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 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 519 /* 520 * Move memory from the large cluster buffer into the component 521 * buffers and mark IO as done on these. 522 */ 523 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 524 tbp; tbp = nbp) { 525 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 526 if (error) { 527 tbp->b_ioflags |= BIO_ERROR; 528 tbp->b_error = error; 529 } else { 530 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 531 tbp->b_flags &= ~B_INVAL; 532 tbp->b_ioflags &= ~BIO_ERROR; 533 /* 534 * XXX the bdwrite()/bqrelse() issued during 535 * cluster building clears B_RELBUF (see bqrelse() 536 * comment). If direct I/O was specified, we have 537 * to restore it here to allow the buffer and VM 538 * to be freed. 539 */ 540 if (tbp->b_flags & B_DIRECT) 541 tbp->b_flags |= B_RELBUF; 542 } 543 bufdone(tbp); 544 } 545 pbrelvp(bp); 546 relpbuf(bp, &cluster_pbuf_freecnt); 547 } 548 549 /* 550 * cluster_wbuild_wb: 551 * 552 * Implement modified write build for cluster. 553 * 554 * write_behind = 0 write behind disabled 555 * write_behind = 1 write behind normal (default) 556 * write_behind = 2 write behind backed-off 557 */ 558 559 static __inline int 560 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 561 { 562 int r = 0; 563 564 switch(write_behind) { 565 case 2: 566 if (start_lbn < len) 567 break; 568 start_lbn -= len; 569 /* FALLTHROUGH */ 570 case 1: 571 r = cluster_wbuild(vp, size, start_lbn, len); 572 /* FALLTHROUGH */ 573 default: 574 /* FALLTHROUGH */ 575 break; 576 } 577 return(r); 578 } 579 580 /* 581 * Do clustered write for FFS. 582 * 583 * Three cases: 584 * 1. Write is not sequential (write asynchronously) 585 * Write is sequential: 586 * 2. beginning of cluster - begin cluster 587 * 3. middle of a cluster - add to cluster 588 * 4. end of a cluster - asynchronously write cluster 589 */ 590 void 591 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount) 592 { 593 daddr_t lbn; 594 int maxclen, cursize; 595 int lblocksize; 596 int async; 597 598 if (vp->v_type == VREG) { 599 async = vp->v_mount->mnt_flag & MNT_ASYNC; 600 lblocksize = vp->v_mount->mnt_stat.f_iosize; 601 } else { 602 async = 0; 603 lblocksize = bp->b_bufsize; 604 } 605 lbn = bp->b_lblkno; 606 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 607 608 /* Initialize vnode to beginning of file. */ 609 if (lbn == 0) 610 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 611 612 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 613 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 614 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 615 if (vp->v_clen != 0) { 616 /* 617 * Next block is not sequential. 618 * 619 * If we are not writing at end of file, the process 620 * seeked to another point in the file since its last 621 * write, or we have reached our maximum cluster size, 622 * then push the previous cluster. Otherwise try 623 * reallocating to make it sequential. 624 * 625 * Change to algorithm: only push previous cluster if 626 * it was sequential from the point of view of the 627 * seqcount heuristic, otherwise leave the buffer 628 * intact so we can potentially optimize the I/O 629 * later on in the buf_daemon or update daemon 630 * flush. 631 */ 632 cursize = vp->v_lastw - vp->v_cstart + 1; 633 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 634 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 635 if (!async && seqcount > 0) { 636 cluster_wbuild_wb(vp, lblocksize, 637 vp->v_cstart, cursize); 638 } 639 } else { 640 struct buf **bpp, **endbp; 641 struct cluster_save *buflist; 642 643 buflist = cluster_collectbufs(vp, bp); 644 endbp = &buflist->bs_children 645 [buflist->bs_nchildren - 1]; 646 if (VOP_REALLOCBLKS(vp, buflist)) { 647 /* 648 * Failed, push the previous cluster 649 * if *really* writing sequentially 650 * in the logical file (seqcount > 1), 651 * otherwise delay it in the hopes that 652 * the low level disk driver can 653 * optimize the write ordering. 654 */ 655 for (bpp = buflist->bs_children; 656 bpp < endbp; bpp++) 657 brelse(*bpp); 658 free(buflist, M_SEGMENT); 659 if (seqcount > 1) { 660 cluster_wbuild_wb(vp, 661 lblocksize, vp->v_cstart, 662 cursize); 663 } 664 } else { 665 /* 666 * Succeeded, keep building cluster. 667 */ 668 for (bpp = buflist->bs_children; 669 bpp <= endbp; bpp++) 670 bdwrite(*bpp); 671 free(buflist, M_SEGMENT); 672 vp->v_lastw = lbn; 673 vp->v_lasta = bp->b_blkno; 674 return; 675 } 676 } 677 } 678 /* 679 * Consider beginning a cluster. If at end of file, make 680 * cluster as large as possible, otherwise find size of 681 * existing cluster. 682 */ 683 if ((vp->v_type == VREG) && 684 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 685 (bp->b_blkno == bp->b_lblkno) && 686 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 687 bp->b_blkno == -1)) { 688 bawrite(bp); 689 vp->v_clen = 0; 690 vp->v_lasta = bp->b_blkno; 691 vp->v_cstart = lbn + 1; 692 vp->v_lastw = lbn; 693 return; 694 } 695 vp->v_clen = maxclen; 696 if (!async && maxclen == 0) { /* I/O not contiguous */ 697 vp->v_cstart = lbn + 1; 698 bawrite(bp); 699 } else { /* Wait for rest of cluster */ 700 vp->v_cstart = lbn; 701 bdwrite(bp); 702 } 703 } else if (lbn == vp->v_cstart + vp->v_clen) { 704 /* 705 * At end of cluster, write it out if seqcount tells us we 706 * are operating sequentially, otherwise let the buf or 707 * update daemon handle it. 708 */ 709 bdwrite(bp); 710 if (seqcount > 1) 711 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 712 vp->v_clen = 0; 713 vp->v_cstart = lbn + 1; 714 } else if (vm_page_count_severe()) { 715 /* 716 * We are low on memory, get it going NOW 717 */ 718 bawrite(bp); 719 } else { 720 /* 721 * In the middle of a cluster, so just delay the I/O for now. 722 */ 723 bdwrite(bp); 724 } 725 vp->v_lastw = lbn; 726 vp->v_lasta = bp->b_blkno; 727 } 728 729 730 /* 731 * This is an awful lot like cluster_rbuild...wish they could be combined. 732 * The last lbn argument is the current block on which I/O is being 733 * performed. Check to see that it doesn't fall in the middle of 734 * the current block (if last_bp == NULL). 735 */ 736 int 737 cluster_wbuild(vp, size, start_lbn, len) 738 struct vnode *vp; 739 long size; 740 daddr_t start_lbn; 741 int len; 742 { 743 struct buf *bp, *tbp; 744 int i, j; 745 int totalwritten = 0; 746 int dbsize = btodb(size); 747 748 while (len > 0) { 749 /* 750 * If the buffer is not delayed-write (i.e. dirty), or it 751 * is delayed-write but either locked or inval, it cannot 752 * partake in the clustered write. 753 */ 754 VI_LOCK(vp); 755 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 756 (tbp->b_vflags & BV_BKGRDINPROG)) { 757 VI_UNLOCK(vp); 758 ++start_lbn; 759 --len; 760 continue; 761 } 762 if (BUF_LOCK(tbp, 763 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, VI_MTX(vp))) { 764 ++start_lbn; 765 --len; 766 continue; 767 } 768 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 769 BUF_UNLOCK(tbp); 770 ++start_lbn; 771 --len; 772 continue; 773 } 774 bremfree(tbp); 775 tbp->b_flags &= ~B_DONE; 776 777 /* 778 * Extra memory in the buffer, punt on this buffer. 779 * XXX we could handle this in most cases, but we would 780 * have to push the extra memory down to after our max 781 * possible cluster size and then potentially pull it back 782 * up if the cluster was terminated prematurely--too much 783 * hassle. 784 */ 785 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 786 (B_CLUSTEROK | B_VMIO)) || 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 = crhold(tbp->b_wcred); 808 809 bp->b_blkno = tbp->b_blkno; 810 bp->b_lblkno = tbp->b_lblkno; 811 bp->b_offset = tbp->b_offset; 812 813 /* 814 * We are synthesizing a buffer out of vm_page_t's, but 815 * if the block size is not page aligned then the starting 816 * address may not be either. Inherit the b_data offset 817 * from the original buffer. 818 */ 819 bp->b_data = (char *)((vm_offset_t)bp->b_data | 820 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 821 bp->b_flags |= B_CLUSTER | 822 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 823 bp->b_iodone = cluster_callback; 824 pbgetvp(vp, bp); 825 /* 826 * From this location in the file, scan forward to see 827 * if there are buffers with adjacent data that need to 828 * be written as well. 829 */ 830 for (i = 0; i < len; ++i, ++start_lbn) { 831 if (i != 0) { /* If not the first buffer */ 832 /* 833 * If the adjacent data is not even in core it 834 * can't need to be written. 835 */ 836 VI_LOCK(vp); 837 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 838 (tbp->b_vflags & BV_BKGRDINPROG)) { 839 VI_UNLOCK(vp); 840 break; 841 } 842 843 /* 844 * If it IS in core, but has different 845 * characteristics, or is locked (which 846 * means it could be undergoing a background 847 * I/O or be in a weird state), then don't 848 * cluster with it. 849 */ 850 if (BUF_LOCK(tbp, 851 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 852 VI_MTX(vp))) 853 break; 854 855 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 856 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 857 != (B_DELWRI | B_CLUSTEROK | 858 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 859 tbp->b_wcred != bp->b_wcred) { 860 BUF_UNLOCK(tbp); 861 break; 862 } 863 864 /* 865 * Check that the combined cluster 866 * would make sense with regard to pages 867 * and would not be too large 868 */ 869 if ((tbp->b_bcount != size) || 870 ((bp->b_blkno + (dbsize * i)) != 871 tbp->b_blkno) || 872 ((tbp->b_npages + bp->b_npages) > 873 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 874 BUF_UNLOCK(tbp); 875 break; 876 } 877 /* 878 * Ok, it's passed all the tests, 879 * so remove it from the free list 880 * and mark it busy. We will use it. 881 */ 882 bremfree(tbp); 883 tbp->b_flags &= ~B_DONE; 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 tbp->b_iocmd = BIO_WRITE; 888 buf_start(tbp); 889 } 890 /* 891 * If the IO is via the VM then we do some 892 * special VM hackery (yuck). Since the buffer's 893 * block size may not be page-aligned it is possible 894 * for a page to be shared between two buffers. We 895 * have to get rid of the duplication when building 896 * the cluster. 897 */ 898 if (tbp->b_flags & B_VMIO) { 899 vm_page_t m; 900 901 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 902 if (i != 0) { /* if not first buffer */ 903 for (j = 0; j < tbp->b_npages; j += 1) { 904 m = tbp->b_pages[j]; 905 if (m->flags & PG_BUSY) { 906 VM_OBJECT_UNLOCK( 907 tbp->b_object); 908 bqrelse(tbp); 909 goto finishcluster; 910 } 911 } 912 } 913 for (j = 0; j < tbp->b_npages; j += 1) { 914 m = tbp->b_pages[j]; 915 vm_page_io_start(m); 916 vm_object_pip_add(m->object, 1); 917 if ((bp->b_npages == 0) || 918 (bp->b_pages[bp->b_npages - 1] != m)) { 919 bp->b_pages[bp->b_npages] = m; 920 bp->b_npages++; 921 } 922 } 923 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 924 } 925 bp->b_bcount += size; 926 bp->b_bufsize += size; 927 bundirty(tbp); 928 tbp->b_flags &= ~B_DONE; 929 tbp->b_ioflags &= ~BIO_ERROR; 930 tbp->b_flags |= B_ASYNC; 931 tbp->b_iocmd = BIO_WRITE; 932 reassignbuf(tbp); /* put on clean list */ 933 bufobj_wref(tbp->b_bufobj); 934 BUF_KERNPROC(tbp); 935 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 936 tbp, b_cluster.cluster_entry); 937 } 938 finishcluster: 939 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 940 (vm_page_t *) bp->b_pages, bp->b_npages); 941 if (bp->b_bufsize > bp->b_kvasize) 942 panic( 943 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 944 bp->b_bufsize, bp->b_kvasize); 945 bp->b_kvasize = bp->b_bufsize; 946 totalwritten += bp->b_bufsize; 947 bp->b_dirtyoff = 0; 948 bp->b_dirtyend = bp->b_bufsize; 949 bawrite(bp); 950 951 len -= i; 952 } 953 return totalwritten; 954 } 955 956 /* 957 * Collect together all the buffers in a cluster. 958 * Plus add one additional buffer. 959 */ 960 static struct cluster_save * 961 cluster_collectbufs(vp, last_bp) 962 struct vnode *vp; 963 struct buf *last_bp; 964 { 965 struct cluster_save *buflist; 966 struct buf *bp; 967 daddr_t lbn; 968 int i, len; 969 970 len = vp->v_lastw - vp->v_cstart + 1; 971 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 972 M_SEGMENT, M_WAITOK); 973 buflist->bs_nchildren = 0; 974 buflist->bs_children = (struct buf **) (buflist + 1); 975 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 976 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 977 buflist->bs_children[i] = bp; 978 if (bp->b_blkno == bp->b_lblkno) 979 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 980 NULL, NULL); 981 } 982 buflist->bs_children[i] = bp = last_bp; 983 if (bp->b_blkno == bp->b_lblkno) 984 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 985 buflist->bs_nchildren = i + 1; 986 return (buflist); 987 } 988