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, "cl_savebuf", "cluster_save buffer"); 62 63 static struct cluster_save * 64 cluster_collectbufs(struct vnode *vp, struct buf *last_bp); 65 static struct buf * 66 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 67 daddr_t blkno, long size, int run, struct buf *fbp); 68 static void cluster_callback(struct buf *); 69 70 static int write_behind = 1; 71 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 72 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 73 74 static int read_max = 8; 75 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 76 "Cluster read-ahead max block count"); 77 78 /* Page expended to mark partially backed buffers */ 79 extern vm_page_t bogus_page; 80 81 /* 82 * Read data to a buf, including read-ahead if we find this to be beneficial. 83 * cluster_read replaces bread. 84 */ 85 int 86 cluster_read(vp, filesize, lblkno, size, cred, totread, seqcount, bpp) 87 struct vnode *vp; 88 u_quad_t filesize; 89 daddr_t lblkno; 90 long size; 91 struct ucred *cred; 92 long totread; 93 int seqcount; 94 struct buf **bpp; 95 { 96 struct buf *bp, *rbp, *reqbp; 97 daddr_t blkno, origblkno; 98 int maxra, racluster; 99 int error, ncontig; 100 int i; 101 102 error = 0; 103 104 /* 105 * Try to limit the amount of read-ahead by a few 106 * ad-hoc parameters. This needs work!!! 107 */ 108 racluster = vp->v_mount->mnt_iosize_max / size; 109 maxra = seqcount; 110 maxra = min(read_max, maxra); 111 maxra = min(nbuf/8, maxra); 112 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 113 maxra = (filesize / size) - lblkno; 114 115 /* 116 * get the requested block 117 */ 118 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, 0); 119 origblkno = lblkno; 120 121 /* 122 * if it is in the cache, then check to see if the reads have been 123 * sequential. If they have, then try some read-ahead, otherwise 124 * back-off on prospective read-aheads. 125 */ 126 if (bp->b_flags & B_CACHE) { 127 if (!seqcount) { 128 return 0; 129 } else if ((bp->b_flags & B_RAM) == 0) { 130 return 0; 131 } else { 132 bp->b_flags &= ~B_RAM; 133 VI_LOCK(vp); 134 for (i = 1; i < maxra; i++) { 135 /* 136 * Stop if the buffer does not exist or it 137 * is invalid (about to go away?) 138 */ 139 rbp = gbincore(&vp->v_bufobj, lblkno+i); 140 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 141 break; 142 143 /* 144 * Set another read-ahead mark so we know 145 * to check again. (If we can lock the 146 * buffer without waiting) 147 */ 148 if ((((i % racluster) == (racluster - 1)) || 149 (i == (maxra - 1))) 150 && (0 == BUF_LOCK(rbp, 151 LK_EXCLUSIVE | LK_NOWAIT, NULL))) { 152 rbp->b_flags |= B_RAM; 153 BUF_UNLOCK(rbp); 154 } 155 } 156 VI_UNLOCK(vp); 157 if (i >= maxra) { 158 return 0; 159 } 160 lblkno += i; 161 } 162 reqbp = bp = NULL; 163 /* 164 * If it isn't in the cache, then get a chunk from 165 * disk if sequential, otherwise just get the block. 166 */ 167 } else { 168 off_t firstread = bp->b_offset; 169 int nblks; 170 171 KASSERT(bp->b_offset != NOOFFSET, 172 ("cluster_read: no buffer offset")); 173 174 ncontig = 0; 175 176 /* 177 * Compute the total number of blocks that we should read 178 * synchronously. 179 */ 180 if (firstread + totread > filesize) 181 totread = filesize - firstread; 182 nblks = howmany(totread, size); 183 if (nblks > racluster) 184 nblks = racluster; 185 186 /* 187 * Now compute the number of contiguous blocks. 188 */ 189 if (nblks > 1) { 190 error = VOP_BMAP(vp, lblkno, NULL, 191 &blkno, &ncontig, NULL); 192 /* 193 * If this failed to map just do the original block. 194 */ 195 if (error || blkno == -1) 196 ncontig = 0; 197 } 198 199 /* 200 * If we have contiguous data available do a cluster 201 * otherwise just read the requested block. 202 */ 203 if (ncontig) { 204 /* Account for our first block. */ 205 ncontig = min(ncontig + 1, nblks); 206 if (ncontig < nblks) 207 nblks = ncontig; 208 bp = cluster_rbuild(vp, filesize, lblkno, 209 blkno, size, nblks, bp); 210 lblkno += (bp->b_bufsize / size); 211 } else { 212 bp->b_flags |= B_RAM; 213 bp->b_iocmd = BIO_READ; 214 lblkno += 1; 215 } 216 } 217 218 /* 219 * handle the synchronous read so that it is available ASAP. 220 */ 221 if (bp) { 222 if ((bp->b_flags & B_CLUSTER) == 0) { 223 vfs_busy_pages(bp, 0); 224 } 225 bp->b_flags &= ~B_INVAL; 226 bp->b_ioflags &= ~BIO_ERROR; 227 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 228 BUF_KERNPROC(bp); 229 bp->b_iooffset = dbtob(bp->b_blkno); 230 bstrategy(bp); 231 curthread->td_ru.ru_inblock++; 232 } 233 234 /* 235 * If we have been doing sequential I/O, then do some read-ahead. 236 */ 237 while (lblkno < (origblkno + maxra)) { 238 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 239 if (error) 240 break; 241 242 if (blkno == -1) 243 break; 244 245 /* 246 * We could throttle ncontig here by maxra but we might as 247 * well read the data if it is contiguous. We're throttled 248 * by racluster anyway. 249 */ 250 if (ncontig) { 251 ncontig = min(ncontig + 1, racluster); 252 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 253 size, ncontig, NULL); 254 lblkno += (rbp->b_bufsize / size); 255 if (rbp->b_flags & B_DELWRI) { 256 bqrelse(rbp); 257 continue; 258 } 259 } else { 260 rbp = getblk(vp, lblkno, size, 0, 0, 0); 261 lblkno += 1; 262 if (rbp->b_flags & B_DELWRI) { 263 bqrelse(rbp); 264 continue; 265 } 266 rbp->b_flags |= B_ASYNC | B_RAM; 267 rbp->b_iocmd = BIO_READ; 268 rbp->b_blkno = blkno; 269 } 270 if (rbp->b_flags & B_CACHE) { 271 rbp->b_flags &= ~B_ASYNC; 272 bqrelse(rbp); 273 continue; 274 } 275 if ((rbp->b_flags & B_CLUSTER) == 0) { 276 vfs_busy_pages(rbp, 0); 277 } 278 rbp->b_flags &= ~B_INVAL; 279 rbp->b_ioflags &= ~BIO_ERROR; 280 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 281 BUF_KERNPROC(rbp); 282 rbp->b_iooffset = dbtob(rbp->b_blkno); 283 bstrategy(rbp); 284 curthread->td_ru.ru_inblock++; 285 } 286 287 if (reqbp) 288 return (bufwait(reqbp)); 289 else 290 return (error); 291 } 292 293 /* 294 * If blocks are contiguous on disk, use this to provide clustered 295 * read ahead. We will read as many blocks as possible sequentially 296 * and then parcel them up into logical blocks in the buffer hash table. 297 */ 298 static struct buf * 299 cluster_rbuild(vp, filesize, lbn, blkno, size, run, fbp) 300 struct vnode *vp; 301 u_quad_t filesize; 302 daddr_t lbn; 303 daddr_t blkno; 304 long size; 305 int run; 306 struct buf *fbp; 307 { 308 struct buf *bp, *tbp; 309 daddr_t bn; 310 int i, inc, j; 311 312 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 313 ("cluster_rbuild: size %ld != filesize %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 } 333 334 tbp->b_blkno = blkno; 335 if( (tbp->b_flags & B_MALLOC) || 336 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 337 return tbp; 338 339 bp = trypbuf(&cluster_pbuf_freecnt); 340 if (bp == 0) 341 return tbp; 342 343 /* 344 * We are synthesizing a buffer out of vm_page_t's, but 345 * if the block size is not page aligned then the starting 346 * address may not be either. Inherit the b_data offset 347 * from the original buffer. 348 */ 349 bp->b_data = (char *)((vm_offset_t)bp->b_data | 350 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 351 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 352 bp->b_iocmd = BIO_READ; 353 bp->b_iodone = cluster_callback; 354 bp->b_blkno = blkno; 355 bp->b_lblkno = lbn; 356 bp->b_offset = tbp->b_offset; 357 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 358 pbgetvp(vp, bp); 359 360 TAILQ_INIT(&bp->b_cluster.cluster_head); 361 362 bp->b_bcount = 0; 363 bp->b_bufsize = 0; 364 bp->b_npages = 0; 365 366 inc = btodb(size); 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 VI_LOCK(vp); 388 if ((tbp->b_vflags & BV_BKGRDINPROG) || 389 (tbp->b_flags & B_CACHE) || 390 (tbp->b_flags & B_VMIO) == 0) { 391 VI_UNLOCK(vp); 392 bqrelse(tbp); 393 break; 394 } 395 VI_UNLOCK(vp); 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 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 403 for (j = 0;j < tbp->b_npages; j++) { 404 VM_OBJECT_LOCK_ASSERT(tbp->b_pages[j]->object, 405 MA_OWNED); 406 if (tbp->b_pages[j]->valid) 407 break; 408 } 409 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 410 if (j != tbp->b_npages) { 411 bqrelse(tbp); 412 break; 413 } 414 415 /* 416 * Set a read-ahead mark as appropriate 417 */ 418 if ((fbp && (i == 1)) || (i == (run - 1))) 419 tbp->b_flags |= B_RAM; 420 421 /* 422 * Set the buffer up for an async read (XXX should 423 * we do this only if we do not wind up brelse()ing?). 424 * Set the block number if it isn't set, otherwise 425 * if it is make sure it matches the block number we 426 * expect. 427 */ 428 tbp->b_flags |= B_ASYNC; 429 tbp->b_iocmd = BIO_READ; 430 if (tbp->b_blkno == tbp->b_lblkno) { 431 tbp->b_blkno = bn; 432 } else if (tbp->b_blkno != bn) { 433 brelse(tbp); 434 break; 435 } 436 } 437 /* 438 * XXX fbp from caller may not be B_ASYNC, but we are going 439 * to biodone() it in cluster_callback() anyway 440 */ 441 BUF_KERNPROC(tbp); 442 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 443 tbp, b_cluster.cluster_entry); 444 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 445 for (j = 0; j < tbp->b_npages; j += 1) { 446 vm_page_t m; 447 m = tbp->b_pages[j]; 448 vm_page_io_start(m); 449 vm_object_pip_add(m->object, 1); 450 if ((bp->b_npages == 0) || 451 (bp->b_pages[bp->b_npages-1] != m)) { 452 bp->b_pages[bp->b_npages] = m; 453 bp->b_npages++; 454 } 455 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 456 tbp->b_pages[j] = bogus_page; 457 } 458 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 459 /* 460 * XXX shouldn't this be += size for both, like in 461 * cluster_wbuild()? 462 * 463 * Don't inherit tbp->b_bufsize as it may be larger due to 464 * a non-page-aligned size. Instead just aggregate using 465 * 'size'. 466 */ 467 if (tbp->b_bcount != size) 468 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 469 if (tbp->b_bufsize != size) 470 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 471 bp->b_bcount += size; 472 bp->b_bufsize += size; 473 } 474 475 /* 476 * Fully valid pages in the cluster are already good and do not need 477 * to be re-read from disk. Replace the page with bogus_page 478 */ 479 VM_OBJECT_LOCK(bp->b_bufobj->bo_object); 480 for (j = 0; j < bp->b_npages; j++) { 481 VM_OBJECT_LOCK_ASSERT(bp->b_pages[j]->object, MA_OWNED); 482 if ((bp->b_pages[j]->valid & VM_PAGE_BITS_ALL) == 483 VM_PAGE_BITS_ALL) { 484 bp->b_pages[j] = bogus_page; 485 } 486 } 487 VM_OBJECT_UNLOCK(bp->b_bufobj->bo_object); 488 if (bp->b_bufsize > bp->b_kvasize) 489 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 490 bp->b_bufsize, bp->b_kvasize); 491 bp->b_kvasize = bp->b_bufsize; 492 493 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 494 (vm_page_t *)bp->b_pages, bp->b_npages); 495 return (bp); 496 } 497 498 /* 499 * Cleanup after a clustered read or write. 500 * This is complicated by the fact that any of the buffers might have 501 * extra memory (if there were no empty buffer headers at allocbuf time) 502 * that we will need to shift around. 503 */ 504 static void 505 cluster_callback(bp) 506 struct buf *bp; 507 { 508 struct buf *nbp, *tbp; 509 int error = 0; 510 511 /* 512 * Must propogate errors to all the components. 513 */ 514 if (bp->b_ioflags & BIO_ERROR) 515 error = bp->b_error; 516 517 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_npages); 518 /* 519 * Move memory from the large cluster buffer into the component 520 * buffers and mark IO as done on these. 521 */ 522 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 523 tbp; tbp = nbp) { 524 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 525 if (error) { 526 tbp->b_ioflags |= BIO_ERROR; 527 tbp->b_error = error; 528 } else { 529 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 530 tbp->b_flags &= ~B_INVAL; 531 tbp->b_ioflags &= ~BIO_ERROR; 532 /* 533 * XXX the bdwrite()/bqrelse() issued during 534 * cluster building clears B_RELBUF (see bqrelse() 535 * comment). If direct I/O was specified, we have 536 * to restore it here to allow the buffer and VM 537 * to be freed. 538 */ 539 if (tbp->b_flags & B_DIRECT) 540 tbp->b_flags |= B_RELBUF; 541 } 542 bufdone(tbp); 543 } 544 pbrelvp(bp); 545 relpbuf(bp, &cluster_pbuf_freecnt); 546 } 547 548 /* 549 * cluster_wbuild_wb: 550 * 551 * Implement modified write build for cluster. 552 * 553 * write_behind = 0 write behind disabled 554 * write_behind = 1 write behind normal (default) 555 * write_behind = 2 write behind backed-off 556 */ 557 558 static __inline int 559 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 560 { 561 int r = 0; 562 563 switch(write_behind) { 564 case 2: 565 if (start_lbn < len) 566 break; 567 start_lbn -= len; 568 /* FALLTHROUGH */ 569 case 1: 570 r = cluster_wbuild(vp, size, start_lbn, len); 571 /* FALLTHROUGH */ 572 default: 573 /* FALLTHROUGH */ 574 break; 575 } 576 return(r); 577 } 578 579 /* 580 * Do clustered write for FFS. 581 * 582 * Three cases: 583 * 1. Write is not sequential (write asynchronously) 584 * Write is sequential: 585 * 2. beginning of cluster - begin cluster 586 * 3. middle of a cluster - add to cluster 587 * 4. end of a cluster - asynchronously write cluster 588 */ 589 void 590 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount) 591 { 592 daddr_t lbn; 593 int maxclen, cursize; 594 int lblocksize; 595 int async; 596 597 if (vp->v_type == VREG) { 598 async = vp->v_mount->mnt_kern_flag & MNTK_ASYNC; 599 lblocksize = vp->v_mount->mnt_stat.f_iosize; 600 } else { 601 async = 0; 602 lblocksize = bp->b_bufsize; 603 } 604 lbn = bp->b_lblkno; 605 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 606 607 /* Initialize vnode to beginning of file. */ 608 if (lbn == 0) 609 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 610 611 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 612 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 613 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 614 if (vp->v_clen != 0) { 615 /* 616 * Next block is not sequential. 617 * 618 * If we are not writing at end of file, the process 619 * seeked to another point in the file since its last 620 * write, or we have reached our maximum cluster size, 621 * then push the previous cluster. Otherwise try 622 * reallocating to make it sequential. 623 * 624 * Change to algorithm: only push previous cluster if 625 * it was sequential from the point of view of the 626 * seqcount heuristic, otherwise leave the buffer 627 * intact so we can potentially optimize the I/O 628 * later on in the buf_daemon or update daemon 629 * flush. 630 */ 631 cursize = vp->v_lastw - vp->v_cstart + 1; 632 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 633 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 634 if (!async && seqcount > 0) { 635 cluster_wbuild_wb(vp, lblocksize, 636 vp->v_cstart, cursize); 637 } 638 } else { 639 struct buf **bpp, **endbp; 640 struct cluster_save *buflist; 641 642 buflist = cluster_collectbufs(vp, bp); 643 endbp = &buflist->bs_children 644 [buflist->bs_nchildren - 1]; 645 if (VOP_REALLOCBLKS(vp, buflist)) { 646 /* 647 * Failed, push the previous cluster 648 * if *really* writing sequentially 649 * in the logical file (seqcount > 1), 650 * otherwise delay it in the hopes that 651 * the low level disk driver can 652 * optimize the write ordering. 653 */ 654 for (bpp = buflist->bs_children; 655 bpp < endbp; bpp++) 656 brelse(*bpp); 657 free(buflist, M_SEGMENT); 658 if (seqcount > 1) { 659 cluster_wbuild_wb(vp, 660 lblocksize, vp->v_cstart, 661 cursize); 662 } 663 } else { 664 /* 665 * Succeeded, keep building cluster. 666 */ 667 for (bpp = buflist->bs_children; 668 bpp <= endbp; bpp++) 669 bdwrite(*bpp); 670 free(buflist, M_SEGMENT); 671 vp->v_lastw = lbn; 672 vp->v_lasta = bp->b_blkno; 673 return; 674 } 675 } 676 } 677 /* 678 * Consider beginning a cluster. If at end of file, make 679 * cluster as large as possible, otherwise find size of 680 * existing cluster. 681 */ 682 if ((vp->v_type == VREG) && 683 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 684 (bp->b_blkno == bp->b_lblkno) && 685 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 686 bp->b_blkno == -1)) { 687 bawrite(bp); 688 vp->v_clen = 0; 689 vp->v_lasta = bp->b_blkno; 690 vp->v_cstart = lbn + 1; 691 vp->v_lastw = lbn; 692 return; 693 } 694 vp->v_clen = maxclen; 695 if (!async && maxclen == 0) { /* I/O not contiguous */ 696 vp->v_cstart = lbn + 1; 697 bawrite(bp); 698 } else { /* Wait for rest of cluster */ 699 vp->v_cstart = lbn; 700 bdwrite(bp); 701 } 702 } else if (lbn == vp->v_cstart + vp->v_clen) { 703 /* 704 * At end of cluster, write it out if seqcount tells us we 705 * are operating sequentially, otherwise let the buf or 706 * update daemon handle it. 707 */ 708 bdwrite(bp); 709 if (seqcount > 1) 710 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 711 vp->v_clen = 0; 712 vp->v_cstart = lbn + 1; 713 } else if (vm_page_count_severe()) { 714 /* 715 * We are low on memory, get it going NOW 716 */ 717 bawrite(bp); 718 } else { 719 /* 720 * In the middle of a cluster, so just delay the I/O for now. 721 */ 722 bdwrite(bp); 723 } 724 vp->v_lastw = lbn; 725 vp->v_lasta = bp->b_blkno; 726 } 727 728 729 /* 730 * This is an awful lot like cluster_rbuild...wish they could be combined. 731 * The last lbn argument is the current block on which I/O is being 732 * performed. Check to see that it doesn't fall in the middle of 733 * the current block (if last_bp == NULL). 734 */ 735 int 736 cluster_wbuild(vp, size, start_lbn, len) 737 struct vnode *vp; 738 long size; 739 daddr_t start_lbn; 740 int len; 741 { 742 struct buf *bp, *tbp; 743 int i, j; 744 int totalwritten = 0; 745 int dbsize = btodb(size); 746 747 while (len > 0) { 748 /* 749 * If the buffer is not delayed-write (i.e. dirty), or it 750 * is delayed-write but either locked or inval, it cannot 751 * partake in the clustered write. 752 */ 753 VI_LOCK(vp); 754 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 755 (tbp->b_vflags & BV_BKGRDINPROG)) { 756 VI_UNLOCK(vp); 757 ++start_lbn; 758 --len; 759 continue; 760 } 761 if (BUF_LOCK(tbp, 762 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, VI_MTX(vp))) { 763 ++start_lbn; 764 --len; 765 continue; 766 } 767 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 768 BUF_UNLOCK(tbp); 769 ++start_lbn; 770 --len; 771 continue; 772 } 773 if (tbp->b_pin_count > 0) { 774 BUF_UNLOCK(tbp); 775 ++start_lbn; 776 --len; 777 continue; 778 } 779 bremfree(tbp); 780 tbp->b_flags &= ~B_DONE; 781 782 /* 783 * Extra memory in the buffer, punt on this buffer. 784 * XXX we could handle this in most cases, but we would 785 * have to push the extra memory down to after our max 786 * possible cluster size and then potentially pull it back 787 * up if the cluster was terminated prematurely--too much 788 * hassle. 789 */ 790 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 791 (B_CLUSTEROK | B_VMIO)) || 792 (tbp->b_bcount != tbp->b_bufsize) || 793 (tbp->b_bcount != size) || 794 (len == 1) || 795 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 796 totalwritten += tbp->b_bufsize; 797 bawrite(tbp); 798 ++start_lbn; 799 --len; 800 continue; 801 } 802 803 /* 804 * We got a pbuf to make the cluster in. 805 * so initialise it. 806 */ 807 TAILQ_INIT(&bp->b_cluster.cluster_head); 808 bp->b_bcount = 0; 809 bp->b_bufsize = 0; 810 bp->b_npages = 0; 811 if (tbp->b_wcred != NOCRED) 812 bp->b_wcred = crhold(tbp->b_wcred); 813 814 bp->b_blkno = tbp->b_blkno; 815 bp->b_lblkno = tbp->b_lblkno; 816 bp->b_offset = tbp->b_offset; 817 818 /* 819 * We are synthesizing a buffer out of vm_page_t's, but 820 * if the block size is not page aligned then the starting 821 * address may not be either. Inherit the b_data offset 822 * from the original buffer. 823 */ 824 bp->b_data = (char *)((vm_offset_t)bp->b_data | 825 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 826 bp->b_flags |= B_CLUSTER | 827 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 828 bp->b_iodone = cluster_callback; 829 pbgetvp(vp, bp); 830 /* 831 * From this location in the file, scan forward to see 832 * if there are buffers with adjacent data that need to 833 * be written as well. 834 */ 835 for (i = 0; i < len; ++i, ++start_lbn) { 836 if (i != 0) { /* If not the first buffer */ 837 /* 838 * If the adjacent data is not even in core it 839 * can't need to be written. 840 */ 841 VI_LOCK(vp); 842 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 843 (tbp->b_vflags & BV_BKGRDINPROG)) { 844 VI_UNLOCK(vp); 845 break; 846 } 847 848 /* 849 * If it IS in core, but has different 850 * characteristics, or is locked (which 851 * means it could be undergoing a background 852 * I/O or be in a weird state), then don't 853 * cluster with it. 854 */ 855 if (BUF_LOCK(tbp, 856 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 857 VI_MTX(vp))) 858 break; 859 860 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 861 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 862 != (B_DELWRI | B_CLUSTEROK | 863 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 864 tbp->b_wcred != bp->b_wcred) { 865 BUF_UNLOCK(tbp); 866 break; 867 } 868 869 /* 870 * Check that the combined cluster 871 * would make sense with regard to pages 872 * and would not be too large 873 */ 874 if ((tbp->b_bcount != size) || 875 ((bp->b_blkno + (dbsize * i)) != 876 tbp->b_blkno) || 877 ((tbp->b_npages + bp->b_npages) > 878 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 879 BUF_UNLOCK(tbp); 880 break; 881 } 882 883 /* 884 * Do not pull in pinned buffers. 885 */ 886 if (tbp->b_pin_count > 0) { 887 BUF_UNLOCK(tbp); 888 break; 889 } 890 891 /* 892 * Ok, it's passed all the tests, 893 * so remove it from the free list 894 * and mark it busy. We will use it. 895 */ 896 bremfree(tbp); 897 tbp->b_flags &= ~B_DONE; 898 } /* end of code for non-first buffers only */ 899 /* 900 * If the IO is via the VM then we do some 901 * special VM hackery (yuck). Since the buffer's 902 * block size may not be page-aligned it is possible 903 * for a page to be shared between two buffers. We 904 * have to get rid of the duplication when building 905 * the cluster. 906 */ 907 if (tbp->b_flags & B_VMIO) { 908 vm_page_t m; 909 910 VM_OBJECT_LOCK(tbp->b_bufobj->bo_object); 911 if (i != 0) { /* if not first buffer */ 912 for (j = 0; j < tbp->b_npages; j += 1) { 913 m = tbp->b_pages[j]; 914 if (m->oflags & VPO_BUSY) { 915 VM_OBJECT_UNLOCK( 916 tbp->b_object); 917 bqrelse(tbp); 918 goto finishcluster; 919 } 920 } 921 } 922 for (j = 0; j < tbp->b_npages; j += 1) { 923 m = tbp->b_pages[j]; 924 vm_page_io_start(m); 925 vm_object_pip_add(m->object, 1); 926 if ((bp->b_npages == 0) || 927 (bp->b_pages[bp->b_npages - 1] != m)) { 928 bp->b_pages[bp->b_npages] = m; 929 bp->b_npages++; 930 } 931 } 932 VM_OBJECT_UNLOCK(tbp->b_bufobj->bo_object); 933 } 934 bp->b_bcount += size; 935 bp->b_bufsize += size; 936 bundirty(tbp); 937 tbp->b_flags &= ~B_DONE; 938 tbp->b_ioflags &= ~BIO_ERROR; 939 tbp->b_flags |= B_ASYNC; 940 tbp->b_iocmd = BIO_WRITE; 941 reassignbuf(tbp); /* put on clean list */ 942 bufobj_wref(tbp->b_bufobj); 943 BUF_KERNPROC(tbp); 944 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 945 tbp, b_cluster.cluster_entry); 946 } 947 finishcluster: 948 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 949 (vm_page_t *) bp->b_pages, bp->b_npages); 950 if (bp->b_bufsize > bp->b_kvasize) 951 panic( 952 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 953 bp->b_bufsize, bp->b_kvasize); 954 bp->b_kvasize = bp->b_bufsize; 955 totalwritten += bp->b_bufsize; 956 bp->b_dirtyoff = 0; 957 bp->b_dirtyend = bp->b_bufsize; 958 bawrite(bp); 959 960 len -= i; 961 } 962 return totalwritten; 963 } 964 965 /* 966 * Collect together all the buffers in a cluster. 967 * Plus add one additional buffer. 968 */ 969 static struct cluster_save * 970 cluster_collectbufs(vp, last_bp) 971 struct vnode *vp; 972 struct buf *last_bp; 973 { 974 struct cluster_save *buflist; 975 struct buf *bp; 976 daddr_t lbn; 977 int i, len; 978 979 len = vp->v_lastw - vp->v_cstart + 1; 980 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 981 M_SEGMENT, M_WAITOK); 982 buflist->bs_nchildren = 0; 983 buflist->bs_children = (struct buf **) (buflist + 1); 984 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 985 (void) bread(vp, lbn, last_bp->b_bcount, NOCRED, &bp); 986 buflist->bs_children[i] = bp; 987 if (bp->b_blkno == bp->b_lblkno) 988 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 989 NULL, NULL); 990 } 991 buflist->bs_children[i] = bp = last_bp; 992 if (bp->b_blkno == bp->b_lblkno) 993 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 994 buflist->bs_nchildren = i + 1; 995 return (buflist); 996 } 997