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 69 static int write_behind = 1; 70 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 71 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 72 73 static int read_max = 8; 74 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 75 "Cluster read-ahead max block count"); 76 77 /* Page expended to mark partially backed buffers */ 78 extern vm_page_t bogus_page; 79 80 /* 81 * Number of physical bufs (pbufs) this subsystem is allowed. 82 * Manipulated by vm_pager.c 83 */ 84 extern int cluster_pbuf_freecnt; 85 86 /* 87 * Read data to a buf, including read-ahead if we find this to be beneficial. 88 * cluster_read replaces bread. 89 */ 90 int 91 cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp) 92 struct vnode *vp; 93 u_quad_t filesize; 94 daddr_t lblkno; 95 long size; 96 struct ucred *cred; 97 long totread; 98 int seqcount; 99 struct buf **bpp; 100 { 101 struct buf *bp, *rbp, *reqbp; 102 daddr_t blkno, origblkno; 103 int maxra, racluster; 104 int error, ncontig; 105 int i; 106 107 error = 0; 108 109 /* 110 * Try to limit the amount of read-ahead by a few 111 * ad-hoc parameters. This needs work!!! 112 */ 113 racluster = vp->v_mount->mnt_iosize_max / size; 114 maxra = seqcount; 115 maxra = min(read_max, maxra); 116 maxra = min(nbuf/8, maxra); 117 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 118 maxra = (filesize / size) - lblkno; 119 120 /* 121 * get the requested block 122 */ 123 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0); 124 origblkno = lblkno; 125 126 /* 127 * if it is in the cache, then check to see if the reads have been 128 * sequential. If they have, then try some read-ahead, otherwise 129 * back-off on prospective read-aheads. 130 */ 131 if (bp->b_flags & B_CACHE) { 132 if (!seqcount) { 133 return 0; 134 } else if ((bp->b_flags & B_RAM) == 0) { 135 return 0; 136 } else { 137 int s; 138 bp->b_flags &= ~B_RAM; 139 /* 140 * We do the spl here so that there is no window 141 * between the incore and the b_usecount increment 142 * below. We opt to keep the spl out of the loop 143 * for efficiency. 144 */ 145 s = splbio(); 146 VI_LOCK(vp); 147 for (i = 1; i < maxra; i++) { 148 /* 149 * Stop if the buffer does not exist or it 150 * is invalid (about to go away?) 151 */ 152 rbp = gbincore(&vp->v_bufobj, lblkno+i); 153 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 154 break; 155 156 /* 157 * Set another read-ahead mark so we know 158 * to check again. 159 */ 160 if (((i % racluster) == (racluster - 1)) || 161 (i == (maxra - 1))) 162 rbp->b_flags |= B_RAM; 163 } 164 VI_UNLOCK(vp); 165 splx(s); 166 if (i >= maxra) { 167 return 0; 168 } 169 lblkno += i; 170 } 171 reqbp = bp = NULL; 172 /* 173 * If it isn't in the cache, then get a chunk from 174 * disk if sequential, otherwise just get the block. 175 */ 176 } else { 177 off_t firstread = bp->b_offset; 178 int nblks; 179 180 KASSERT(bp->b_offset != NOOFFSET, 181 ("cluster_read: no buffer offset")); 182 183 ncontig = 0; 184 185 /* 186 * Compute the total number of blocks that we should read 187 * synchronously. 188 */ 189 if (firstread + totread > filesize) 190 totread = filesize - firstread; 191 nblks = howmany(totread, size); 192 if (nblks > racluster) 193 nblks = racluster; 194 195 /* 196 * Now compute the number of contiguous blocks. 197 */ 198 if (nblks > 1) { 199 error = VOP_BMAP(vp, lblkno, NULL, 200 &blkno, &ncontig, NULL); 201 /* 202 * If this failed to map just do the original block. 203 */ 204 if (error || blkno == -1) 205 ncontig = 0; 206 } 207 208 /* 209 * If we have contiguous data available do a cluster 210 * otherwise just read the requested block. 211 */ 212 if (ncontig) { 213 /* Account for our first block. */ 214 ncontig = min(ncontig + 1, nblks); 215 if (ncontig < nblks) 216 nblks = ncontig; 217 bp = cluster_rbuild(vp, filesize, lblkno, 218 blkno, size, nblks, bp); 219 lblkno += (bp->b_bufsize / size); 220 } else { 221 bp->b_flags |= B_RAM; 222 bp->b_iocmd = BIO_READ; 223 lblkno += 1; 224 } 225 } 226 227 /* 228 * handle the synchronous read so that it is available ASAP. 229 */ 230 if (bp) { 231 if ((bp->b_flags & B_CLUSTER) == 0) { 232 vfs_busy_pages(bp, 0); 233 } 234 bp->b_flags &= ~B_INVAL; 235 bp->b_ioflags &= ~BIO_ERROR; 236 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 237 BUF_KERNPROC(bp); 238 bp->b_iooffset = dbtob(bp->b_blkno); 239 bstrategy(bp); 240 curproc->p_stats->p_ru.ru_inblock++; 241 } 242 243 /* 244 * If we have been doing sequential I/O, then do some read-ahead. 245 */ 246 while (lblkno < (origblkno + maxra)) { 247 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 248 if (error) 249 break; 250 251 if (blkno == -1) 252 break; 253 254 /* 255 * We could throttle ncontig here by maxra but we might as 256 * well read the data if it is contiguous. We're throttled 257 * by racluster anyway. 258 */ 259 if (ncontig) { 260 ncontig = min(ncontig + 1, racluster); 261 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 262 size, ncontig, NULL); 263 lblkno += (rbp->b_bufsize / size); 264 if (rbp->b_flags & B_DELWRI) { 265 bqrelse(rbp); 266 continue; 267 } 268 } else { 269 rbp = getblk(vp, lblkno, size, 0, 0, 0); 270 lblkno += 1; 271 if (rbp->b_flags & B_DELWRI) { 272 bqrelse(rbp); 273 continue; 274 } 275 rbp->b_flags |= B_ASYNC | B_RAM; 276 rbp->b_iocmd = BIO_READ; 277 rbp->b_blkno = blkno; 278 } 279 if (rbp->b_flags & B_CACHE) { 280 rbp->b_flags &= ~B_ASYNC; 281 bqrelse(rbp); 282 continue; 283 } 284 if ((rbp->b_flags & B_CLUSTER) == 0) { 285 vfs_busy_pages(rbp, 0); 286 } 287 rbp->b_flags &= ~B_INVAL; 288 rbp->b_ioflags &= ~BIO_ERROR; 289 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 290 BUF_KERNPROC(rbp); 291 rbp->b_iooffset = dbtob(rbp->b_blkno); 292 bstrategy(rbp); 293 curproc->p_stats->p_ru.ru_inblock++; 294 } 295 296 if (reqbp) 297 return (bufwait(reqbp)); 298 else 299 return (error); 300 } 301 302 /* 303 * If blocks are contiguous on disk, use this to provide clustered 304 * read ahead. We will read as many blocks as possible sequentially 305 * and then parcel them up into logical blocks in the buffer hash table. 306 */ 307 static struct buf * 308 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 309 struct vnode *vp; 310 u_quad_t filesize; 311 daddr_t lbn; 312 daddr_t blkno; 313 long size; 314 int run; 315 struct buf *fbp; 316 { 317 struct buf *bp, *tbp; 318 daddr_t bn; 319 int i, inc, j; 320 321 GIANT_REQUIRED; 322 323 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 324 ("cluster_rbuild: size %ld != filesize %jd\n", 325 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 326 327 /* 328 * avoid a division 329 */ 330 while ((u_quad_t) size * (lbn + run) > filesize) { 331 --run; 332 } 333 334 if (fbp) { 335 tbp = fbp; 336 tbp->b_iocmd = BIO_READ; 337 } else { 338 tbp = getblk(vp, lbn, size, 0, 0, 0); 339 if (tbp->b_flags & B_CACHE) 340 return tbp; 341 tbp->b_flags |= B_ASYNC | B_RAM; 342 tbp->b_iocmd = BIO_READ; 343 } 344 345 tbp->b_blkno = blkno; 346 if( (tbp->b_flags & B_MALLOC) || 347 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 348 return tbp; 349 350 bp = trypbuf(&cluster_pbuf_freecnt); 351 if (bp == 0) 352 return tbp; 353 354 /* 355 * We are synthesizing a buffer out of vm_page_t's, but 356 * if the block size is not page aligned then the starting 357 * address may not be either. Inherit the b_data offset 358 * from the original buffer. 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 } 384 385 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT); 386 387 /* Don't wait around for locked bufs. */ 388 if (tbp == NULL) 389 break; 390 391 /* 392 * Stop scanning if the buffer is fully valid 393 * (marked B_CACHE), or locked (may be doing a 394 * background write), or if the buffer is not 395 * VMIO backed. The clustering code can only deal 396 * with VMIO-backed buffers. 397 */ 398 VI_LOCK(vp); 399 if ((tbp->b_vflags & BV_BKGRDINPROG) || 400 (tbp->b_flags & B_CACHE) || 401 (tbp->b_flags & B_VMIO) == 0) { 402 VI_UNLOCK(vp); 403 bqrelse(tbp); 404 break; 405 } 406 VI_UNLOCK(vp); 407 408 /* 409 * The buffer must be completely invalid in order to 410 * take part in the cluster. If it is partially valid 411 * then we stop. 412 */ 413 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 414 for (j = 0;j < tbp->b_npages; j++) { 415 VM_OBJECT_LOCK_ASSERT(tbp->b_pages[j]->object, 416 MA_OWNED); 417 if (tbp->b_pages[j]->valid) 418 break; 419 } 420 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 421 if (j != tbp->b_npages) { 422 bqrelse(tbp); 423 break; 424 } 425 426 /* 427 * Set a read-ahead mark as appropriate 428 */ 429 if ((fbp && (i == 1)) || (i == (run - 1))) 430 tbp->b_flags |= B_RAM; 431 432 /* 433 * Set the buffer up for an async read (XXX should 434 * we do this only if we do not wind up brelse()ing?). 435 * Set the block number if it isn't set, otherwise 436 * if it is make sure it matches the block number we 437 * expect. 438 */ 439 tbp->b_flags |= B_ASYNC; 440 tbp->b_iocmd = BIO_READ; 441 if (tbp->b_blkno == tbp->b_lblkno) { 442 tbp->b_blkno = bn; 443 } else if (tbp->b_blkno != bn) { 444 brelse(tbp); 445 break; 446 } 447 } 448 /* 449 * XXX fbp from caller may not be B_ASYNC, but we are going 450 * to biodone() it in cluster_callback() anyway 451 */ 452 BUF_KERNPROC(tbp); 453 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 454 tbp, b_cluster.cluster_entry); 455 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 456 for (j = 0; j < tbp->b_npages; j += 1) { 457 vm_page_t m; 458 m = tbp->b_pages[j]; 459 vm_page_io_start(m); 460 vm_object_pip_add(m->object, 1); 461 if ((bp->b_npages == 0) || 462 (bp->b_pages[bp->b_npages-1] != m)) { 463 bp->b_pages[bp->b_npages] = m; 464 bp->b_npages++; 465 } 466 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 467 tbp->b_pages[j] = bogus_page; 468 } 469 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 470 /* 471 * XXX shouldn't this be += size for both, like in 472 * cluster_wbuild()? 473 * 474 * Don't inherit tbp->b_bufsize as it may be larger due to 475 * a non-page-aligned size. Instead just aggregate using 476 * 'size'. 477 */ 478 if (tbp->b_bcount != size) 479 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 480 if (tbp->b_bufsize != size) 481 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 482 bp->b_bcount += size; 483 bp->b_bufsize += size; 484 } 485 486 /* 487 * Fully valid pages in the cluster are already good and do not need 488 * to be re-read from disk. Replace the page with bogus_page 489 */ 490 VM_OBJECT_LOCK(bp->b_bufobj->bo_object); 491 for (j = 0; j < bp->b_npages; j++) { 492 VM_OBJECT_LOCK_ASSERT(bp->b_pages[j]->object, MA_OWNED); 493 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 494 VM_PAGE_BITS_ALL) { 495 bp->b_pages[j] = bogus_page; 496 } 497 } 498 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object); 499 if (bp->b_bufsize > bp->b_kvasize) 500 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 501 bp->b_bufsize, bp->b_kvasize); 502 bp->b_kvasize = bp->b_bufsize; 503 504 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 505 (vm_page_t *)bp->b_pages, bp->b_npages); 506 return (bp); 507 } 508 509 /* 510 * Cleanup after a clustered read or write. 511 * This is complicated by the fact that any of the buffers might have 512 * extra memory (if there were no empty buffer headers at allocbuf time) 513 * that we will need to shift around. 514 */ 515 void 516 cluster_callback(bp) 517 struct buf *bp; 518 { 519 struct buf *nbp, *tbp; 520 int error = 0; 521 522 GIANT_REQUIRED; 523 524 /* 525 * Must propogate errors to all the components. 526 */ 527 if (bp->b_ioflags & BIO_ERROR) 528 error = bp->b_error; 529 530 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 531 /* 532 * Move memory from the large cluster buffer into the component 533 * buffers and mark IO as done on these. 534 */ 535 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 536 tbp; tbp = nbp) { 537 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 538 if (error) { 539 tbp->b_ioflags |= BIO_ERROR; 540 tbp->b_error = error; 541 } else { 542 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 543 tbp->b_flags &= ~B_INVAL; 544 tbp->b_ioflags &= ~BIO_ERROR; 545 /* 546 * XXX the bdwrite()/bqrelse() issued during 547 * cluster building clears B_RELBUF (see bqrelse() 548 * comment). If direct I/O was specified, we have 549 * to restore it here to allow the buffer and VM 550 * to be freed. 551 */ 552 if (tbp->b_flags & B_DIRECT) 553 tbp->b_flags |= B_RELBUF; 554 } 555 bufdone(tbp); 556 } 557 pbrelvp(bp); 558 relpbuf(bp, &cluster_pbuf_freecnt); 559 } 560 561 /* 562 * cluster_wbuild_wb: 563 * 564 * Implement modified write build for cluster. 565 * 566 * write_behind = 0 write behind disabled 567 * write_behind = 1 write behind normal (default) 568 * write_behind = 2 write behind backed-off 569 */ 570 571 static __inline int 572 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 573 { 574 int r = 0; 575 576 switch(write_behind) { 577 case 2: 578 if (start_lbn < len) 579 break; 580 start_lbn -= len; 581 /* FALLTHROUGH */ 582 case 1: 583 r = cluster_wbuild(vp, size, start_lbn, len); 584 /* FALLTHROUGH */ 585 default: 586 /* FALLTHROUGH */ 587 break; 588 } 589 return(r); 590 } 591 592 /* 593 * Do clustered write for FFS. 594 * 595 * Three cases: 596 * 1. Write is not sequential (write asynchronously) 597 * Write is sequential: 598 * 2. beginning of cluster - begin cluster 599 * 3. middle of a cluster - add to cluster 600 * 4. end of a cluster - asynchronously write cluster 601 */ 602 void 603 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount) 604 { 605 daddr_t lbn; 606 int maxclen, cursize; 607 int lblocksize; 608 int async; 609 610 if (vp->v_type == VREG) { 611 async = vp->v_mount->mnt_flag & MNT_ASYNC; 612 lblocksize = vp->v_mount->mnt_stat.f_iosize; 613 } else { 614 async = 0; 615 lblocksize = bp->b_bufsize; 616 } 617 lbn = bp->b_lblkno; 618 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 619 620 /* Initialize vnode to beginning of file. */ 621 if (lbn == 0) 622 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 623 624 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 625 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 626 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 627 if (vp->v_clen != 0) { 628 /* 629 * Next block is not sequential. 630 * 631 * If we are not writing at end of file, the process 632 * seeked to another point in the file since its last 633 * write, or we have reached our maximum cluster size, 634 * then push the previous cluster. Otherwise try 635 * reallocating to make it sequential. 636 * 637 * Change to algorithm: only push previous cluster if 638 * it was sequential from the point of view of the 639 * seqcount heuristic, otherwise leave the buffer 640 * intact so we can potentially optimize the I/O 641 * later on in the buf_daemon or update daemon 642 * flush. 643 */ 644 cursize = vp->v_lastw - vp->v_cstart + 1; 645 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 646 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 647 if (!async && seqcount > 0) { 648 cluster_wbuild_wb(vp, lblocksize, 649 vp->v_cstart, cursize); 650 } 651 } else { 652 struct buf **bpp, **endbp; 653 struct cluster_save *buflist; 654 655 buflist = cluster_collectbufs(vp, bp); 656 endbp = &buflist->bs_children 657 [buflist->bs_nchildren - 1]; 658 if (VOP_REALLOCBLKS(vp, buflist)) { 659 /* 660 * Failed, push the previous cluster 661 * if *really* writing sequentially 662 * in the logical file (seqcount > 1), 663 * otherwise delay it in the hopes that 664 * the low level disk driver can 665 * optimize the write ordering. 666 */ 667 for (bpp = buflist->bs_children; 668 bpp < endbp; bpp++) 669 brelse(*bpp); 670 free(buflist, M_SEGMENT); 671 if (seqcount > 1) { 672 cluster_wbuild_wb(vp, 673 lblocksize, vp->v_cstart, 674 cursize); 675 } 676 } else { 677 /* 678 * Succeeded, keep building cluster. 679 */ 680 for (bpp = buflist->bs_children; 681 bpp <= endbp; bpp++) 682 bdwrite(*bpp); 683 free(buflist, M_SEGMENT); 684 vp->v_lastw = lbn; 685 vp->v_lasta = bp->b_blkno; 686 return; 687 } 688 } 689 } 690 /* 691 * Consider beginning a cluster. If at end of file, make 692 * cluster as large as possible, otherwise find size of 693 * existing cluster. 694 */ 695 if ((vp->v_type == VREG) && 696 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 697 (bp->b_blkno == bp->b_lblkno) && 698 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 699 bp->b_blkno == -1)) { 700 bawrite(bp); 701 vp->v_clen = 0; 702 vp->v_lasta = bp->b_blkno; 703 vp->v_cstart = lbn + 1; 704 vp->v_lastw = lbn; 705 return; 706 } 707 vp->v_clen = maxclen; 708 if (!async && maxclen == 0) { /* I/O not contiguous */ 709 vp->v_cstart = lbn + 1; 710 bawrite(bp); 711 } else { /* Wait for rest of cluster */ 712 vp->v_cstart = lbn; 713 bdwrite(bp); 714 } 715 } else if (lbn == vp->v_cstart + vp->v_clen) { 716 /* 717 * At end of cluster, write it out if seqcount tells us we 718 * are operating sequentially, otherwise let the buf or 719 * update daemon handle it. 720 */ 721 bdwrite(bp); 722 if (seqcount > 1) 723 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 724 vp->v_clen = 0; 725 vp->v_cstart = lbn + 1; 726 } else if (vm_page_count_severe()) { 727 /* 728 * We are low on memory, get it going NOW 729 */ 730 bawrite(bp); 731 } else { 732 /* 733 * In the middle of a cluster, so just delay the I/O for now. 734 */ 735 bdwrite(bp); 736 } 737 vp->v_lastw = lbn; 738 vp->v_lasta = bp->b_blkno; 739 } 740 741 742 /* 743 * This is an awful lot like cluster_rbuild...wish they could be combined. 744 * The last lbn argument is the current block on which I/O is being 745 * performed. Check to see that it doesn't fall in the middle of 746 * the current block (if last_bp == NULL). 747 */ 748 int 749 cluster_wbuild(vp, size, start_lbn, len) 750 struct vnode *vp; 751 long size; 752 daddr_t start_lbn; 753 int len; 754 { 755 struct buf *bp, *tbp; 756 int i, j, s; 757 int totalwritten = 0; 758 int dbsize = btodb(size); 759 760 GIANT_REQUIRED; 761 762 while (len > 0) { 763 s = splbio(); 764 /* 765 * If the buffer is not delayed-write (i.e. dirty), or it 766 * is delayed-write but either locked or inval, it cannot 767 * partake in the clustered write. 768 */ 769 VI_LOCK(vp); 770 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 771 (tbp->b_vflags & BV_BKGRDINPROG)) { 772 VI_UNLOCK(vp); 773 ++start_lbn; 774 --len; 775 splx(s); 776 continue; 777 } 778 if (BUF_LOCK(tbp, 779 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, VI_MTX(vp))) { 780 ++start_lbn; 781 --len; 782 splx(s); 783 continue; 784 } 785 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 786 BUF_UNLOCK(tbp); 787 ++start_lbn; 788 --len; 789 splx(s); 790 continue; 791 } 792 bremfree(tbp); 793 tbp->b_flags &= ~B_DONE; 794 splx(s); 795 796 /* 797 * Extra memory in the buffer, punt on this buffer. 798 * XXX we could handle this in most cases, but we would 799 * have to push the extra memory down to after our max 800 * possible cluster size and then potentially pull it back 801 * up if the cluster was terminated prematurely--too much 802 * hassle. 803 */ 804 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 805 (B_CLUSTEROK | B_VMIO)) || 806 (tbp->b_bcount != tbp->b_bufsize) || 807 (tbp->b_bcount != size) || 808 (len == 1) || 809 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 810 totalwritten += tbp->b_bufsize; 811 bawrite(tbp); 812 ++start_lbn; 813 --len; 814 continue; 815 } 816 817 /* 818 * We got a pbuf to make the cluster in. 819 * so initialise it. 820 */ 821 TAILQ_INIT(&bp->b_cluster.cluster_head); 822 bp->b_bcount = 0; 823 bp->b_bufsize = 0; 824 bp->b_npages = 0; 825 if (tbp->b_wcred != NOCRED) 826 bp->b_wcred = crhold(tbp->b_wcred); 827 828 bp->b_blkno = tbp->b_blkno; 829 bp->b_lblkno = tbp->b_lblkno; 830 bp->b_offset = tbp->b_offset; 831 832 /* 833 * We are synthesizing a buffer out of vm_page_t's, but 834 * if the block size is not page aligned then the starting 835 * address may not be either. Inherit the b_data offset 836 * from the original buffer. 837 */ 838 bp->b_data = (char *)((vm_offset_t)bp->b_data | 839 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 840 bp->b_flags |= B_CLUSTER | 841 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 842 bp->b_iodone = cluster_callback; 843 pbgetvp(vp, bp); 844 /* 845 * From this location in the file, scan forward to see 846 * if there are buffers with adjacent data that need to 847 * be written as well. 848 */ 849 for (i = 0; i < len; ++i, ++start_lbn) { 850 if (i != 0) { /* If not the first buffer */ 851 s = splbio(); 852 /* 853 * If the adjacent data is not even in core it 854 * can't need to be written. 855 */ 856 VI_LOCK(vp); 857 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 858 (tbp->b_vflags & BV_BKGRDINPROG)) { 859 VI_UNLOCK(vp); 860 splx(s); 861 break; 862 } 863 864 /* 865 * If it IS in core, but has different 866 * characteristics, or is locked (which 867 * means it could be undergoing a background 868 * I/O or be in a weird state), then don't 869 * cluster with it. 870 */ 871 if (BUF_LOCK(tbp, 872 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 873 VI_MTX(vp))) { 874 splx(s); 875 break; 876 } 877 878 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 879 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 880 != (B_DELWRI | B_CLUSTEROK | 881 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 882 tbp->b_wcred != bp->b_wcred) { 883 BUF_UNLOCK(tbp); 884 splx(s); 885 break; 886 } 887 888 /* 889 * Check that the combined cluster 890 * would make sense with regard to pages 891 * and would not be too large 892 */ 893 if ((tbp->b_bcount != size) || 894 ((bp->b_blkno + (dbsize * i)) != 895 tbp->b_blkno) || 896 ((tbp->b_npages + bp->b_npages) > 897 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 898 BUF_UNLOCK(tbp); 899 splx(s); 900 break; 901 } 902 /* 903 * Ok, it's passed all the tests, 904 * so remove it from the free list 905 * and mark it busy. We will use it. 906 */ 907 bremfree(tbp); 908 tbp->b_flags &= ~B_DONE; 909 splx(s); 910 } /* end of code for non-first buffers only */ 911 /* check for latent dependencies to be handled */ 912 if ((LIST_FIRST(&tbp->b_dep)) != NULL) { 913 tbp->b_iocmd = BIO_WRITE; 914 buf_start(tbp); 915 } 916 /* 917 * If the IO is via the VM then we do some 918 * special VM hackery (yuck). Since the buffer's 919 * block size may not be page-aligned it is possible 920 * for a page to be shared between two buffers. We 921 * have to get rid of the duplication when building 922 * the cluster. 923 */ 924 if (tbp->b_flags & B_VMIO) { 925 vm_page_t m; 926 927 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 928 if (i != 0) { /* if not first buffer */ 929 for (j = 0; j < tbp->b_npages; j += 1) { 930 m = tbp->b_pages[j]; 931 if (m->flags & PG_BUSY) { 932 VM_OBJECT_UNLOCK( 933 tbp->b_object); 934 bqrelse(tbp); 935 goto finishcluster; 936 } 937 } 938 } 939 for (j = 0; j < tbp->b_npages; j += 1) { 940 m = tbp->b_pages[j]; 941 vm_page_io_start(m); 942 vm_object_pip_add(m->object, 1); 943 if ((bp->b_npages == 0) || 944 (bp->b_pages[bp->b_npages - 1] != m)) { 945 bp->b_pages[bp->b_npages] = m; 946 bp->b_npages++; 947 } 948 } 949 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 950 } 951 bp->b_bcount += size; 952 bp->b_bufsize += size; 953 954 s = splbio(); 955 bundirty(tbp); 956 tbp->b_flags &= ~B_DONE; 957 tbp->b_ioflags &= ~BIO_ERROR; 958 tbp->b_flags |= B_ASYNC; 959 tbp->b_iocmd = BIO_WRITE; 960 reassignbuf(tbp); /* put on clean list */ 961 bufobj_wref(tbp->b_bufobj); 962 splx(s); 963 BUF_KERNPROC(tbp); 964 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 965 tbp, b_cluster.cluster_entry); 966 } 967 finishcluster: 968 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 969 (vm_page_t *) bp->b_pages, bp->b_npages); 970 if (bp->b_bufsize > bp->b_kvasize) 971 panic( 972 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 973 bp->b_bufsize, bp->b_kvasize); 974 bp->b_kvasize = bp->b_bufsize; 975 totalwritten += bp->b_bufsize; 976 bp->b_dirtyoff = 0; 977 bp->b_dirtyend = bp->b_bufsize; 978 bawrite(bp); 979 980 len -= i; 981 } 982 return totalwritten; 983 } 984 985 /* 986 * Collect together all the buffers in a cluster. 987 * Plus add one additional buffer. 988 */ 989 static struct cluster_save * 990 cluster_collectbufs(vp, last_bp) 991 struct vnode *vp; 992 struct buf *last_bp; 993 { 994 struct cluster_save *buflist; 995 struct buf *bp; 996 daddr_t lbn; 997 int i, len; 998 999 len = vp->v_lastw - vp->v_cstart + 1; 1000 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 1001 M_SEGMENT, M_WAITOK); 1002 buflist->bs_nchildren = 0; 1003 buflist->bs_children = (struct buf **) (buflist + 1); 1004 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 1005 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 1006 buflist->bs_children[i] = bp; 1007 if (bp->b_blkno == bp->b_lblkno) 1008 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 1009 NULL, NULL); 1010 } 1011 buflist->bs_children[i] = bp = last_bp; 1012 if (bp->b_blkno == bp->b_lblkno) 1013 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1014 buflist->bs_nchildren = i + 1; 1015 return (buflist); 1016 } 1017