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 * Number of physical bufs (pbufs) this subsystem is allowed. 83 * Manipulated by vm_pager.c 84 */ 85 extern int cluster_pbuf_freecnt; 86 87 /* 88 * Read data to a buf, including read-ahead if we find this to be beneficial. 89 * cluster_read replaces bread. 90 */ 91 int 92 cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp) 93 struct vnode *vp; 94 u_quad_t filesize; 95 daddr_t lblkno; 96 long size; 97 struct ucred *cred; 98 long totread; 99 int seqcount; 100 struct buf **bpp; 101 { 102 struct buf *bp, *rbp, *reqbp; 103 daddr_t blkno, origblkno; 104 int maxra, racluster; 105 int error, ncontig; 106 int i; 107 108 error = 0; 109 110 /* 111 * Try to limit the amount of read-ahead by a few 112 * ad-hoc parameters. This needs work!!! 113 */ 114 racluster = vp->v_mount->mnt_iosize_max / size; 115 maxra = seqcount; 116 maxra = min(read_max, maxra); 117 maxra = min(nbuf/8, maxra); 118 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 119 maxra = (filesize / size) - lblkno; 120 121 /* 122 * get the requested block 123 */ 124 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0); 125 origblkno = lblkno; 126 127 /* 128 * if it is in the cache, then check to see if the reads have been 129 * sequential. If they have, then try some read-ahead, otherwise 130 * back-off on prospective read-aheads. 131 */ 132 if (bp->b_flags & B_CACHE) { 133 if (!seqcount) { 134 return 0; 135 } else if ((bp->b_flags & B_RAM) == 0) { 136 return 0; 137 } else { 138 bp->b_flags &= ~B_RAM; 139 VI_LOCK(vp); 140 for (i = 1; i < maxra; i++) { 141 /* 142 * Stop if the buffer does not exist or it 143 * is invalid (about to go away?) 144 */ 145 rbp = gbincore(&vp->v_bufobj, lblkno+i); 146 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 147 break; 148 149 /* 150 * Set another read-ahead mark so we know 151 * to check again. 152 */ 153 if (((i % racluster) == (racluster - 1)) || 154 (i == (maxra - 1))) 155 rbp->b_flags |= B_RAM; 156 } 157 VI_UNLOCK(vp); 158 if (i >= maxra) { 159 return 0; 160 } 161 lblkno += i; 162 } 163 reqbp = bp = NULL; 164 /* 165 * If it isn't in the cache, then get a chunk from 166 * disk if sequential, otherwise just get the block. 167 */ 168 } else { 169 off_t firstread = bp->b_offset; 170 int nblks; 171 172 KASSERT(bp->b_offset != NOOFFSET, 173 ("cluster_read: no buffer offset")); 174 175 ncontig = 0; 176 177 /* 178 * Compute the total number of blocks that we should read 179 * synchronously. 180 */ 181 if (firstread + totread > filesize) 182 totread = filesize - firstread; 183 nblks = howmany(totread, size); 184 if (nblks > racluster) 185 nblks = racluster; 186 187 /* 188 * Now compute the number of contiguous blocks. 189 */ 190 if (nblks > 1) { 191 error = VOP_BMAP(vp, lblkno, NULL, 192 &blkno, &ncontig, NULL); 193 /* 194 * If this failed to map just do the original block. 195 */ 196 if (error || blkno == -1) 197 ncontig = 0; 198 } 199 200 /* 201 * If we have contiguous data available do a cluster 202 * otherwise just read the requested block. 203 */ 204 if (ncontig) { 205 /* Account for our first block. */ 206 ncontig = min(ncontig + 1, nblks); 207 if (ncontig < nblks) 208 nblks = ncontig; 209 bp = cluster_rbuild(vp, filesize, lblkno, 210 blkno, size, nblks, bp); 211 lblkno += (bp->b_bufsize / size); 212 } else { 213 bp->b_flags |= B_RAM; 214 bp->b_iocmd = BIO_READ; 215 lblkno += 1; 216 } 217 } 218 219 /* 220 * handle the synchronous read so that it is available ASAP. 221 */ 222 if (bp) { 223 if ((bp->b_flags & B_CLUSTER) == 0) { 224 vfs_busy_pages(bp, 0); 225 } 226 bp->b_flags &= ~B_INVAL; 227 bp->b_ioflags &= ~BIO_ERROR; 228 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 229 BUF_KERNPROC(bp); 230 bp->b_iooffset = dbtob(bp->b_blkno); 231 bstrategy(bp); 232 curproc->p_stats->p_ru.ru_inblock++; 233 } 234 235 /* 236 * If we have been doing sequential I/O, then do some read-ahead. 237 */ 238 while (lblkno < (origblkno + maxra)) { 239 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 240 if (error) 241 break; 242 243 if (blkno == -1) 244 break; 245 246 /* 247 * We could throttle ncontig here by maxra but we might as 248 * well read the data if it is contiguous. We're throttled 249 * by racluster anyway. 250 */ 251 if (ncontig) { 252 ncontig = min(ncontig + 1, racluster); 253 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 254 size, ncontig, NULL); 255 lblkno += (rbp->b_bufsize / size); 256 if (rbp->b_flags & B_DELWRI) { 257 bqrelse(rbp); 258 continue; 259 } 260 } else { 261 rbp = getblk(vp, lblkno, size, 0, 0, 0); 262 lblkno += 1; 263 if (rbp->b_flags & B_DELWRI) { 264 bqrelse(rbp); 265 continue; 266 } 267 rbp->b_flags |= B_ASYNC | B_RAM; 268 rbp->b_iocmd = BIO_READ; 269 rbp->b_blkno = blkno; 270 } 271 if (rbp->b_flags & B_CACHE) { 272 rbp->b_flags &= ~B_ASYNC; 273 bqrelse(rbp); 274 continue; 275 } 276 if ((rbp->b_flags & B_CLUSTER) == 0) { 277 vfs_busy_pages(rbp, 0); 278 } 279 rbp->b_flags &= ~B_INVAL; 280 rbp->b_ioflags &= ~BIO_ERROR; 281 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 282 BUF_KERNPROC(rbp); 283 rbp->b_iooffset = dbtob(rbp->b_blkno); 284 bstrategy(rbp); 285 curproc->p_stats->p_ru.ru_inblock++; 286 } 287 288 if (reqbp) 289 return (bufwait(reqbp)); 290 else 291 return (error); 292 } 293 294 /* 295 * If blocks are contiguous on disk, use this to provide clustered 296 * read ahead. We will read as many blocks as possible sequentially 297 * and then parcel them up into logical blocks in the buffer hash table. 298 */ 299 static struct buf * 300 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 301 struct vnode *vp; 302 u_quad_t filesize; 303 daddr_t lbn; 304 daddr_t blkno; 305 long size; 306 int run; 307 struct buf *fbp; 308 { 309 struct buf *bp, *tbp; 310 daddr_t bn; 311 int i, inc, j; 312 313 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 314 ("cluster_rbuild: size %ld != filesize %jd\n", 315 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 316 317 /* 318 * avoid a division 319 */ 320 while ((u_quad_t) size * (lbn + run) > filesize) { 321 --run; 322 } 323 324 if (fbp) { 325 tbp = fbp; 326 tbp->b_iocmd = BIO_READ; 327 } else { 328 tbp = getblk(vp, lbn, size, 0, 0, 0); 329 if (tbp->b_flags & B_CACHE) 330 return tbp; 331 tbp->b_flags |= B_ASYNC | B_RAM; 332 tbp->b_iocmd = BIO_READ; 333 } 334 335 tbp->b_blkno = blkno; 336 if( (tbp->b_flags & B_MALLOC) || 337 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 338 return tbp; 339 340 bp = trypbuf(&cluster_pbuf_freecnt); 341 if (bp == 0) 342 return tbp; 343 344 /* 345 * We are synthesizing a buffer out of vm_page_t's, but 346 * if the block size is not page aligned then the starting 347 * address may not be either. Inherit the b_data offset 348 * from the original buffer. 349 */ 350 bp->b_data = (char *)((vm_offset_t)bp->b_data | 351 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 352 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 353 bp->b_iocmd = BIO_READ; 354 bp->b_iodone = cluster_callback; 355 bp->b_blkno = blkno; 356 bp->b_lblkno = lbn; 357 bp->b_offset = tbp->b_offset; 358 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 359 pbgetvp(vp, bp); 360 361 TAILQ_INIT(&bp->b_cluster.cluster_head); 362 363 bp->b_bcount = 0; 364 bp->b_bufsize = 0; 365 bp->b_npages = 0; 366 367 inc = btodb(size); 368 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 369 if (i != 0) { 370 if ((bp->b_npages * PAGE_SIZE) + 371 round_page(size) > vp->v_mount->mnt_iosize_max) { 372 break; 373 } 374 375 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT); 376 377 /* Don't wait around for locked bufs. */ 378 if (tbp == NULL) 379 break; 380 381 /* 382 * Stop scanning if the buffer is fully valid 383 * (marked B_CACHE), or locked (may be doing a 384 * background write), or if the buffer is not 385 * VMIO backed. The clustering code can only deal 386 * with VMIO-backed buffers. 387 */ 388 VI_LOCK(vp); 389 if ((tbp->b_vflags & BV_BKGRDINPROG) || 390 (tbp->b_flags & B_CACHE) || 391 (tbp->b_flags & B_VMIO) == 0) { 392 VI_UNLOCK(vp); 393 bqrelse(tbp); 394 break; 395 } 396 VI_UNLOCK(vp); 397 398 /* 399 * The buffer must be completely invalid in order to 400 * take part in the cluster. If it is partially valid 401 * then we stop. 402 */ 403 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 404 for (j = 0;j < tbp->b_npages; j++) { 405 VM_OBJECT_LOCK_ASSERT(tbp->b_pages[j]->object, 406 MA_OWNED); 407 if (tbp->b_pages[j]->valid) 408 break; 409 } 410 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 411 if (j != tbp->b_npages) { 412 bqrelse(tbp); 413 break; 414 } 415 416 /* 417 * Set a read-ahead mark as appropriate 418 */ 419 if ((fbp && (i == 1)) || (i == (run - 1))) 420 tbp->b_flags |= B_RAM; 421 422 /* 423 * Set the buffer up for an async read (XXX should 424 * we do this only if we do not wind up brelse()ing?). 425 * Set the block number if it isn't set, otherwise 426 * if it is make sure it matches the block number we 427 * expect. 428 */ 429 tbp->b_flags |= B_ASYNC; 430 tbp->b_iocmd = BIO_READ; 431 if (tbp->b_blkno == tbp->b_lblkno) { 432 tbp->b_blkno = bn; 433 } else if (tbp->b_blkno != bn) { 434 brelse(tbp); 435 break; 436 } 437 } 438 /* 439 * XXX fbp from caller may not be B_ASYNC, but we are going 440 * to biodone() it in cluster_callback() anyway 441 */ 442 BUF_KERNPROC(tbp); 443 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 444 tbp, b_cluster.cluster_entry); 445 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 446 for (j = 0; j < tbp->b_npages; j += 1) { 447 vm_page_t m; 448 m = tbp->b_pages[j]; 449 vm_page_io_start(m); 450 vm_object_pip_add(m->object, 1); 451 if ((bp->b_npages == 0) || 452 (bp->b_pages[bp->b_npages-1] != m)) { 453 bp->b_pages[bp->b_npages] = m; 454 bp->b_npages++; 455 } 456 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 457 tbp->b_pages[j] = bogus_page; 458 } 459 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 460 /* 461 * XXX shouldn't this be += size for both, like in 462 * cluster_wbuild()? 463 * 464 * Don't inherit tbp->b_bufsize as it may be larger due to 465 * a non-page-aligned size. Instead just aggregate using 466 * 'size'. 467 */ 468 if (tbp->b_bcount != size) 469 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 470 if (tbp->b_bufsize != size) 471 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 472 bp->b_bcount += size; 473 bp->b_bufsize += size; 474 } 475 476 /* 477 * Fully valid pages in the cluster are already good and do not need 478 * to be re-read from disk. Replace the page with bogus_page 479 */ 480 VM_OBJECT_LOCK(bp->b_bufobj->bo_object); 481 for (j = 0; j < bp->b_npages; j++) { 482 VM_OBJECT_LOCK_ASSERT(bp->b_pages[j]->object, MA_OWNED); 483 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 484 VM_PAGE_BITS_ALL) { 485 bp->b_pages[j] = bogus_page; 486 } 487 } 488 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object); 489 if (bp->b_bufsize > bp->b_kvasize) 490 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 491 bp->b_bufsize, bp->b_kvasize); 492 bp->b_kvasize = bp->b_bufsize; 493 494 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 495 (vm_page_t *)bp->b_pages, bp->b_npages); 496 return (bp); 497 } 498 499 /* 500 * Cleanup after a clustered read or write. 501 * This is complicated by the fact that any of the buffers might have 502 * extra memory (if there were no empty buffer headers at allocbuf time) 503 * that we will need to shift around. 504 */ 505 static void 506 cluster_callback(bp) 507 struct buf *bp; 508 { 509 struct buf *nbp, *tbp; 510 int error = 0; 511 512 /* 513 * Must propogate errors to all the components. 514 */ 515 if (bp->b_ioflags & BIO_ERROR) 516 error = bp->b_error; 517 518 VM_LOCK_GIANT(); 519 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 520 VM_UNLOCK_GIANT(); 521 /* 522 * Move memory from the large cluster buffer into the component 523 * buffers and mark IO as done on these. 524 */ 525 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 526 tbp; tbp = nbp) { 527 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 528 if (error) { 529 tbp->b_ioflags |= BIO_ERROR; 530 tbp->b_error = error; 531 } else { 532 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 533 tbp->b_flags &= ~B_INVAL; 534 tbp->b_ioflags &= ~BIO_ERROR; 535 /* 536 * XXX the bdwrite()/bqrelse() issued during 537 * cluster building clears B_RELBUF (see bqrelse() 538 * comment). If direct I/O was specified, we have 539 * to restore it here to allow the buffer and VM 540 * to be freed. 541 */ 542 if (tbp->b_flags & B_DIRECT) 543 tbp->b_flags |= B_RELBUF; 544 } 545 bufdone(tbp); 546 } 547 pbrelvp(bp); 548 relpbuf(bp, &cluster_pbuf_freecnt); 549 } 550 551 /* 552 * cluster_wbuild_wb: 553 * 554 * Implement modified write build for cluster. 555 * 556 * write_behind = 0 write behind disabled 557 * write_behind = 1 write behind normal (default) 558 * write_behind = 2 write behind backed-off 559 */ 560 561 static __inline int 562 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 563 { 564 int r = 0; 565 566 switch(write_behind) { 567 case 2: 568 if (start_lbn < len) 569 break; 570 start_lbn -= len; 571 /* FALLTHROUGH */ 572 case 1: 573 r = cluster_wbuild(vp, size, start_lbn, len); 574 /* FALLTHROUGH */ 575 default: 576 /* FALLTHROUGH */ 577 break; 578 } 579 return(r); 580 } 581 582 /* 583 * Do clustered write for FFS. 584 * 585 * Three cases: 586 * 1. Write is not sequential (write asynchronously) 587 * Write is sequential: 588 * 2. beginning of cluster - begin cluster 589 * 3. middle of a cluster - add to cluster 590 * 4. end of a cluster - asynchronously write cluster 591 */ 592 void 593 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount) 594 { 595 daddr_t lbn; 596 int maxclen, cursize; 597 int lblocksize; 598 int async; 599 600 if (vp->v_type == VREG) { 601 async = vp->v_mount->mnt_flag & MNT_ASYNC; 602 lblocksize = vp->v_mount->mnt_stat.f_iosize; 603 } else { 604 async = 0; 605 lblocksize = bp->b_bufsize; 606 } 607 lbn = bp->b_lblkno; 608 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 609 610 /* Initialize vnode to beginning of file. */ 611 if (lbn == 0) 612 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 613 614 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 615 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 616 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 617 if (vp->v_clen != 0) { 618 /* 619 * Next block is not sequential. 620 * 621 * If we are not writing at end of file, the process 622 * seeked to another point in the file since its last 623 * write, or we have reached our maximum cluster size, 624 * then push the previous cluster. Otherwise try 625 * reallocating to make it sequential. 626 * 627 * Change to algorithm: only push previous cluster if 628 * it was sequential from the point of view of the 629 * seqcount heuristic, otherwise leave the buffer 630 * intact so we can potentially optimize the I/O 631 * later on in the buf_daemon or update daemon 632 * flush. 633 */ 634 cursize = vp->v_lastw - vp->v_cstart + 1; 635 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 636 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 637 if (!async && seqcount > 0) { 638 cluster_wbuild_wb(vp, lblocksize, 639 vp->v_cstart, cursize); 640 } 641 } else { 642 struct buf **bpp, **endbp; 643 struct cluster_save *buflist; 644 645 buflist = cluster_collectbufs(vp, bp); 646 endbp = &buflist->bs_children 647 [buflist->bs_nchildren - 1]; 648 if (VOP_REALLOCBLKS(vp, buflist)) { 649 /* 650 * Failed, push the previous cluster 651 * if *really* writing sequentially 652 * in the logical file (seqcount > 1), 653 * otherwise delay it in the hopes that 654 * the low level disk driver can 655 * optimize the write ordering. 656 */ 657 for (bpp = buflist->bs_children; 658 bpp < endbp; bpp++) 659 brelse(*bpp); 660 free(buflist, M_SEGMENT); 661 if (seqcount > 1) { 662 cluster_wbuild_wb(vp, 663 lblocksize, vp->v_cstart, 664 cursize); 665 } 666 } else { 667 /* 668 * Succeeded, keep building cluster. 669 */ 670 for (bpp = buflist->bs_children; 671 bpp <= endbp; bpp++) 672 bdwrite(*bpp); 673 free(buflist, M_SEGMENT); 674 vp->v_lastw = lbn; 675 vp->v_lasta = bp->b_blkno; 676 return; 677 } 678 } 679 } 680 /* 681 * Consider beginning a cluster. If at end of file, make 682 * cluster as large as possible, otherwise find size of 683 * existing cluster. 684 */ 685 if ((vp->v_type == VREG) && 686 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 687 (bp->b_blkno == bp->b_lblkno) && 688 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 689 bp->b_blkno == -1)) { 690 bawrite(bp); 691 vp->v_clen = 0; 692 vp->v_lasta = bp->b_blkno; 693 vp->v_cstart = lbn + 1; 694 vp->v_lastw = lbn; 695 return; 696 } 697 vp->v_clen = maxclen; 698 if (!async && maxclen == 0) { /* I/O not contiguous */ 699 vp->v_cstart = lbn + 1; 700 bawrite(bp); 701 } else { /* Wait for rest of cluster */ 702 vp->v_cstart = lbn; 703 bdwrite(bp); 704 } 705 } else if (lbn == vp->v_cstart + vp->v_clen) { 706 /* 707 * At end of cluster, write it out if seqcount tells us we 708 * are operating sequentially, otherwise let the buf or 709 * update daemon handle it. 710 */ 711 bdwrite(bp); 712 if (seqcount > 1) 713 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 714 vp->v_clen = 0; 715 vp->v_cstart = lbn + 1; 716 } else if (vm_page_count_severe()) { 717 /* 718 * We are low on memory, get it going NOW 719 */ 720 bawrite(bp); 721 } else { 722 /* 723 * In the middle of a cluster, so just delay the I/O for now. 724 */ 725 bdwrite(bp); 726 } 727 vp->v_lastw = lbn; 728 vp->v_lasta = bp->b_blkno; 729 } 730 731 732 /* 733 * This is an awful lot like cluster_rbuild...wish they could be combined. 734 * The last lbn argument is the current block on which I/O is being 735 * performed. Check to see that it doesn't fall in the middle of 736 * the current block (if last_bp == NULL). 737 */ 738 int 739 cluster_wbuild(vp, size, start_lbn, len) 740 struct vnode *vp; 741 long size; 742 daddr_t start_lbn; 743 int len; 744 { 745 struct buf *bp, *tbp; 746 int i, j; 747 int totalwritten = 0; 748 int dbsize = btodb(size); 749 750 while (len > 0) { 751 /* 752 * If the buffer is not delayed-write (i.e. dirty), or it 753 * is delayed-write but either locked or inval, it cannot 754 * partake in the clustered write. 755 */ 756 VI_LOCK(vp); 757 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 758 (tbp->b_vflags & BV_BKGRDINPROG)) { 759 VI_UNLOCK(vp); 760 ++start_lbn; 761 --len; 762 continue; 763 } 764 if (BUF_LOCK(tbp, 765 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, VI_MTX(vp))) { 766 ++start_lbn; 767 --len; 768 continue; 769 } 770 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 771 BUF_UNLOCK(tbp); 772 ++start_lbn; 773 --len; 774 continue; 775 } 776 bremfree(tbp); 777 tbp->b_flags &= ~B_DONE; 778 779 /* 780 * Extra memory in the buffer, punt on this buffer. 781 * XXX we could handle this in most cases, but we would 782 * have to push the extra memory down to after our max 783 * possible cluster size and then potentially pull it back 784 * up if the cluster was terminated prematurely--too much 785 * hassle. 786 */ 787 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 788 (B_CLUSTEROK | B_VMIO)) || 789 (tbp->b_bcount != tbp->b_bufsize) || 790 (tbp->b_bcount != size) || 791 (len == 1) || 792 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 793 totalwritten += tbp->b_bufsize; 794 bawrite(tbp); 795 ++start_lbn; 796 --len; 797 continue; 798 } 799 800 /* 801 * We got a pbuf to make the cluster in. 802 * so initialise it. 803 */ 804 TAILQ_INIT(&bp->b_cluster.cluster_head); 805 bp->b_bcount = 0; 806 bp->b_bufsize = 0; 807 bp->b_npages = 0; 808 if (tbp->b_wcred != NOCRED) 809 bp->b_wcred = crhold(tbp->b_wcred); 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_CLUSTER | 824 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 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 /* 835 * If the adjacent data is not even in core it 836 * can't need to be written. 837 */ 838 VI_LOCK(vp); 839 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 840 (tbp->b_vflags & BV_BKGRDINPROG)) { 841 VI_UNLOCK(vp); 842 break; 843 } 844 845 /* 846 * If it IS in core, but has different 847 * characteristics, or is locked (which 848 * means it could be undergoing a background 849 * I/O or be in a weird state), then don't 850 * cluster with it. 851 */ 852 if (BUF_LOCK(tbp, 853 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 854 VI_MTX(vp))) 855 break; 856 857 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 858 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 859 != (B_DELWRI | B_CLUSTEROK | 860 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 861 tbp->b_wcred != bp->b_wcred) { 862 BUF_UNLOCK(tbp); 863 break; 864 } 865 866 /* 867 * Check that the combined cluster 868 * would make sense with regard to pages 869 * and would not be too large 870 */ 871 if ((tbp->b_bcount != size) || 872 ((bp->b_blkno + (dbsize * i)) != 873 tbp->b_blkno) || 874 ((tbp->b_npages + bp->b_npages) > 875 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 876 BUF_UNLOCK(tbp); 877 break; 878 } 879 /* 880 * Ok, it's passed all the tests, 881 * so remove it from the free list 882 * and mark it busy. We will use it. 883 */ 884 bremfree(tbp); 885 tbp->b_flags &= ~B_DONE; 886 } /* end of code for non-first buffers only */ 887 /* check for latent dependencies to be handled */ 888 if ((LIST_FIRST(&tbp->b_dep)) != NULL) { 889 tbp->b_iocmd = BIO_WRITE; 890 buf_start(tbp); 891 } 892 /* 893 * If the IO is via the VM then we do some 894 * special VM hackery (yuck). Since the buffer's 895 * block size may not be page-aligned it is possible 896 * for a page to be shared between two buffers. We 897 * have to get rid of the duplication when building 898 * the cluster. 899 */ 900 if (tbp->b_flags & B_VMIO) { 901 vm_page_t m; 902 903 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 904 if (i != 0) { /* if not first buffer */ 905 for (j = 0; j < tbp->b_npages; j += 1) { 906 m = tbp->b_pages[j]; 907 if (m->flags & PG_BUSY) { 908 VM_OBJECT_UNLOCK( 909 tbp->b_object); 910 bqrelse(tbp); 911 goto finishcluster; 912 } 913 } 914 } 915 for (j = 0; j < tbp->b_npages; j += 1) { 916 m = tbp->b_pages[j]; 917 vm_page_io_start(m); 918 vm_object_pip_add(m->object, 1); 919 if ((bp->b_npages == 0) || 920 (bp->b_pages[bp->b_npages - 1] != m)) { 921 bp->b_pages[bp->b_npages] = m; 922 bp->b_npages++; 923 } 924 } 925 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 926 } 927 bp->b_bcount += size; 928 bp->b_bufsize += size; 929 bundirty(tbp); 930 tbp->b_flags &= ~B_DONE; 931 tbp->b_ioflags &= ~BIO_ERROR; 932 tbp->b_flags |= B_ASYNC; 933 tbp->b_iocmd = BIO_WRITE; 934 reassignbuf(tbp); /* put on clean list */ 935 bufobj_wref(tbp->b_bufobj); 936 BUF_KERNPROC(tbp); 937 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 938 tbp, b_cluster.cluster_entry); 939 } 940 finishcluster: 941 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 942 (vm_page_t *) bp->b_pages, bp->b_npages); 943 if (bp->b_bufsize > bp->b_kvasize) 944 panic( 945 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 946 bp->b_bufsize, bp->b_kvasize); 947 bp->b_kvasize = bp->b_bufsize; 948 totalwritten += bp->b_bufsize; 949 bp->b_dirtyoff = 0; 950 bp->b_dirtyend = bp->b_bufsize; 951 bawrite(bp); 952 953 len -= i; 954 } 955 return totalwritten; 956 } 957 958 /* 959 * Collect together all the buffers in a cluster. 960 * Plus add one additional buffer. 961 */ 962 static struct cluster_save * 963 cluster_collectbufs(vp, last_bp) 964 struct vnode *vp; 965 struct buf *last_bp; 966 { 967 struct cluster_save *buflist; 968 struct buf *bp; 969 daddr_t lbn; 970 int i, len; 971 972 len = vp->v_lastw - vp->v_cstart + 1; 973 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 974 M_SEGMENT, M_WAITOK); 975 buflist->bs_nchildren = 0; 976 buflist->bs_children = (struct buf **) (buflist + 1); 977 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 978 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 979 buflist->bs_children[i] = bp; 980 if (bp->b_blkno == bp->b_lblkno) 981 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 982 NULL, NULL); 983 } 984 buflist->bs_children[i] = bp = last_bp; 985 if (bp->b_blkno == bp->b_lblkno) 986 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 987 buflist->bs_nchildren = i + 1; 988 return (buflist); 989 } 990