp = fbp; 320 tbp->b_iocmd = BIO_READ; 321 } else { 322 tbp = getblk(vp, lbn, size, 0, 0, 0); 323 if (tbp->b_flags & B_CACHE) 324 return tbp; 325 tbp->b_flags |= B_ASYNC | B_RAM; 326 tbp->b_iocmd = BIO_READ; 327 } 328 329 tbp->b_blkno = blkno; 330 if( (tbp->b_flags & B_MALLOC) || 331 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 332 return tbp; 333 334 bp = trypbuf(&cluster_pbuf_freecnt); 335 if (bp == 0) 336 return tbp; 337 338 /* 339 * We are synthesizing a buffer out of vm_page_t's, but 340 * if the block size is not page aligned then the starting 341 * address may not be either. Inherit the b_data offset 342 * from the original buffer. 343 */ 344 bp->b_data = (char *)((vm_offset_t)bp->b_data | 345 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 346 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 347 bp->b_iocmd = BIO_READ; 348 bp->b_iodone = cluster_callback; 349 bp->b_blkno = blkno; 350 bp->b_lblkno = lbn; 351 bp->b_offset = tbp->b_offset; 352 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 353 pbgetvp(vp, bp); 354 355 TAILQ_INIT(&bp->b_cluster.cluster_head); 356 357 bp->b_bcount = 0; 358 bp->b_bufsize = 0; 359 bp->b_npages = 0; 360 361 inc = btodb(size); 362 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 363 if (i != 0) { 364 if ((bp->b_npages * PAGE_SIZE) + 365 round_page(size) > vp->v_mount->mnt_iosize_max) { 366 break; 367 } 368 369 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT); 370 371 /* Don't wait around for locked bufs. */ 372 if (tbp == NULL) 373 break; 374 375 /* 376 * Stop scanning if the buffer is fully valid 377 * (marked B_CACHE), or locked (may be doing a 378 * background write), or if the buffer is not 379 * VMIO backed. The clustering code can only deal 380 * with VMIO-backed buffers. 381 */ 382 VI_LOCK(vp); 383 if ((tbp->b_vflags & BV_BKGRDINPROG) || 384 (tbp->b_flags & B_CACHE) || 385 (tbp->b_flags & B_VMIO) == 0) { 386 VI_UNLOCK(vp); 387 bqrelse(tbp); 388 break; 389 } 390 VI_UNLOCK(vp); 391 392 /* 393 * The buffer must be completely invalid in order to 394 * take part in the cluster. If it is partially valid 395 * then we stop. 396 */ 397 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 398 for (j = 0;j < tbp->b_npages; j++) { 399 VM_OBJECT_LOCK_ASSERT(tbp->b_pages[j]->object, 400 MA_OWNED); 401 if (tbp->b_pages[j]->valid) 402 break; 403 } 404 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 405 if (j != tbp->b_npages) { 406 bqrelse(tbp); 407 break; 408 } 409 410 /* 411 * Set a read-ahead mark as appropriate 412 */ 413 if ((fbp && (i == 1)) || (i == (run - 1))) 414 tbp->b_flags |= B_RAM; 415 416 /* 417 * Set the buffer up for an async read (XXX should 418 * we do this only if we do not wind up brelse()ing?). 419 * Set the block number if it isn't set, otherwise 420 * if it is make sure it matches the block number we 421 * expect. 422 */ 423 tbp->b_flags |= B_ASYNC; 424 tbp->b_iocmd = BIO_READ; 425 if (tbp->b_blkno == tbp->b_lblkno) { 426 tbp->b_blkno = bn; 427 } else if (tbp->b_blkno != bn) { 428 brelse(tbp); 429 break; 430 } 431 } 432 /* 433 * XXX fbp from caller may not be B_ASYNC, but we are going 434 * to biodone() it in cluster_callback() anyway 435 */ 436 BUF_KERNPROC(tbp); 437 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 438 tbp, b_cluster.cluster_entry); 439 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 440 for (j = 0; j < tbp->b_npages; j += 1) { 441 vm_page_t m; 442 m = tbp->b_pages[j]; 443 vm_page_io_start(m); 444 vm_object_pip_add(m->object, 1); 445 if ((bp->b_npages == 0) || 446 (bp->b_pages[bp->b_npages-1] != m)) { 447 bp->b_pages[bp->b_npages] = m; 448 bp->b_npages++; 449 } 450 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 451 tbp->b_pages[j] = bogus_page; 452 } 453 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 454 /* 455 * XXX shouldn't this be += size for both, like in 456 * cluster_wbuild()? 457 * 458 * Don't inherit tbp->b_bufsize as it may be larger due to 459 * a non-page-aligned size. Instead just aggregate using 460 * 'size'. 461 */ 462 if (tbp->b_bcount != size) 463 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 464 if (tbp->b_bufsize != size) 465 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 466 bp->b_bcount += size; 467 bp->b_bufsize += size; 468 } 469 470 /* 471 * Fully valid pages in the cluster are already good and do not need 472 * to be re-read from disk. Replace the page with bogus_page 473 */ 474 VM_OBJECT_LOCK(bp->b_bufobj->bo_object); 475 for (j = 0; j < bp->b_npages; j++) { 476 VM_OBJECT_LOCK_ASSERT(bp->b_pages[j]->object, MA_OWNED); 477 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 478 VM_PAGE_BITS_ALL) { 479 bp->b_pages[j] = bogus_page; 480 } 481 } 482 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object); 483 if (bp->b_bufsize > bp->b_kvasize) 484 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 485 bp->b_bufsize, bp->b_kvasize); 486 bp->b_kvasize = bp->b_bufsize; 487 488 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 489 (vm_page_t *)bp->b_pages, bp->b_npages); 490 return (bp); 491 } 492 493 /* 494 * Cleanup after a clustered read or write. 495 * This is complicated by the fact that any of the buffers might have 496 * extra memory (if there were no empty buffer headers at allocbuf time) 497 * that we will need to shift around. 498 */ 499 static void 500 cluster_callback(bp) 501 struct buf *bp; 502 { 503 struct buf *nbp, *tbp; 504 int error = 0; 505 506 /* 507 * Must propogate errors to all the components. 508 */ 509 if (bp->b_ioflags & BIO_ERROR) 510 error = bp->b_error; 511 512 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 513 /* 514 * Move memory from the large cluster buffer into the component 515 * buffers and mark IO as done on these. 516 */ 517 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 518 tbp; tbp = nbp) { 519 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 520 if (error) { 521 tbp->b_ioflags |= BIO_ERROR; 522 tbp->b_error = error; 523 } else { 524 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 525 tbp->b_flags &= ~B_INVAL; 526 tbp->b_ioflags &= ~BIO_ERROR; 527 /* 528 * XXX the bdwrite()/bqrelse() issued during 529 * cluster building clears B_RELBUF (see bqrelse() 530 * comment). If direct I/O was specified, we have 531 * to restore it here to allow the buffer and VM 532 * to be freed. 533 */ 534 if (tbp->b_flags & B_DIRECT) 535 tbp->b_flags |= B_RELBUF; 536 } 537 bufdone(tbp); 538 } 539 pbrelvp(bp); 540 relpbuf(bp, &cluster_pbuf_freecnt); 541 } 542 543 /* 544 * cluster_wbuild_wb: 545 * 546 * Implement modified write build for cluster. 547 * 548 * write_behind = 0 write behind disabled 549 * write_behind = 1 write behind normal (default) 550 * write_behind = 2 write behind backed-off 551 */ 552 553 static __inline int 554 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 555 { 556 int r = 0; 557 558 switch(write_behind) { 559 case 2: 560 if (start_lbn < len) 561 break; 562 start_lbn -= len; 563 /* FALLTHROUGH */ 564 case 1: 565 r = cluster_wbuild(vp, size, start_lbn, len); 566 /* FALLTHROUGH */ 567 default: 568 /* FALLTHROUGH */ 569 break; 570 } 571 return(r); 572 } 573 574 /* 575 * Do clustered write for FFS. 576 * 577 * Three cases: 578 * 1. Write is not sequential (write asynchronously) 579 * Write is sequential: 580 * 2. beginning of cluster - begin cluster 581 * 3. middle of a cluster - add to cluster 582 * 4. end of a cluster - asynchronously write cluster 583 */ 584 void 585 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount) 586 { 587 daddr_t lbn; 588 int maxclen, cursize; 589 int lblocksize; 590 int async; 591 592 if (vp->v_type == VREG) { 593 async = vp->v_mount->mnt_flag & MNT_ASYNC; 594 lblocksize = vp->v_mount->mnt_stat.f_iosize; 595 } else { 596 async = 0; 597 lblocksize = bp->b_bufsize; 598 } 599 lbn = bp->b_lblkno; 600 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 601 602 /* Initialize vnode to beginning of file. */ 603 if (lbn == 0) 604 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 605 606 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 607 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 608 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 609 if (vp->v_clen != 0) { 610 /* 611 * Next block is not sequential. 612 * 613 * If we are not writing at end of file, the process 614 * seeked to another point in the file since its last 615 * write, or we have reached our maximum cluster size, 616 * then push the previous cluster. Otherwise try 617 * reallocating to make it sequential. 618 * 619 * Change to algorithm: only push previous cluster if 620 * it was sequential from the point of view of the 621 * seqcount heuristic, otherwise leave the buffer 622 * intact so we can potentially optimize the I/O 623 * later on in the buf_daemon or update daemon 624 * flush. 625 */ 626 cursize = vp->v_lastw - vp->v_cstart + 1; 627 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 628 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 629 if (!async && seqcount > 0) { 630 cluster_wbuild_wb(vp, lblocksize, 631 vp->v_cstart, cursize); 632 } 633 } else { 634 struct buf **bpp, **endbp; 635 struct cluster_save *buflist; 636 637 buflist = cluster_collectbufs(vp, bp); 638 endbp = &buflist->bs_children 639 [buflist->bs_nchildren - 1]; 640 if (VOP_REALLOCBLKS(vp, buflist)) { 641 /* 642 * Failed, push the previous cluster 643 * if *really* writing sequentially 644 * in the logical file (seqcount > 1), 645 * otherwise delay it in the hopes that 646 * the low level disk driver can 647 * optimize the write ordering. 648 */ 649 for (bpp = buflist->bs_children; 650 bpp < endbp; bpp++) 651 brelse(*bpp); 652 free(buflist, M_SEGMENT); 653 if (seqcount > 1) { 654 cluster_wbuild_wb(vp, 655 lblocksize, vp->v_cstart, 656 cursize); 657 } 658 } else { 659 /* 660 * Succeeded, keep building cluster. 661 */ 662 for (bpp = buflist->bs_children; 663 bpp <= endbp; bpp++) 664 bdwrite(*bpp); 665 free(buflist, M_SEGMENT); 666 vp->v_lastw = lbn; 667 vp->v_lasta = bp->b_blkno; 668 return; 669 } 670 } 671 } 672 /* 673 * Consider beginning a cluster. If at end of file, make 674 * cluster as large as possible, otherwise find size of 675 * existing cluster. 676 */ 677 if ((vp->v_type == VREG) && 678 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 679 (bp->b_blkno == bp->b_lblkno) && 680 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 681 bp->b_blkno == -1)) { 682 bawrite(bp); 683 vp->v_clen = 0; 684 vp->v_lasta = bp->b_blkno; 685 vp->v_cstart = lbn + 1; 686 vp->v_lastw = lbn; 687 return; 688 } 689 vp->v_clen = maxclen; 690 if (!async && maxclen == 0) { /* I/O not contiguous */ 691 vp->v_cstart = lbn + 1; 692 bawrite(bp); 693 } else { /* Wait for rest of cluster */ 694 vp->v_cstart = lbn; 695 bdwrite(bp); 696 } 697 } else if (lbn == vp->v_cstart + vp->v_clen) { 698 /* 699 * At end of cluster, write it out if seqcount tells us we 700 * are operating sequentially, otherwise let the buf or 701 * update daemon handle it. 702 */ 703 bdwrite(bp); 704 if (seqcount > 1) 705 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 706 vp->v_clen = 0; 707 vp->v_cstart = lbn + 1; 708 } else if (vm_page_count_severe()) { 709 /* 710 * We are low on memory, get it going NOW 711 */ 712 bawrite(bp); 713 } else { 714 /* 715 * In the middle of a cluster, so just delay the I/O for now. 716 */ 717 bdwrite(bp); 718 } 719 vp->v_lastw = lbn; 720 vp->v_lasta = bp->b_blkno; 721 } 722 723 724 /* 725 * This is an awful lot like cluster_rbuild...wish they could be combined. 726 * The last lbn argument is the current block on which I/O is being 727 * performed. Check to see that it doesn't fall in the middle of 728 * the current block (if last_bp == NULL). 729 */ 730 int 731 cluster_wbuild(vp, size, start_lbn, len) 732 struct vnode *vp; 733 long size; 734 daddr_t start_lbn; 735 int len; 736 { 737 struct buf *bp, *tbp; 738 int i, j; 739 int totalwritten = 0; 740 int dbsize = btodb(size); 741 742 while (len > 0) { 743 /* 744 * If the buffer is not delayed-write (i.e. dirty), or it 745 * is delayed-write but either locked or inval, it cannot 746 * partake in the clustered write. 747 */ 748 VI_LOCK(vp); 749 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 750 (tbp->b_vflags & BV_BKGRDINPROG)) { 751 VI_UNLOCK(vp); 752 ++start_lbn; 753 --len; 754 continue; 755 } 756 if (BUF_LOCK(tbp, 757 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, VI_MTX(vp))) { 758 ++start_lbn; 759 --len; 760 continue; 761 } 762 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 763 BUF_UNLOCK(tbp); 764 ++start_lbn; 765 --len; 766 continue; 767 } 768 bremfree(tbp); 769 tbp->b_flags &= ~B_DONE; 770 771 /* 772 * Extra memory in the buffer, punt on this buffer. 773 * XXX we could handle this in most cases, but we would 774 * have to push the extra memory down to after our max 775 * possible cluster size and then potentially pull it back 776 * up if the cluster was terminated prematurely--too much 777 * hassle. 778 */ 779 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 780 (B_CLUSTEROK | B_VMIO)) || 781 (tbp->b_bcount != tbp->b_bufsize) || 782 (tbp->b_bcount != size) || 783 (len == 1) || 784 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 785 totalwritten += tbp->b_bufsize; 786 bawrite(tbp); 787 ++start_lbn; 788 --len; 789 continue; 790 } 791 792 /* 793 * We got a pbuf to make the cluster in. 794 * so initialise it. 795 */ 796 TAILQ_INIT(&bp->b_cluster.cluster_head); 797 bp->b_bcount = 0; 798 bp->b_bufsize = 0; 799 bp->b_npages = 0; 800 if (tbp->b_wcred != NOCRED) 801 bp->b_wcred = crhold(tbp->b_wcred); 802 803 bp->b_blkno = tbp->b_blkno; 804 bp->b_lblkno = tbp->b_lblkno; 805 bp->b_offset = tbp->b_offset; 806 807 /* 808 * We are synthesizing a buffer out of vm_page_t's, but 809 * if the block size is not page aligned then the starting 810 * address may not be either. Inherit the b_data offset 811 * from the original buffer. 812 */ 813 bp->b_data = (char *)((vm_offset_t)bp->b_data | 814 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 815 bp->b_flags |= B_CLUSTER | 816 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 817 bp->b_iodone = cluster_callback; 818 pbgetvp(vp, bp); 819 /* 820 * From this location in the file, scan forward to see 821 * if there are buffers with adjacent data that need to 822 * be written as well. 823 */ 824 for (i = 0; i < len; ++i, ++start_lbn) { 825 if (i != 0) { /* If not the first buffer */ 826 /* 827 * If the adjacent data is not even in core it 828 * can't need to be written. 829 */ 830 VI_LOCK(vp); 831 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 832 (tbp->b_vflags & BV_BKGRDINPROG)) { 833 VI_UNLOCK(vp); 834 break; 835 } 836 837 /* 838 * If it IS in core, but has different 839 * characteristics, or is locked (which 840 * means it could be undergoing a background 841 * I/O or be in a weird state), then don't 842 * cluster with it. 843 */ 844 if (BUF_LOCK(tbp, 845 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 846 VI_MTX(vp))) 847 break; 848 849 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 850 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 851 != (B_DELWRI | B_CLUSTEROK | 852 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 853 tbp->b_wcred != bp->b_wcred) { 854 BUF_UNLOCK(tbp); 855 break; 856 } 857 858 /* 859 * Check that the combined cluster 860 * would make sense with regard to pages 861 * and would not be too large 862 */ 863 if ((tbp->b_bcount != size) || 864 ((bp->b_blkno + (dbsize * i)) != 865 tbp->b_blkno) || 866 ((tbp->b_npages + bp->b_npages) > 867 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 868 BUF_UNLOCK(tbp); 869 break; 870 } 871 /* 872 * Ok, it's passed all the tests, 873 * so remove it from the free list 874 * and mark it busy. We will use it. 875 */ 876 bremfree(tbp); 877 tbp->b_flags &= ~B_DONE; 878 } /* end of code for non-first buffers only */ 879 /* check for latent dependencies to be handled */ 880 if ((LIST_FIRST(&tbp->b_dep)) != NULL) { 881 tbp->b_iocmd = BIO_WRITE; 882 buf_start(tbp); 883 } 884 /* 885 * If the IO is via the VM then we do some 886 * special VM hackery (yuck). Since the buffer's 887 * block size may not be page-aligned it is possible 888 * for a page to be shared between two buffers. We 889 * have to get rid of the duplication when building 890 * the cluster. 891 */ 892 if (tbp->b_flags & B_VMIO) { 893 vm_page_t m; 894 895 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 896 if (i != 0) { /* if not first buffer */ 897 for (j = 0; j < tbp->b_npages; j += 1) { 898 m = tbp->b_pages[j]; 899 if (m->flags & PG_BUSY) { 900 VM_OBJECT_UNLOCK( 901 tbp->b_object); 902 bqrelse(tbp); 903 goto finishcluster; 904 } 905 } 906 } 907 for (j = 0; j < tbp->b_npages; j += 1) { 908 m = tbp->b_pages[j]; 909 vm_page_io_start(m); 910 vm_object_pip_add(m->object, 1); 911 if ((bp->b_npages == 0) || 912 (bp->b_pages[bp->b_npages - 1] != m)) { 913 bp->b_pages[bp->b_npages] = m; 914 bp->b_npages++; 915 } 916 } 917 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 918 } 919 bp->b_bcount += size; 920 bp->b_bufsize += size; 921 bundirty(tbp); 922 tbp->b_flags &= ~B_DONE; 923 tbp->b_ioflags &= ~BIO_ERROR; 924 tbp->b_flags |= B_ASYNC; 925 tbp->b_iocmd = BIO_WRITE; 926 reassignbuf(tbp); /* put on clean list */ 927 bufobj_wref(tbp->b_bufobj); 928 BUF_KERNPROC(tbp); 929 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 930 tbp, b_cluster.cluster_entry); 931 } 932 finishcluster: 933 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 934 (vm_page_t *) bp->b_pages, bp->b_npages); 935 if (bp->b_bufsize > bp->b_kvasize) 936 panic( 937 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 938 bp->b_bufsize, bp->b_kvasize); 939 bp->b_kvasize = bp->b_bufsize; 940 totalwritten += bp->b_bufsize; 941 bp->b_dirtyoff = 0; 942 bp->b_dirtyend = bp->b_bufsize; 943 bawrite(bp); 944 945 len -= i; 946 } 947 return totalwritten; 948 } 949 950 /* 951 * Collect together all the buffers in a cluster. 952 * Plus add one additional buffer. 953 */ 954 static struct cluster_save * 955 cluster_collectbufs(vp, last_bp) 956 struct vnode *vp; 957 struct buf *last_bp; 958 { 959 struct cluster_save *buflist; 960 struct buf *bp; 961 daddr_t lbn; 962 int i, len; 963 964 len = vp->v_lastw - vp->v_cstart + 1; 965 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 966 M_SEGMENT, M_WAITOK); 967 buflist->bs_nchildren = 0; 968 buflist->bs_children = (struct buf **) (buflist + 1); 969 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 970 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 971 buflist->bs_children[i] = bp; 972 if (bp->b_blkno == bp->b_lblkno) 973 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 974 NULL, NULL); 975 } 976 buflist->bs_children[i] = bp = last_bp; 977 if (bp->b_blkno == bp->b_lblkno) 978 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 979 buflist->bs_nchildren = i + 1; 980 return (buflist); 981 } 982