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/rwlock.h> 50 #include <sys/vmmeter.h> 51 #include <vm/vm.h> 52 #include <vm/vm_object.h> 53 #include <vm/vm_page.h> 54 #include <sys/sysctl.h> 55 56 #if defined(CLUSTERDEBUG) 57 static int rcluster= 0; 58 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, 59 "Debug VFS clustering code"); 60 #endif 61 62 static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer"); 63 64 static struct cluster_save * 65 cluster_collectbufs(struct vnode *vp, struct buf *last_bp); 66 static struct buf * 67 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 68 daddr_t blkno, long size, int run, struct buf *fbp); 69 static void cluster_callback(struct buf *); 70 71 static int write_behind = 1; 72 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 73 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 74 75 static int read_max = 64; 76 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 77 "Cluster read-ahead max block count"); 78 79 /* Page expended to mark partially backed buffers */ 80 extern vm_page_t bogus_page; 81 82 /* 83 * Read data to a buf, including read-ahead if we find this to be beneficial. 84 * cluster_read replaces bread. 85 */ 86 int 87 cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, long size, 88 struct ucred *cred, long totread, int seqcount, int gbflags, 89 struct buf **bpp) 90 { 91 struct buf *bp, *rbp, *reqbp; 92 struct bufobj *bo; 93 daddr_t blkno, origblkno; 94 int maxra, racluster; 95 int error, ncontig; 96 int i; 97 98 error = 0; 99 bo = &vp->v_bufobj; 100 101 /* 102 * Try to limit the amount of read-ahead by a few 103 * ad-hoc parameters. This needs work!!! 104 */ 105 racluster = vp->v_mount->mnt_iosize_max / size; 106 maxra = seqcount; 107 maxra = min(read_max, maxra); 108 maxra = min(nbuf/8, maxra); 109 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 110 maxra = (filesize / size) - lblkno; 111 112 /* 113 * get the requested block 114 */ 115 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0); 116 origblkno = lblkno; 117 118 /* 119 * if it is in the cache, then check to see if the reads have been 120 * sequential. If they have, then try some read-ahead, otherwise 121 * back-off on prospective read-aheads. 122 */ 123 if (bp->b_flags & B_CACHE) { 124 if (!seqcount) { 125 return 0; 126 } else if ((bp->b_flags & B_RAM) == 0) { 127 return 0; 128 } else { 129 bp->b_flags &= ~B_RAM; 130 BO_LOCK(bo); 131 for (i = 1; i < maxra; i++) { 132 /* 133 * Stop if the buffer does not exist or it 134 * is invalid (about to go away?) 135 */ 136 rbp = gbincore(&vp->v_bufobj, lblkno+i); 137 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 138 break; 139 140 /* 141 * Set another read-ahead mark so we know 142 * to check again. (If we can lock the 143 * buffer without waiting) 144 */ 145 if ((((i % racluster) == (racluster - 1)) || 146 (i == (maxra - 1))) 147 && (0 == BUF_LOCK(rbp, 148 LK_EXCLUSIVE | LK_NOWAIT, NULL))) { 149 rbp->b_flags |= B_RAM; 150 BUF_UNLOCK(rbp); 151 } 152 } 153 BO_UNLOCK(bo); 154 if (i >= maxra) { 155 return 0; 156 } 157 lblkno += i; 158 } 159 reqbp = bp = NULL; 160 /* 161 * If it isn't in the cache, then get a chunk from 162 * disk if sequential, otherwise just get the block. 163 */ 164 } else { 165 off_t firstread = bp->b_offset; 166 int nblks; 167 168 KASSERT(bp->b_offset != NOOFFSET, 169 ("cluster_read: no buffer offset")); 170 171 ncontig = 0; 172 173 /* 174 * Compute the total number of blocks that we should read 175 * synchronously. 176 */ 177 if (firstread + totread > filesize) 178 totread = filesize - firstread; 179 nblks = howmany(totread, size); 180 if (nblks > racluster) 181 nblks = racluster; 182 183 /* 184 * Now compute the number of contiguous blocks. 185 */ 186 if (nblks > 1) { 187 error = VOP_BMAP(vp, lblkno, NULL, 188 &blkno, &ncontig, NULL); 189 /* 190 * If this failed to map just do the original block. 191 */ 192 if (error || blkno == -1) 193 ncontig = 0; 194 } 195 196 /* 197 * If we have contiguous data available do a cluster 198 * otherwise just read the requested block. 199 */ 200 if (ncontig) { 201 /* Account for our first block. */ 202 ncontig = min(ncontig + 1, nblks); 203 if (ncontig < nblks) 204 nblks = ncontig; 205 bp = cluster_rbuild(vp, filesize, lblkno, 206 blkno, size, nblks, bp); 207 lblkno += (bp->b_bufsize / size); 208 } else { 209 bp->b_flags |= B_RAM; 210 bp->b_iocmd = BIO_READ; 211 lblkno += 1; 212 } 213 } 214 215 /* 216 * handle the synchronous read so that it is available ASAP. 217 */ 218 if (bp) { 219 if ((bp->b_flags & B_CLUSTER) == 0) { 220 vfs_busy_pages(bp, 0); 221 } 222 bp->b_flags &= ~B_INVAL; 223 bp->b_ioflags &= ~BIO_ERROR; 224 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 225 BUF_KERNPROC(bp); 226 bp->b_iooffset = dbtob(bp->b_blkno); 227 bstrategy(bp); 228 curthread->td_ru.ru_inblock++; 229 } 230 231 /* 232 * If we have been doing sequential I/O, then do some read-ahead. 233 */ 234 while (lblkno < (origblkno + maxra)) { 235 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 236 if (error) 237 break; 238 239 if (blkno == -1) 240 break; 241 242 /* 243 * We could throttle ncontig here by maxra but we might as 244 * well read the data if it is contiguous. We're throttled 245 * by racluster anyway. 246 */ 247 if (ncontig) { 248 ncontig = min(ncontig + 1, racluster); 249 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 250 size, ncontig, NULL); 251 lblkno += (rbp->b_bufsize / size); 252 if (rbp->b_flags & B_DELWRI) { 253 bqrelse(rbp); 254 continue; 255 } 256 } else { 257 rbp = getblk(vp, lblkno, size, 0, 0, 0); 258 lblkno += 1; 259 if (rbp->b_flags & B_DELWRI) { 260 bqrelse(rbp); 261 continue; 262 } 263 rbp->b_flags |= B_ASYNC | B_RAM; 264 rbp->b_iocmd = BIO_READ; 265 rbp->b_blkno = blkno; 266 } 267 if (rbp->b_flags & B_CACHE) { 268 rbp->b_flags &= ~B_ASYNC; 269 bqrelse(rbp); 270 continue; 271 } 272 if ((rbp->b_flags & B_CLUSTER) == 0) { 273 vfs_busy_pages(rbp, 0); 274 } 275 rbp->b_flags &= ~B_INVAL; 276 rbp->b_ioflags &= ~BIO_ERROR; 277 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 278 BUF_KERNPROC(rbp); 279 rbp->b_iooffset = dbtob(rbp->b_blkno); 280 bstrategy(rbp); 281 curthread->td_ru.ru_inblock++; 282 } 283 284 if (reqbp) 285 return (bufwait(reqbp)); 286 else 287 return (error); 288 } 289 290 /* 291 * If blocks are contiguous on disk, use this to provide clustered 292 * read ahead. We will read as many blocks as possible sequentially 293 * and then parcel them up into logical blocks in the buffer hash table. 294 */ 295 static struct buf * 296 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 297 struct vnode *vp; 298 u_quad_t filesize; 299 daddr_t lbn; 300 daddr_t blkno; 301 long size; 302 int run; 303 struct buf *fbp; 304 { 305 struct bufobj *bo; 306 struct buf *bp, *tbp; 307 daddr_t bn; 308 off_t off; 309 long tinc, tsize; 310 int i, inc, j, toff; 311 312 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 313 ("cluster_rbuild: size %ld != f_iosize %jd\n", 314 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 315 316 /* 317 * avoid a division 318 */ 319 while ((u_quad_t) size * (lbn + run) > filesize) { 320 --run; 321 } 322 323 if (fbp) { 324 tbp = fbp; 325 tbp->b_iocmd = BIO_READ; 326 } else { 327 tbp = getblk(vp, lbn, size, 0, 0, 0); 328 if (tbp->b_flags & B_CACHE) 329 return tbp; 330 tbp->b_flags |= B_ASYNC | B_RAM; 331 tbp->b_iocmd = BIO_READ; 332 } 333 tbp->b_blkno = blkno; 334 if( (tbp->b_flags & B_MALLOC) || 335 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 336 return tbp; 337 338 bp = trypbuf(&cluster_pbuf_freecnt); 339 if (bp == 0) 340 return tbp; 341 342 /* 343 * We are synthesizing a buffer out of vm_page_t's, but 344 * if the block size is not page aligned then the starting 345 * address may not be either. Inherit the b_data offset 346 * from the original buffer. 347 */ 348 bp->b_data = (char *)((vm_offset_t)bp->b_data | 349 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 350 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 351 bp->b_iocmd = BIO_READ; 352 bp->b_iodone = cluster_callback; 353 bp->b_blkno = blkno; 354 bp->b_lblkno = lbn; 355 bp->b_offset = tbp->b_offset; 356 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 357 pbgetvp(vp, bp); 358 359 TAILQ_INIT(&bp->b_cluster.cluster_head); 360 361 bp->b_bcount = 0; 362 bp->b_bufsize = 0; 363 bp->b_npages = 0; 364 365 inc = btodb(size); 366 bo = &vp->v_bufobj; 367 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 368 if (i != 0) { 369 if ((bp->b_npages * PAGE_SIZE) + 370 round_page(size) > vp->v_mount->mnt_iosize_max) { 371 break; 372 } 373 374 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT); 375 376 /* Don't wait around for locked bufs. */ 377 if (tbp == NULL) 378 break; 379 380 /* 381 * Stop scanning if the buffer is fully valid 382 * (marked B_CACHE), or locked (may be doing a 383 * background write), or if the buffer is not 384 * VMIO backed. The clustering code can only deal 385 * with VMIO-backed buffers. 386 */ 387 BO_LOCK(bo); 388 if ((tbp->b_vflags & BV_BKGRDINPROG) || 389 (tbp->b_flags & B_CACHE) || 390 (tbp->b_flags & B_VMIO) == 0) { 391 BO_UNLOCK(bo); 392 bqrelse(tbp); 393 break; 394 } 395 BO_UNLOCK(bo); 396 397 /* 398 * The buffer must be completely invalid in order to 399 * take part in the cluster. If it is partially valid 400 * then we stop. 401 */ 402 off = tbp->b_offset; 403 tsize = size; 404 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 405 for (j = 0; tsize > 0; j++) { 406 toff = off & PAGE_MASK; 407 tinc = tsize; 408 if (toff + tinc > PAGE_SIZE) 409 tinc = PAGE_SIZE - toff; 410 VM_OBJECT_ASSERT_WLOCKED(tbp->b_pages[j]->object); 411 if ((tbp->b_pages[j]->valid & 412 vm_page_bits(toff, tinc)) != 0) 413 break; 414 off += tinc; 415 tsize -= tinc; 416 } 417 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 418 if (tsize > 0) { 419 bqrelse(tbp); 420 break; 421 } 422 423 /* 424 * Set a read-ahead mark as appropriate 425 */ 426 if ((fbp && (i == 1)) || (i == (run - 1))) 427 tbp->b_flags |= B_RAM; 428 429 /* 430 * Set the buffer up for an async read (XXX should 431 * we do this only if we do not wind up brelse()ing?). 432 * Set the block number if it isn't set, otherwise 433 * if it is make sure it matches the block number we 434 * expect. 435 */ 436 tbp->b_flags |= B_ASYNC; 437 tbp->b_iocmd = BIO_READ; 438 if (tbp->b_blkno == tbp->b_lblkno) { 439 tbp->b_blkno = bn; 440 } else if (tbp->b_blkno != bn) { 441 brelse(tbp); 442 break; 443 } 444 } 445 /* 446 * XXX fbp from caller may not be B_ASYNC, but we are going 447 * to biodone() it in cluster_callback() anyway 448 */ 449 BUF_KERNPROC(tbp); 450 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 451 tbp, b_cluster.cluster_entry); 452 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 453 for (j = 0; j < tbp->b_npages; j += 1) { 454 vm_page_t m; 455 m = tbp->b_pages[j]; 456 vm_page_io_start(m); 457 vm_object_pip_add(m->object, 1); 458 if ((bp->b_npages == 0) || 459 (bp->b_pages[bp->b_npages-1] != m)) { 460 bp->b_pages[bp->b_npages] = m; 461 bp->b_npages++; 462 } 463 if (m->valid == VM_PAGE_BITS_ALL) 464 tbp->b_pages[j] = bogus_page; 465 } 466 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 467 /* 468 * Don't inherit tbp->b_bufsize as it may be larger due to 469 * a non-page-aligned size. Instead just aggregate using 470 * 'size'. 471 */ 472 if (tbp->b_bcount != size) 473 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 474 if (tbp->b_bufsize != size) 475 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 476 bp->b_bcount += size; 477 bp->b_bufsize += size; 478 } 479 480 /* 481 * Fully valid pages in the cluster are already good and do not need 482 * to be re-read from disk. Replace the page with bogus_page 483 */ 484 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 485 for (j = 0; j < bp->b_npages; j++) { 486 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[j]->object); 487 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL) 488 bp->b_pages[j] = bogus_page; 489 } 490 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 491 if (bp->b_bufsize > bp->b_kvasize) 492 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 493 bp->b_bufsize, bp->b_kvasize); 494 bp->b_kvasize = bp->b_bufsize; 495 496 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 497 (vm_page_t *)bp->b_pages, bp->b_npages); 498 return (bp); 499 } 500 501 /* 502 * Cleanup after a clustered read or write. 503 * This is complicated by the fact that any of the buffers might have 504 * extra memory (if there were no empty buffer headers at allocbuf time) 505 * that we will need to shift around. 506 */ 507 static void 508 cluster_callback(bp) 509 struct buf *bp; 510 { 511 struct buf *nbp, *tbp; 512 int error = 0; 513 514 /* 515 * Must propogate errors to all the components. 516 */ 517 if (bp->b_ioflags & BIO_ERROR) 518 error = bp->b_error; 519 520 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 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, 0); 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 int gbflags) 595 { 596 daddr_t lbn; 597 int maxclen, cursize; 598 int lblocksize; 599 int async; 600 601 if (vp->v_type == VREG) { 602 async = DOINGASYNC(vp); 603 lblocksize = vp->v_mount->mnt_stat.f_iosize; 604 } else { 605 async = 0; 606 lblocksize = bp->b_bufsize; 607 } 608 lbn = bp->b_lblkno; 609 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 610 611 /* Initialize vnode to beginning of file. */ 612 if (lbn == 0) 613 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 614 615 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 616 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 617 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 618 if (vp->v_clen != 0) { 619 /* 620 * Next block is not sequential. 621 * 622 * If we are not writing at end of file, the process 623 * seeked to another point in the file since its last 624 * write, or we have reached our maximum cluster size, 625 * then push the previous cluster. Otherwise try 626 * reallocating to make it sequential. 627 * 628 * Change to algorithm: only push previous cluster if 629 * it was sequential from the point of view of the 630 * seqcount heuristic, otherwise leave the buffer 631 * intact so we can potentially optimize the I/O 632 * later on in the buf_daemon or update daemon 633 * flush. 634 */ 635 cursize = vp->v_lastw - vp->v_cstart + 1; 636 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 637 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 638 if (!async && seqcount > 0) { 639 cluster_wbuild_wb(vp, lblocksize, 640 vp->v_cstart, cursize); 641 } 642 } else { 643 struct buf **bpp, **endbp; 644 struct cluster_save *buflist; 645 646 buflist = cluster_collectbufs(vp, bp); 647 endbp = &buflist->bs_children 648 [buflist->bs_nchildren - 1]; 649 if (VOP_REALLOCBLKS(vp, buflist)) { 650 /* 651 * Failed, push the previous cluster 652 * if *really* writing sequentially 653 * in the logical file (seqcount > 1), 654 * otherwise delay it in the hopes that 655 * the low level disk driver can 656 * optimize the write ordering. 657 */ 658 for (bpp = buflist->bs_children; 659 bpp < endbp; bpp++) 660 brelse(*bpp); 661 free(buflist, M_SEGMENT); 662 if (seqcount > 1) { 663 cluster_wbuild_wb(vp, 664 lblocksize, vp->v_cstart, 665 cursize); 666 } 667 } else { 668 /* 669 * Succeeded, keep building cluster. 670 */ 671 for (bpp = buflist->bs_children; 672 bpp <= endbp; bpp++) 673 bdwrite(*bpp); 674 free(buflist, M_SEGMENT); 675 vp->v_lastw = lbn; 676 vp->v_lasta = bp->b_blkno; 677 return; 678 } 679 } 680 } 681 /* 682 * Consider beginning a cluster. If at end of file, make 683 * cluster as large as possible, otherwise find size of 684 * existing cluster. 685 */ 686 if ((vp->v_type == VREG) && 687 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 688 (bp->b_blkno == bp->b_lblkno) && 689 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 690 bp->b_blkno == -1)) { 691 bawrite(bp); 692 vp->v_clen = 0; 693 vp->v_lasta = bp->b_blkno; 694 vp->v_cstart = lbn + 1; 695 vp->v_lastw = lbn; 696 return; 697 } 698 vp->v_clen = maxclen; 699 if (!async && maxclen == 0) { /* I/O not contiguous */ 700 vp->v_cstart = lbn + 1; 701 bawrite(bp); 702 } else { /* Wait for rest of cluster */ 703 vp->v_cstart = lbn; 704 bdwrite(bp); 705 } 706 } else if (lbn == vp->v_cstart + vp->v_clen) { 707 /* 708 * At end of cluster, write it out if seqcount tells us we 709 * are operating sequentially, otherwise let the buf or 710 * update daemon handle it. 711 */ 712 bdwrite(bp); 713 if (seqcount > 1) 714 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 715 vp->v_clen = 0; 716 vp->v_cstart = lbn + 1; 717 } else if (vm_page_count_severe()) { 718 /* 719 * We are low on memory, get it going NOW 720 */ 721 bawrite(bp); 722 } else { 723 /* 724 * In the middle of a cluster, so just delay the I/O for now. 725 */ 726 bdwrite(bp); 727 } 728 vp->v_lastw = lbn; 729 vp->v_lasta = bp->b_blkno; 730 } 731 732 733 /* 734 * This is an awful lot like cluster_rbuild...wish they could be combined. 735 * The last lbn argument is the current block on which I/O is being 736 * performed. Check to see that it doesn't fall in the middle of 737 * the current block (if last_bp == NULL). 738 */ 739 int 740 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len, 741 int gbflags) 742 { 743 struct buf *bp, *tbp; 744 struct bufobj *bo; 745 int i, j; 746 int totalwritten = 0; 747 int dbsize = btodb(size); 748 749 bo = &vp->v_bufobj; 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 BO_LOCK(bo); 757 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 758 (tbp->b_vflags & BV_BKGRDINPROG)) { 759 BO_UNLOCK(bo); 760 ++start_lbn; 761 --len; 762 continue; 763 } 764 if (BUF_LOCK(tbp, 765 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_MTX(bo))) { 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 if (tbp->b_pin_count > 0) { 777 BUF_UNLOCK(tbp); 778 ++start_lbn; 779 --len; 780 continue; 781 } 782 bremfree(tbp); 783 tbp->b_flags &= ~B_DONE; 784 785 /* 786 * Extra memory in the buffer, punt on this buffer. 787 * XXX we could handle this in most cases, but we would 788 * have to push the extra memory down to after our max 789 * possible cluster size and then potentially pull it back 790 * up if the cluster was terminated prematurely--too much 791 * hassle. 792 */ 793 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 794 (B_CLUSTEROK | B_VMIO)) || 795 (tbp->b_bcount != tbp->b_bufsize) || 796 (tbp->b_bcount != size) || 797 (len == 1) || 798 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 799 totalwritten += tbp->b_bufsize; 800 bawrite(tbp); 801 ++start_lbn; 802 --len; 803 continue; 804 } 805 806 /* 807 * We got a pbuf to make the cluster in. 808 * so initialise it. 809 */ 810 TAILQ_INIT(&bp->b_cluster.cluster_head); 811 bp->b_bcount = 0; 812 bp->b_bufsize = 0; 813 bp->b_npages = 0; 814 if (tbp->b_wcred != NOCRED) 815 bp->b_wcred = crhold(tbp->b_wcred); 816 817 bp->b_blkno = tbp->b_blkno; 818 bp->b_lblkno = tbp->b_lblkno; 819 bp->b_offset = tbp->b_offset; 820 821 /* 822 * We are synthesizing a buffer out of vm_page_t's, but 823 * if the block size is not page aligned then the starting 824 * address may not be either. Inherit the b_data offset 825 * from the original buffer. 826 */ 827 bp->b_data = (char *)((vm_offset_t)bp->b_data | 828 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 829 bp->b_flags |= B_CLUSTER | 830 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 831 bp->b_iodone = cluster_callback; 832 pbgetvp(vp, bp); 833 /* 834 * From this location in the file, scan forward to see 835 * if there are buffers with adjacent data that need to 836 * be written as well. 837 */ 838 for (i = 0; i < len; ++i, ++start_lbn) { 839 if (i != 0) { /* If not the first buffer */ 840 /* 841 * If the adjacent data is not even in core it 842 * can't need to be written. 843 */ 844 BO_LOCK(bo); 845 if ((tbp = gbincore(bo, start_lbn)) == NULL || 846 (tbp->b_vflags & BV_BKGRDINPROG)) { 847 BO_UNLOCK(bo); 848 break; 849 } 850 851 /* 852 * If it IS in core, but has different 853 * characteristics, or is locked (which 854 * means it could be undergoing a background 855 * I/O or be in a weird state), then don't 856 * cluster with it. 857 */ 858 if (BUF_LOCK(tbp, 859 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 860 BO_MTX(bo))) 861 break; 862 863 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 864 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 865 != (B_DELWRI | B_CLUSTEROK | 866 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 867 tbp->b_wcred != bp->b_wcred) { 868 BUF_UNLOCK(tbp); 869 break; 870 } 871 872 /* 873 * Check that the combined cluster 874 * would make sense with regard to pages 875 * and would not be too large 876 */ 877 if ((tbp->b_bcount != size) || 878 ((bp->b_blkno + (dbsize * i)) != 879 tbp->b_blkno) || 880 ((tbp->b_npages + bp->b_npages) > 881 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 882 BUF_UNLOCK(tbp); 883 break; 884 } 885 886 /* 887 * Do not pull in pinned buffers. 888 */ 889 if (tbp->b_pin_count > 0) { 890 BUF_UNLOCK(tbp); 891 break; 892 } 893 894 /* 895 * Ok, it's passed all the tests, 896 * so remove it from the free list 897 * and mark it busy. We will use it. 898 */ 899 bremfree(tbp); 900 tbp->b_flags &= ~B_DONE; 901 } /* end of code for non-first buffers only */ 902 /* 903 * If the IO is via the VM then we do some 904 * special VM hackery (yuck). Since the buffer's 905 * block size may not be page-aligned it is possible 906 * for a page to be shared between two buffers. We 907 * have to get rid of the duplication when building 908 * the cluster. 909 */ 910 if (tbp->b_flags & B_VMIO) { 911 vm_page_t m; 912 913 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 914 if (i != 0) { /* if not first buffer */ 915 for (j = 0; j < tbp->b_npages; j += 1) { 916 m = tbp->b_pages[j]; 917 if (m->oflags & VPO_BUSY) { 918 VM_OBJECT_WUNLOCK( 919 tbp->b_object); 920 bqrelse(tbp); 921 goto finishcluster; 922 } 923 } 924 } 925 for (j = 0; j < tbp->b_npages; j += 1) { 926 m = tbp->b_pages[j]; 927 vm_page_io_start(m); 928 vm_object_pip_add(m->object, 1); 929 if ((bp->b_npages == 0) || 930 (bp->b_pages[bp->b_npages - 1] != m)) { 931 bp->b_pages[bp->b_npages] = m; 932 bp->b_npages++; 933 } 934 } 935 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 936 } 937 bp->b_bcount += size; 938 bp->b_bufsize += size; 939 /* 940 * If any of the clustered buffers have their 941 * B_BARRIER flag set, transfer that request to 942 * the cluster. 943 */ 944 bp->b_flags |= (tbp->b_flags & B_BARRIER); 945 tbp->b_flags &= ~(B_DONE | B_BARRIER); 946 tbp->b_flags |= B_ASYNC; 947 tbp->b_ioflags &= ~BIO_ERROR; 948 tbp->b_iocmd = BIO_WRITE; 949 bundirty(tbp); 950 reassignbuf(tbp); /* put on clean list */ 951 bufobj_wref(tbp->b_bufobj); 952 BUF_KERNPROC(tbp); 953 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 954 tbp, b_cluster.cluster_entry); 955 } 956 finishcluster: 957 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 958 (vm_page_t *) bp->b_pages, bp->b_npages); 959 if (bp->b_bufsize > bp->b_kvasize) 960 panic( 961 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 962 bp->b_bufsize, bp->b_kvasize); 963 bp->b_kvasize = bp->b_bufsize; 964 totalwritten += bp->b_bufsize; 965 bp->b_dirtyoff = 0; 966 bp->b_dirtyend = bp->b_bufsize; 967 bawrite(bp); 968 969 len -= i; 970 } 971 return totalwritten; 972 } 973 974 /* 975 * Collect together all the buffers in a cluster. 976 * Plus add one additional buffer. 977 */ 978 static struct cluster_save * 979 cluster_collectbufs(vp, last_bp) 980 struct vnode *vp; 981 struct buf *last_bp; 982 { 983 struct cluster_save *buflist; 984 struct buf *bp; 985 daddr_t lbn; 986 int i, len; 987 988 len = vp->v_lastw - vp->v_cstart + 1; 989 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 990 M_SEGMENT, M_WAITOK); 991 buflist->bs_nchildren = 0; 992 buflist->bs_children = (struct buf **) (buflist + 1); 993 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 994 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 995 buflist->bs_children[i] = bp; 996 if (bp->b_blkno == bp->b_lblkno) 997 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 998 NULL, NULL); 999 } 1000 buflist->bs_children[i] = bp = last_bp; 1001 if (bp->b_blkno == bp->b_lblkno) 1002 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1003 buflist->bs_nchildren = i + 1; 1004 return (buflist); 1005 } 1006