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) 57static int rcluster= 0; 58SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, 59 "Debug VFS clustering code"); 60#endif 61 62static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer"); 63 64static struct cluster_save *cluster_collectbufs(struct vnode *vp, 65 struct buf *last_bp, int gbflags); 66static struct buf *cluster_rbuild(struct vnode *vp, u_quad_t filesize, 67 daddr_t lbn, daddr_t blkno, long size, int run, int gbflags, 68 struct buf *fbp); 69static void cluster_callback(struct buf *); 70 71static int write_behind = 1; 72SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 73 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 74 75static int read_max = 64; 76SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 77 "Cluster read-ahead max block count"); 78 79static int read_min = 1; 80SYSCTL_INT(_vfs, OID_AUTO, read_min, CTLFLAG_RW, &read_min, 0, 81 "Cluster read min block count"); 82 83/* Page expended to mark partially backed buffers */ 84extern vm_page_t bogus_page; 85 86/* 87 * Read data to a buf, including read-ahead if we find this to be beneficial. 88 * cluster_read replaces bread. 89 */ 90int 91cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, long size, 92 struct ucred *cred, long totread, int seqcount, int gbflags, 93 struct buf **bpp) 94{ 95 struct buf *bp, *rbp, *reqbp; 96 struct bufobj *bo; 97 daddr_t blkno, origblkno; 98 int maxra, racluster; 99 int error, ncontig; 100 int i; 101 102 error = 0; 103 bo = &vp->v_bufobj; 104 if (!unmapped_buf_allowed) 105 gbflags &= ~GB_UNMAPPED; 106 107 /* 108 * Try to limit the amount of read-ahead by a few 109 * ad-hoc parameters. This needs work!!! 110 */ 111 racluster = vp->v_mount->mnt_iosize_max / size; 112 maxra = seqcount; 113 maxra = min(read_max, maxra); 114 maxra = min(nbuf/8, maxra); 115 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 116 maxra = (filesize / size) - lblkno; 117 118 /* 119 * get the requested block 120 */ 121 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, gbflags); 122 origblkno = lblkno; 123 124 /* 125 * if it is in the cache, then check to see if the reads have been 126 * sequential. If they have, then try some read-ahead, otherwise 127 * back-off on prospective read-aheads. 128 */ 129 if (bp->b_flags & B_CACHE) { 130 if (!seqcount) { 131 return 0; 132 } else if ((bp->b_flags & B_RAM) == 0) { 133 return 0; 134 } else { 135 bp->b_flags &= ~B_RAM; 136 BO_RLOCK(bo); 137 for (i = 1; i < maxra; i++) { 138 /* 139 * Stop if the buffer does not exist or it 140 * is invalid (about to go away?) 141 */ 142 rbp = gbincore(&vp->v_bufobj, lblkno+i); 143 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 144 break; 145 146 /* 147 * Set another read-ahead mark so we know 148 * to check again. (If we can lock the 149 * buffer without waiting) 150 */ 151 if ((((i % racluster) == (racluster - 1)) || 152 (i == (maxra - 1))) 153 && (0 == BUF_LOCK(rbp, 154 LK_EXCLUSIVE | LK_NOWAIT, NULL))) { 155 rbp->b_flags |= B_RAM; 156 BUF_UNLOCK(rbp); 157 } 158 } 159 BO_RUNLOCK(bo); 160 if (i >= maxra) { 161 return 0; 162 } 163 lblkno += i; 164 } 165 reqbp = bp = NULL; 166 /* 167 * If it isn't in the cache, then get a chunk from 168 * disk if sequential, otherwise just get the block. 169 */ 170 } else { 171 off_t firstread = bp->b_offset; 172 int nblks; 173 long minread; 174 175 KASSERT(bp->b_offset != NOOFFSET, 176 ("cluster_read: no buffer offset")); 177 178 ncontig = 0; 179 180 /* 181 * Adjust totread if needed 182 */ 183 minread = read_min * size; 184 if (minread > totread) 185 totread = minread; 186 187 /* 188 * Compute the total number of blocks that we should read 189 * synchronously. 190 */ 191 if (firstread + totread > filesize) 192 totread = filesize - firstread; 193 nblks = howmany(totread, size); 194 if (nblks > racluster) 195 nblks = racluster; 196 197 /* 198 * Now compute the number of contiguous blocks. 199 */ 200 if (nblks > 1) { 201 error = VOP_BMAP(vp, lblkno, NULL, 202 &blkno, &ncontig, NULL); 203 /* 204 * If this failed to map just do the original block. 205 */ 206 if (error || blkno == -1) 207 ncontig = 0; 208 } 209 210 /* 211 * If we have contiguous data available do a cluster 212 * otherwise just read the requested block. 213 */ 214 if (ncontig) { 215 /* Account for our first block. */ 216 ncontig = min(ncontig + 1, nblks); 217 if (ncontig < nblks) 218 nblks = ncontig; 219 bp = cluster_rbuild(vp, filesize, lblkno, 220 blkno, size, nblks, gbflags, bp); 221 lblkno += (bp->b_bufsize / size); 222 } else { 223 bp->b_flags |= B_RAM; 224 bp->b_iocmd = BIO_READ; 225 lblkno += 1; 226 } 227 } 228 229 /* 230 * handle the synchronous read so that it is available ASAP. 231 */ 232 if (bp) { 233 if ((bp->b_flags & B_CLUSTER) == 0) { 234 vfs_busy_pages(bp, 0); 235 } 236 bp->b_flags &= ~B_INVAL; 237 bp->b_ioflags &= ~BIO_ERROR; 238 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 239 BUF_KERNPROC(bp); 240 bp->b_iooffset = dbtob(bp->b_blkno); 241 bstrategy(bp); 242 curthread->td_ru.ru_inblock++; 243 } 244 245 /* 246 * If we have been doing sequential I/O, then do some read-ahead. 247 */ 248 while (lblkno < (origblkno + maxra)) { 249 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 250 if (error) 251 break; 252 253 if (blkno == -1) 254 break; 255 256 /* 257 * We could throttle ncontig here by maxra but we might as 258 * well read the data if it is contiguous. We're throttled 259 * by racluster anyway. 260 */ 261 if (ncontig) { 262 ncontig = min(ncontig + 1, racluster); 263 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 264 size, ncontig, gbflags, NULL); 265 lblkno += (rbp->b_bufsize / size); 266 if (rbp->b_flags & B_DELWRI) { 267 bqrelse(rbp); 268 continue; 269 } 270 } else { 271 rbp = getblk(vp, lblkno, size, 0, 0, gbflags); 272 lblkno += 1; 273 if (rbp->b_flags & B_DELWRI) { 274 bqrelse(rbp); 275 continue; 276 } 277 rbp->b_flags |= B_ASYNC | B_RAM; 278 rbp->b_iocmd = BIO_READ; 279 rbp->b_blkno = blkno; 280 } 281 if (rbp->b_flags & B_CACHE) { 282 rbp->b_flags &= ~B_ASYNC; 283 bqrelse(rbp); 284 continue; 285 } 286 if ((rbp->b_flags & B_CLUSTER) == 0) { 287 vfs_busy_pages(rbp, 0); 288 } 289 rbp->b_flags &= ~B_INVAL; 290 rbp->b_ioflags &= ~BIO_ERROR; 291 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 292 BUF_KERNPROC(rbp); 293 rbp->b_iooffset = dbtob(rbp->b_blkno); 294 bstrategy(rbp); 295 curthread->td_ru.ru_inblock++; 296 } 297 298 if (reqbp) 299 return (bufwait(reqbp)); 300 else 301 return (error); 302} 303 304/* 305 * If blocks are contiguous on disk, use this to provide clustered 306 * read ahead. We will read as many blocks as possible sequentially 307 * and then parcel them up into logical blocks in the buffer hash table. 308 */ 309static struct buf * 310cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 311 daddr_t blkno, long size, int run, int gbflags, struct buf *fbp) 312{ 313 struct buf *bp, *tbp; 314 daddr_t bn; 315 off_t off; 316 long tinc, tsize; 317 int i, inc, j, k, toff; 318 319 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 320 ("cluster_rbuild: size %ld != f_iosize %jd\n", 321 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 322 323 /* 324 * avoid a division 325 */ 326 while ((u_quad_t) size * (lbn + run) > filesize) { 327 --run; 328 } 329 330 if (fbp) { 331 tbp = fbp; 332 tbp->b_iocmd = BIO_READ; 333 } else { 334 tbp = getblk(vp, lbn, size, 0, 0, gbflags); 335 if (tbp->b_flags & B_CACHE) 336 return tbp; 337 tbp->b_flags |= B_ASYNC | B_RAM; 338 tbp->b_iocmd = BIO_READ; 339 } 340 tbp->b_blkno = blkno; 341 if( (tbp->b_flags & B_MALLOC) || 342 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 343 return tbp; 344 345 bp = trypbuf(&cluster_pbuf_freecnt); 346 if (bp == 0) 347 return tbp; 348 349 /* 350 * We are synthesizing a buffer out of vm_page_t's, but 351 * if the block size is not page aligned then the starting 352 * address may not be either. Inherit the b_data offset 353 * from the original buffer. 354 */ 355 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 356 if ((gbflags & GB_UNMAPPED) != 0) { 357 bp->b_flags |= B_UNMAPPED; 358 bp->b_data = unmapped_buf; 359 } else { 360 bp->b_data = (char *)((vm_offset_t)bp->b_data | 361 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 362 } 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 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 381 vfs_drain_busy_pages(tbp); 382 vm_object_pip_add(tbp->b_bufobj->bo_object, 383 tbp->b_npages); 384 for (k = 0; k < tbp->b_npages; k++) 385 vm_page_sbusy(tbp->b_pages[k]); 386 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 387 } else { 388 if ((bp->b_npages * PAGE_SIZE) + 389 round_page(size) > vp->v_mount->mnt_iosize_max) { 390 break; 391 } 392 393 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT | 394 (gbflags & GB_UNMAPPED)); 395 396 /* Don't wait around for locked bufs. */ 397 if (tbp == NULL) 398 break; 399 400 /* 401 * Stop scanning if the buffer is fully valid 402 * (marked B_CACHE), or locked (may be doing a 403 * background write), or if the buffer is not 404 * VMIO backed. The clustering code can only deal 405 * with VMIO-backed buffers. The bo lock is not 406 * required for the BKGRDINPROG check since it 407 * can not be set without the buf lock. 408 */ 409 if ((tbp->b_vflags & BV_BKGRDINPROG) || 410 (tbp->b_flags & B_CACHE) || 411 (tbp->b_flags & B_VMIO) == 0) { 412 bqrelse(tbp); 413 break; 414 } 415 416 /* 417 * The buffer must be completely invalid in order to 418 * take part in the cluster. If it is partially valid 419 * then we stop. 420 */ 421 off = tbp->b_offset; 422 tsize = size; 423 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 424 for (j = 0; tsize > 0; j++) { 425 toff = off & PAGE_MASK; 426 tinc = tsize; 427 if (toff + tinc > PAGE_SIZE) 428 tinc = PAGE_SIZE - toff; 429 VM_OBJECT_ASSERT_WLOCKED(tbp->b_pages[j]->object); 430 if ((tbp->b_pages[j]->valid & 431 vm_page_bits(toff, tinc)) != 0) 432 break; 433 if (vm_page_xbusied(tbp->b_pages[j])) 434 break; 435 vm_object_pip_add(tbp->b_bufobj->bo_object, 1); 436 vm_page_sbusy(tbp->b_pages[j]); 437 off += tinc; 438 tsize -= tinc; 439 } 440 if (tsize > 0) { 441clean_sbusy: 442 vm_object_pip_add(tbp->b_bufobj->bo_object, -j); 443 for (k = 0; k < j; k++) 444 vm_page_sunbusy(tbp->b_pages[k]); 445 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 446 bqrelse(tbp); 447 break; 448 } 449 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 450 451 /* 452 * Set a read-ahead mark as appropriate 453 */ 454 if ((fbp && (i == 1)) || (i == (run - 1))) 455 tbp->b_flags |= B_RAM; 456 457 /* 458 * Set the buffer up for an async read (XXX should 459 * we do this only if we do not wind up brelse()ing?). 460 * Set the block number if it isn't set, otherwise 461 * if it is make sure it matches the block number we 462 * expect. 463 */ 464 tbp->b_flags |= B_ASYNC; 465 tbp->b_iocmd = BIO_READ; 466 if (tbp->b_blkno == tbp->b_lblkno) { 467 tbp->b_blkno = bn; 468 } else if (tbp->b_blkno != bn) { 469 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 470 goto clean_sbusy; 471 } 472 } 473 /* 474 * XXX fbp from caller may not be B_ASYNC, but we are going 475 * to biodone() it in cluster_callback() anyway 476 */ 477 BUF_KERNPROC(tbp); 478 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 479 tbp, b_cluster.cluster_entry); 480 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 481 for (j = 0; j < tbp->b_npages; j += 1) { 482 vm_page_t m; 483 m = tbp->b_pages[j]; 484 if ((bp->b_npages == 0) || 485 (bp->b_pages[bp->b_npages-1] != m)) { 486 bp->b_pages[bp->b_npages] = m; 487 bp->b_npages++; 488 } 489 if (m->valid == VM_PAGE_BITS_ALL) 490 tbp->b_pages[j] = bogus_page; 491 } 492 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 493 /* 494 * Don't inherit tbp->b_bufsize as it may be larger due to 495 * a non-page-aligned size. Instead just aggregate using 496 * 'size'. 497 */ 498 if (tbp->b_bcount != size) 499 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 500 if (tbp->b_bufsize != size) 501 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 502 bp->b_bcount += size; 503 bp->b_bufsize += size; 504 } 505 506 /* 507 * Fully valid pages in the cluster are already good and do not need 508 * to be re-read from disk. Replace the page with bogus_page 509 */ 510 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 511 for (j = 0; j < bp->b_npages; j++) { 512 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[j]->object); 513 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL) 514 bp->b_pages[j] = bogus_page; 515 } 516 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 517 if (bp->b_bufsize > bp->b_kvasize) 518 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 519 bp->b_bufsize, bp->b_kvasize); 520 bp->b_kvasize = bp->b_bufsize; 521 522 if ((bp->b_flags & B_UNMAPPED) == 0) { 523 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 524 (vm_page_t *)bp->b_pages, bp->b_npages); 525 } 526 return (bp); 527} 528 529/* 530 * Cleanup after a clustered read or write. 531 * This is complicated by the fact that any of the buffers might have 532 * extra memory (if there were no empty buffer headers at allocbuf time) 533 * that we will need to shift around. 534 */ 535static void 536cluster_callback(bp) 537 struct buf *bp; 538{ 539 struct buf *nbp, *tbp; 540 int error = 0; 541 542 /* 543 * Must propagate errors to all the components. 544 */ 545 if (bp->b_ioflags & BIO_ERROR) 546 error = bp->b_error; 547 548 if ((bp->b_flags & B_UNMAPPED) == 0) { 549 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), 550 bp->b_npages); 551 } 552 /* 553 * Move memory from the large cluster buffer into the component 554 * buffers and mark IO as done on these. 555 */ 556 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 557 tbp; tbp = nbp) { 558 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 559 if (error) { 560 tbp->b_ioflags |= BIO_ERROR; 561 tbp->b_error = error; 562 } else { 563 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 564 tbp->b_flags &= ~B_INVAL; 565 tbp->b_ioflags &= ~BIO_ERROR; 566 /* 567 * XXX the bdwrite()/bqrelse() issued during 568 * cluster building clears B_RELBUF (see bqrelse() 569 * comment). If direct I/O was specified, we have 570 * to restore it here to allow the buffer and VM 571 * to be freed. 572 */ 573 if (tbp->b_flags & B_DIRECT) 574 tbp->b_flags |= B_RELBUF; 575 } 576 bufdone(tbp); 577 } 578 pbrelvp(bp); 579 relpbuf(bp, &cluster_pbuf_freecnt); 580} 581 582/* 583 * cluster_wbuild_wb: 584 * 585 * Implement modified write build for cluster. 586 * 587 * write_behind = 0 write behind disabled 588 * write_behind = 1 write behind normal (default) 589 * write_behind = 2 write behind backed-off 590 */ 591 592static __inline int 593cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len, 594 int gbflags) 595{ 596 int r = 0; 597 598 switch (write_behind) { 599 case 2: 600 if (start_lbn < len) 601 break; 602 start_lbn -= len; 603 /* FALLTHROUGH */ 604 case 1: 605 r = cluster_wbuild(vp, size, start_lbn, len, gbflags); 606 /* FALLTHROUGH */ 607 default: 608 /* FALLTHROUGH */ 609 break; 610 } 611 return(r); 612} 613 614/* 615 * Do clustered write for FFS. 616 * 617 * Three cases: 618 * 1. Write is not sequential (write asynchronously) 619 * Write is sequential: 620 * 2. beginning of cluster - begin cluster 621 * 3. middle of a cluster - add to cluster 622 * 4. end of a cluster - asynchronously write cluster 623 */ 624void 625cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount, 626 int gbflags) 627{ 628 daddr_t lbn; 629 int maxclen, cursize; 630 int lblocksize; 631 int async; 632 633 if (!unmapped_buf_allowed) 634 gbflags &= ~GB_UNMAPPED; 635 636 if (vp->v_type == VREG) { 637 async = DOINGASYNC(vp); 638 lblocksize = vp->v_mount->mnt_stat.f_iosize; 639 } else { 640 async = 0; 641 lblocksize = bp->b_bufsize; 642 } 643 lbn = bp->b_lblkno; 644 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 645 646 /* Initialize vnode to beginning of file. */ 647 if (lbn == 0) 648 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 649 650 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 651 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 652 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 653 if (vp->v_clen != 0) { 654 /* 655 * Next block is not sequential. 656 * 657 * If we are not writing at end of file, the process 658 * seeked to another point in the file since its last 659 * write, or we have reached our maximum cluster size, 660 * then push the previous cluster. Otherwise try 661 * reallocating to make it sequential. 662 * 663 * Change to algorithm: only push previous cluster if 664 * it was sequential from the point of view of the 665 * seqcount heuristic, otherwise leave the buffer 666 * intact so we can potentially optimize the I/O 667 * later on in the buf_daemon or update daemon 668 * flush. 669 */ 670 cursize = vp->v_lastw - vp->v_cstart + 1; 671 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 672 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 673 if (!async && seqcount > 0) { 674 cluster_wbuild_wb(vp, lblocksize, 675 vp->v_cstart, cursize, gbflags); 676 } 677 } else { 678 struct buf **bpp, **endbp; 679 struct cluster_save *buflist; 680 681 buflist = cluster_collectbufs(vp, bp, gbflags); 682 endbp = &buflist->bs_children 683 [buflist->bs_nchildren - 1]; 684 if (VOP_REALLOCBLKS(vp, buflist)) { 685 /* 686 * Failed, push the previous cluster 687 * if *really* writing sequentially 688 * in the logical file (seqcount > 1), 689 * otherwise delay it in the hopes that 690 * the low level disk driver can 691 * optimize the write ordering. 692 */ 693 for (bpp = buflist->bs_children; 694 bpp < endbp; bpp++) 695 brelse(*bpp); 696 free(buflist, M_SEGMENT); 697 if (seqcount > 1) { 698 cluster_wbuild_wb(vp, 699 lblocksize, vp->v_cstart, 700 cursize, gbflags); 701 } 702 } else { 703 /* 704 * Succeeded, keep building cluster. 705 */ 706 for (bpp = buflist->bs_children; 707 bpp <= endbp; bpp++) 708 bdwrite(*bpp); 709 free(buflist, M_SEGMENT); 710 vp->v_lastw = lbn; 711 vp->v_lasta = bp->b_blkno; 712 return; 713 } 714 } 715 } 716 /* 717 * Consider beginning a cluster. If at end of file, make 718 * cluster as large as possible, otherwise find size of 719 * existing cluster. 720 */ 721 if ((vp->v_type == VREG) && 722 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 723 (bp->b_blkno == bp->b_lblkno) && 724 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 725 bp->b_blkno == -1)) { 726 bawrite(bp); 727 vp->v_clen = 0; 728 vp->v_lasta = bp->b_blkno; 729 vp->v_cstart = lbn + 1; 730 vp->v_lastw = lbn; 731 return; 732 } 733 vp->v_clen = maxclen; 734 if (!async && maxclen == 0) { /* I/O not contiguous */ 735 vp->v_cstart = lbn + 1; 736 bawrite(bp); 737 } else { /* Wait for rest of cluster */ 738 vp->v_cstart = lbn; 739 bdwrite(bp); 740 } 741 } else if (lbn == vp->v_cstart + vp->v_clen) { 742 /* 743 * At end of cluster, write it out if seqcount tells us we 744 * are operating sequentially, otherwise let the buf or 745 * update daemon handle it. 746 */ 747 bdwrite(bp); 748 if (seqcount > 1) { 749 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, 750 vp->v_clen + 1, gbflags); 751 } 752 vp->v_clen = 0; 753 vp->v_cstart = lbn + 1; 754 } else if (vm_page_count_severe()) { 755 /* 756 * We are low on memory, get it going NOW 757 */ 758 bawrite(bp); 759 } else { 760 /* 761 * In the middle of a cluster, so just delay the I/O for now. 762 */ 763 bdwrite(bp); 764 } 765 vp->v_lastw = lbn; 766 vp->v_lasta = bp->b_blkno; 767} 768 769 770/* 771 * This is an awful lot like cluster_rbuild...wish they could be combined. 772 * The last lbn argument is the current block on which I/O is being 773 * performed. Check to see that it doesn't fall in the middle of 774 * the current block (if last_bp == NULL). 775 */ 776int 777cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len, 778 int gbflags) 779{ 780 struct buf *bp, *tbp; 781 struct bufobj *bo; 782 int i, j; 783 int totalwritten = 0; 784 int dbsize = btodb(size); 785 786 if (!unmapped_buf_allowed) 787 gbflags &= ~GB_UNMAPPED; 788 789 bo = &vp->v_bufobj; 790 while (len > 0) { 791 /* 792 * If the buffer is not delayed-write (i.e. dirty), or it 793 * is delayed-write but either locked or inval, it cannot 794 * partake in the clustered write. 795 */ 796 BO_LOCK(bo); 797 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 798 (tbp->b_vflags & BV_BKGRDINPROG)) { 799 BO_UNLOCK(bo); 800 ++start_lbn; 801 --len; 802 continue; 803 } 804 if (BUF_LOCK(tbp, 805 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_LOCKPTR(bo))) { 806 ++start_lbn; 807 --len; 808 continue; 809 } 810 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 811 BUF_UNLOCK(tbp); 812 ++start_lbn; 813 --len; 814 continue; 815 } 816 if (tbp->b_pin_count > 0) { 817 BUF_UNLOCK(tbp); 818 ++start_lbn; 819 --len; 820 continue; 821 } 822 bremfree(tbp); 823 tbp->b_flags &= ~B_DONE; 824 825 /* 826 * Extra memory in the buffer, punt on this buffer. 827 * XXX we could handle this in most cases, but we would 828 * have to push the extra memory down to after our max 829 * possible cluster size and then potentially pull it back 830 * up if the cluster was terminated prematurely--too much 831 * hassle. 832 */ 833 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 834 (B_CLUSTEROK | B_VMIO)) || 835 (tbp->b_bcount != tbp->b_bufsize) || 836 (tbp->b_bcount != size) || 837 (len == 1) || 838 ((bp = (vp->v_vflag & VV_MD) != 0 ? 839 trypbuf(&cluster_pbuf_freecnt) : 840 getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 841 totalwritten += tbp->b_bufsize; 842 bawrite(tbp); 843 ++start_lbn; 844 --len; 845 continue; 846 } 847 848 /* 849 * We got a pbuf to make the cluster in. 850 * so initialise it. 851 */ 852 TAILQ_INIT(&bp->b_cluster.cluster_head); 853 bp->b_bcount = 0; 854 bp->b_bufsize = 0; 855 bp->b_npages = 0; 856 if (tbp->b_wcred != NOCRED) 857 bp->b_wcred = crhold(tbp->b_wcred); 858 859 bp->b_blkno = tbp->b_blkno; 860 bp->b_lblkno = tbp->b_lblkno; 861 bp->b_offset = tbp->b_offset; 862 863 /* 864 * We are synthesizing a buffer out of vm_page_t's, but 865 * if the block size is not page aligned then the starting 866 * address may not be either. Inherit the b_data offset 867 * from the original buffer. 868 */ 869 if ((gbflags & GB_UNMAPPED) == 0 || 870 (tbp->b_flags & B_VMIO) == 0) { 871 bp->b_data = (char *)((vm_offset_t)bp->b_data | 872 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 873 } else { 874 bp->b_flags |= B_UNMAPPED; 875 bp->b_data = unmapped_buf; 876 } 877 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO | 878 B_NEEDCOMMIT)); 879 bp->b_iodone = cluster_callback; 880 pbgetvp(vp, bp); 881 /* 882 * From this location in the file, scan forward to see 883 * if there are buffers with adjacent data that need to 884 * be written as well. 885 */ 886 for (i = 0; i < len; ++i, ++start_lbn) { 887 if (i != 0) { /* If not the first buffer */ 888 /* 889 * If the adjacent data is not even in core it 890 * can't need to be written. 891 */ 892 BO_LOCK(bo); 893 if ((tbp = gbincore(bo, start_lbn)) == NULL || 894 (tbp->b_vflags & BV_BKGRDINPROG)) { 895 BO_UNLOCK(bo); 896 break; 897 } 898 899 /* 900 * If it IS in core, but has different 901 * characteristics, or is locked (which 902 * means it could be undergoing a background 903 * I/O or be in a weird state), then don't 904 * cluster with it. 905 */ 906 if (BUF_LOCK(tbp, 907 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 908 BO_LOCKPTR(bo))) 909 break; 910 911 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 912 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 913 != (B_DELWRI | B_CLUSTEROK | 914 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 915 tbp->b_wcred != bp->b_wcred) { 916 BUF_UNLOCK(tbp); 917 break; 918 } 919 920 /* 921 * Check that the combined cluster 922 * would make sense with regard to pages 923 * and would not be too large 924 */ 925 if ((tbp->b_bcount != size) || 926 ((bp->b_blkno + (dbsize * i)) != 927 tbp->b_blkno) || 928 ((tbp->b_npages + bp->b_npages) > 929 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 930 BUF_UNLOCK(tbp); 931 break; 932 } 933 934 /* 935 * Do not pull in pinned buffers. 936 */ 937 if (tbp->b_pin_count > 0) { 938 BUF_UNLOCK(tbp); 939 break; 940 } 941 942 /* 943 * Ok, it's passed all the tests, 944 * so remove it from the free list 945 * and mark it busy. We will use it. 946 */ 947 bremfree(tbp); 948 tbp->b_flags &= ~B_DONE; 949 } /* end of code for non-first buffers only */ 950 /* 951 * If the IO is via the VM then we do some 952 * special VM hackery (yuck). Since the buffer's 953 * block size may not be page-aligned it is possible 954 * for a page to be shared between two buffers. We 955 * have to get rid of the duplication when building 956 * the cluster. 957 */ 958 if (tbp->b_flags & B_VMIO) { 959 vm_page_t m; 960 961 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 962 if (i == 0) { 963 vfs_drain_busy_pages(tbp); 964 } else { /* if not first buffer */ 965 for (j = 0; j < tbp->b_npages; j += 1) { 966 m = tbp->b_pages[j]; 967 if (vm_page_xbusied(m)) { 968 VM_OBJECT_WUNLOCK( 969 tbp->b_object); 970 bqrelse(tbp); 971 goto finishcluster; 972 } 973 } 974 } 975 for (j = 0; j < tbp->b_npages; j += 1) { 976 m = tbp->b_pages[j]; 977 vm_page_sbusy(m); 978 vm_object_pip_add(m->object, 1); 979 if ((bp->b_npages == 0) || 980 (bp->b_pages[bp->b_npages - 1] != m)) { 981 bp->b_pages[bp->b_npages] = m; 982 bp->b_npages++; 983 } 984 } 985 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 986 } 987 bp->b_bcount += size; 988 bp->b_bufsize += size; 989 /* 990 * If any of the clustered buffers have their 991 * B_BARRIER flag set, transfer that request to 992 * the cluster. 993 */ 994 bp->b_flags |= (tbp->b_flags & B_BARRIER); 995 tbp->b_flags &= ~(B_DONE | B_BARRIER); 996 tbp->b_flags |= B_ASYNC; 997 tbp->b_ioflags &= ~BIO_ERROR; 998 tbp->b_iocmd = BIO_WRITE; 999 bundirty(tbp); 1000 reassignbuf(tbp); /* put on clean list */ 1001 bufobj_wref(tbp->b_bufobj); 1002 BUF_KERNPROC(tbp); 1003 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 1004 tbp, b_cluster.cluster_entry); 1005 } 1006 finishcluster: 1007 if ((bp->b_flags & B_UNMAPPED) == 0) { 1008 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 1009 (vm_page_t *)bp->b_pages, bp->b_npages); 1010 } 1011 if (bp->b_bufsize > bp->b_kvasize) 1012 panic( 1013 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 1014 bp->b_bufsize, bp->b_kvasize); 1015 bp->b_kvasize = bp->b_bufsize; 1016 totalwritten += bp->b_bufsize; 1017 bp->b_dirtyoff = 0; 1018 bp->b_dirtyend = bp->b_bufsize; 1019 bawrite(bp); 1020 1021 len -= i; 1022 } 1023 return totalwritten; 1024} 1025 1026/* 1027 * Collect together all the buffers in a cluster. 1028 * Plus add one additional buffer. 1029 */ 1030static struct cluster_save * 1031cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int gbflags) 1032{ 1033 struct cluster_save *buflist; 1034 struct buf *bp; 1035 daddr_t lbn; 1036 int i, len; 1037 1038 len = vp->v_lastw - vp->v_cstart + 1; 1039 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 1040 M_SEGMENT, M_WAITOK); 1041 buflist->bs_nchildren = 0; 1042 buflist->bs_children = (struct buf **) (buflist + 1); 1043 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 1044 (void)bread_gb(vp, lbn, last_bp->b_bcount, NOCRED, 1045 gbflags, &bp); 1046 buflist->bs_children[i] = bp; 1047 if (bp->b_blkno == bp->b_lblkno) 1048 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 1049 NULL, NULL); 1050 } 1051 buflist->bs_children[i] = bp = last_bp; 1052 if (bp->b_blkno == bp->b_lblkno) 1053 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1054 buflist->bs_nchildren = i + 1; 1055 return (buflist); 1056} 1057