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 *cluster_collectbufs(struct vnode *vp, 65 struct buf *last_bp, int gbflags); 66 static 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); 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 static int read_min = 1; 80 SYSCTL_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 */ 84 extern 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 */ 90 int 91 cluster_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 */ 309 static struct buf * 310 cluster_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 bufobj *bo; 314 struct buf *bp, *tbp; 315 daddr_t bn; 316 off_t off; 317 long tinc, tsize; 318 int i, inc, j, toff; 319 320 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 321 ("cluster_rbuild: size %ld != f_iosize %jd\n", 322 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 323 324 /* 325 * avoid a division 326 */ 327 while ((u_quad_t) size * (lbn + run) > filesize) { 328 --run; 329 } 330 331 if (fbp) { 332 tbp = fbp; 333 tbp->b_iocmd = BIO_READ; 334 } else { 335 tbp = getblk(vp, lbn, size, 0, 0, gbflags); 336 if (tbp->b_flags & B_CACHE) 337 return tbp; 338 tbp->b_flags |= B_ASYNC | B_RAM; 339 tbp->b_iocmd = BIO_READ; 340 } 341 tbp->b_blkno = blkno; 342 if( (tbp->b_flags & B_MALLOC) || 343 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 344 return tbp; 345 346 bp = trypbuf(&cluster_pbuf_freecnt); 347 if (bp == 0) 348 return tbp; 349 350 /* 351 * We are synthesizing a buffer out of vm_page_t's, but 352 * if the block size is not page aligned then the starting 353 * address may not be either. Inherit the b_data offset 354 * from the original buffer. 355 */ 356 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 357 if ((gbflags & GB_UNMAPPED) != 0) { 358 bp->b_flags |= B_UNMAPPED; 359 bp->b_data = unmapped_buf; 360 } else { 361 bp->b_data = (char *)((vm_offset_t)bp->b_data | 362 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 363 } 364 bp->b_iocmd = BIO_READ; 365 bp->b_iodone = cluster_callback; 366 bp->b_blkno = blkno; 367 bp->b_lblkno = lbn; 368 bp->b_offset = tbp->b_offset; 369 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 370 pbgetvp(vp, bp); 371 372 TAILQ_INIT(&bp->b_cluster.cluster_head); 373 374 bp->b_bcount = 0; 375 bp->b_bufsize = 0; 376 bp->b_npages = 0; 377 378 inc = btodb(size); 379 bo = &vp->v_bufobj; 380 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 381 if (i != 0) { 382 if ((bp->b_npages * PAGE_SIZE) + 383 round_page(size) > vp->v_mount->mnt_iosize_max) { 384 break; 385 } 386 387 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT | 388 (gbflags & GB_UNMAPPED)); 389 390 /* Don't wait around for locked bufs. */ 391 if (tbp == NULL) 392 break; 393 394 /* 395 * Stop scanning if the buffer is fully valid 396 * (marked B_CACHE), or locked (may be doing a 397 * background write), or if the buffer is not 398 * VMIO backed. The clustering code can only deal 399 * with VMIO-backed buffers. The bo lock is not 400 * required for the BKGRDINPROG check since it 401 * can not be set without the buf lock. 402 */ 403 if ((tbp->b_vflags & BV_BKGRDINPROG) || 404 (tbp->b_flags & B_CACHE) || 405 (tbp->b_flags & B_VMIO) == 0) { 406 bqrelse(tbp); 407 break; 408 } 409 410 /* 411 * The buffer must be completely invalid in order to 412 * take part in the cluster. If it is partially valid 413 * then we stop. 414 */ 415 off = tbp->b_offset; 416 tsize = size; 417 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 418 for (j = 0; tsize > 0; j++) { 419 toff = off & PAGE_MASK; 420 tinc = tsize; 421 if (toff + tinc > PAGE_SIZE) 422 tinc = PAGE_SIZE - toff; 423 VM_OBJECT_ASSERT_WLOCKED(tbp->b_pages[j]->object); 424 if ((tbp->b_pages[j]->valid & 425 vm_page_bits(toff, tinc)) != 0) 426 break; 427 off += tinc; 428 tsize -= tinc; 429 } 430 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 431 if (tsize > 0) { 432 bqrelse(tbp); 433 break; 434 } 435 436 /* 437 * Set a read-ahead mark as appropriate 438 */ 439 if ((fbp && (i == 1)) || (i == (run - 1))) 440 tbp->b_flags |= B_RAM; 441 442 /* 443 * Set the buffer up for an async read (XXX should 444 * we do this only if we do not wind up brelse()ing?). 445 * Set the block number if it isn't set, otherwise 446 * if it is make sure it matches the block number we 447 * expect. 448 */ 449 tbp->b_flags |= B_ASYNC; 450 tbp->b_iocmd = BIO_READ; 451 if (tbp->b_blkno == tbp->b_lblkno) { 452 tbp->b_blkno = bn; 453 } else if (tbp->b_blkno != bn) { 454 brelse(tbp); 455 break; 456 } 457 } 458 /* 459 * XXX fbp from caller may not be B_ASYNC, but we are going 460 * to biodone() it in cluster_callback() anyway 461 */ 462 BUF_KERNPROC(tbp); 463 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 464 tbp, b_cluster.cluster_entry); 465 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 466 for (j = 0; j < tbp->b_npages; j += 1) { 467 vm_page_t m; 468 m = tbp->b_pages[j]; 469 vm_page_io_start(m); 470 vm_object_pip_add(m->object, 1); 471 if ((bp->b_npages == 0) || 472 (bp->b_pages[bp->b_npages-1] != m)) { 473 bp->b_pages[bp->b_npages] = m; 474 bp->b_npages++; 475 } 476 if (m->valid == VM_PAGE_BITS_ALL) 477 tbp->b_pages[j] = bogus_page; 478 } 479 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 480 /* 481 * Don't inherit tbp->b_bufsize as it may be larger due to 482 * a non-page-aligned size. Instead just aggregate using 483 * 'size'. 484 */ 485 if (tbp->b_bcount != size) 486 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 487 if (tbp->b_bufsize != size) 488 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 489 bp->b_bcount += size; 490 bp->b_bufsize += size; 491 } 492 493 /* 494 * Fully valid pages in the cluster are already good and do not need 495 * to be re-read from disk. Replace the page with bogus_page 496 */ 497 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 498 for (j = 0; j < bp->b_npages; j++) { 499 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[j]->object); 500 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL) 501 bp->b_pages[j] = bogus_page; 502 } 503 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 504 if (bp->b_bufsize > bp->b_kvasize) 505 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 506 bp->b_bufsize, bp->b_kvasize); 507 bp->b_kvasize = bp->b_bufsize; 508 509 if ((bp->b_flags & B_UNMAPPED) == 0) { 510 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 511 (vm_page_t *)bp->b_pages, bp->b_npages); 512 } 513 return (bp); 514 } 515 516 /* 517 * Cleanup after a clustered read or write. 518 * This is complicated by the fact that any of the buffers might have 519 * extra memory (if there were no empty buffer headers at allocbuf time) 520 * that we will need to shift around. 521 */ 522 static void 523 cluster_callback(bp) 524 struct buf *bp; 525 { 526 struct buf *nbp, *tbp; 527 int error = 0; 528 529 /* 530 * Must propogate errors to all the components. 531 */ 532 if (bp->b_ioflags & BIO_ERROR) 533 error = bp->b_error; 534 535 if ((bp->b_flags & B_UNMAPPED) == 0) { 536 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), 537 bp->b_npages); 538 } 539 /* 540 * Move memory from the large cluster buffer into the component 541 * buffers and mark IO as done on these. 542 */ 543 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 544 tbp; tbp = nbp) { 545 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 546 if (error) { 547 tbp->b_ioflags |= BIO_ERROR; 548 tbp->b_error = error; 549 } else { 550 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 551 tbp->b_flags &= ~B_INVAL; 552 tbp->b_ioflags &= ~BIO_ERROR; 553 /* 554 * XXX the bdwrite()/bqrelse() issued during 555 * cluster building clears B_RELBUF (see bqrelse() 556 * comment). If direct I/O was specified, we have 557 * to restore it here to allow the buffer and VM 558 * to be freed. 559 */ 560 if (tbp->b_flags & B_DIRECT) 561 tbp->b_flags |= B_RELBUF; 562 } 563 bufdone(tbp); 564 } 565 pbrelvp(bp); 566 relpbuf(bp, &cluster_pbuf_freecnt); 567 } 568 569 /* 570 * cluster_wbuild_wb: 571 * 572 * Implement modified write build for cluster. 573 * 574 * write_behind = 0 write behind disabled 575 * write_behind = 1 write behind normal (default) 576 * write_behind = 2 write behind backed-off 577 */ 578 579 static __inline int 580 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len, 581 int gbflags) 582 { 583 int r = 0; 584 585 switch (write_behind) { 586 case 2: 587 if (start_lbn < len) 588 break; 589 start_lbn -= len; 590 /* FALLTHROUGH */ 591 case 1: 592 r = cluster_wbuild(vp, size, start_lbn, len, gbflags); 593 /* FALLTHROUGH */ 594 default: 595 /* FALLTHROUGH */ 596 break; 597 } 598 return(r); 599 } 600 601 /* 602 * Do clustered write for FFS. 603 * 604 * Three cases: 605 * 1. Write is not sequential (write asynchronously) 606 * Write is sequential: 607 * 2. beginning of cluster - begin cluster 608 * 3. middle of a cluster - add to cluster 609 * 4. end of a cluster - asynchronously write cluster 610 */ 611 void 612 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount, 613 int gbflags) 614 { 615 daddr_t lbn; 616 int maxclen, cursize; 617 int lblocksize; 618 int async; 619 620 if (!unmapped_buf_allowed) 621 gbflags &= ~GB_UNMAPPED; 622 623 if (vp->v_type == VREG) { 624 async = DOINGASYNC(vp); 625 lblocksize = vp->v_mount->mnt_stat.f_iosize; 626 } else { 627 async = 0; 628 lblocksize = bp->b_bufsize; 629 } 630 lbn = bp->b_lblkno; 631 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 632 633 /* Initialize vnode to beginning of file. */ 634 if (lbn == 0) 635 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 636 637 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 638 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 639 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 640 if (vp->v_clen != 0) { 641 /* 642 * Next block is not sequential. 643 * 644 * If we are not writing at end of file, the process 645 * seeked to another point in the file since its last 646 * write, or we have reached our maximum cluster size, 647 * then push the previous cluster. Otherwise try 648 * reallocating to make it sequential. 649 * 650 * Change to algorithm: only push previous cluster if 651 * it was sequential from the point of view of the 652 * seqcount heuristic, otherwise leave the buffer 653 * intact so we can potentially optimize the I/O 654 * later on in the buf_daemon or update daemon 655 * flush. 656 */ 657 cursize = vp->v_lastw - vp->v_cstart + 1; 658 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 659 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 660 if (!async && seqcount > 0) { 661 cluster_wbuild_wb(vp, lblocksize, 662 vp->v_cstart, cursize, gbflags); 663 } 664 } else { 665 struct buf **bpp, **endbp; 666 struct cluster_save *buflist; 667 668 buflist = cluster_collectbufs(vp, bp, gbflags); 669 endbp = &buflist->bs_children 670 [buflist->bs_nchildren - 1]; 671 if (VOP_REALLOCBLKS(vp, buflist)) { 672 /* 673 * Failed, push the previous cluster 674 * if *really* writing sequentially 675 * in the logical file (seqcount > 1), 676 * otherwise delay it in the hopes that 677 * the low level disk driver can 678 * optimize the write ordering. 679 */ 680 for (bpp = buflist->bs_children; 681 bpp < endbp; bpp++) 682 brelse(*bpp); 683 free(buflist, M_SEGMENT); 684 if (seqcount > 1) { 685 cluster_wbuild_wb(vp, 686 lblocksize, vp->v_cstart, 687 cursize, gbflags); 688 } 689 } else { 690 /* 691 * Succeeded, keep building cluster. 692 */ 693 for (bpp = buflist->bs_children; 694 bpp <= endbp; bpp++) 695 bdwrite(*bpp); 696 free(buflist, M_SEGMENT); 697 vp->v_lastw = lbn; 698 vp->v_lasta = bp->b_blkno; 699 return; 700 } 701 } 702 } 703 /* 704 * Consider beginning a cluster. If at end of file, make 705 * cluster as large as possible, otherwise find size of 706 * existing cluster. 707 */ 708 if ((vp->v_type == VREG) && 709 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 710 (bp->b_blkno == bp->b_lblkno) && 711 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 712 bp->b_blkno == -1)) { 713 bawrite(bp); 714 vp->v_clen = 0; 715 vp->v_lasta = bp->b_blkno; 716 vp->v_cstart = lbn + 1; 717 vp->v_lastw = lbn; 718 return; 719 } 720 vp->v_clen = maxclen; 721 if (!async && maxclen == 0) { /* I/O not contiguous */ 722 vp->v_cstart = lbn + 1; 723 bawrite(bp); 724 } else { /* Wait for rest of cluster */ 725 vp->v_cstart = lbn; 726 bdwrite(bp); 727 } 728 } else if (lbn == vp->v_cstart + vp->v_clen) { 729 /* 730 * At end of cluster, write it out if seqcount tells us we 731 * are operating sequentially, otherwise let the buf or 732 * update daemon handle it. 733 */ 734 bdwrite(bp); 735 if (seqcount > 1) { 736 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, 737 vp->v_clen + 1, gbflags); 738 } 739 vp->v_clen = 0; 740 vp->v_cstart = lbn + 1; 741 } else if (vm_page_count_severe()) { 742 /* 743 * We are low on memory, get it going NOW 744 */ 745 bawrite(bp); 746 } else { 747 /* 748 * In the middle of a cluster, so just delay the I/O for now. 749 */ 750 bdwrite(bp); 751 } 752 vp->v_lastw = lbn; 753 vp->v_lasta = bp->b_blkno; 754 } 755 756 757 /* 758 * This is an awful lot like cluster_rbuild...wish they could be combined. 759 * The last lbn argument is the current block on which I/O is being 760 * performed. Check to see that it doesn't fall in the middle of 761 * the current block (if last_bp == NULL). 762 */ 763 int 764 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len, 765 int gbflags) 766 { 767 struct buf *bp, *tbp; 768 struct bufobj *bo; 769 int i, j; 770 int totalwritten = 0; 771 int dbsize = btodb(size); 772 773 if (!unmapped_buf_allowed) 774 gbflags &= ~GB_UNMAPPED; 775 776 bo = &vp->v_bufobj; 777 while (len > 0) { 778 /* 779 * If the buffer is not delayed-write (i.e. dirty), or it 780 * is delayed-write but either locked or inval, it cannot 781 * partake in the clustered write. 782 */ 783 BO_LOCK(bo); 784 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 785 (tbp->b_vflags & BV_BKGRDINPROG)) { 786 BO_UNLOCK(bo); 787 ++start_lbn; 788 --len; 789 continue; 790 } 791 if (BUF_LOCK(tbp, 792 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_LOCKPTR(bo))) { 793 ++start_lbn; 794 --len; 795 continue; 796 } 797 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 798 BUF_UNLOCK(tbp); 799 ++start_lbn; 800 --len; 801 continue; 802 } 803 if (tbp->b_pin_count > 0) { 804 BUF_UNLOCK(tbp); 805 ++start_lbn; 806 --len; 807 continue; 808 } 809 bremfree(tbp); 810 tbp->b_flags &= ~B_DONE; 811 812 /* 813 * Extra memory in the buffer, punt on this buffer. 814 * XXX we could handle this in most cases, but we would 815 * have to push the extra memory down to after our max 816 * possible cluster size and then potentially pull it back 817 * up if the cluster was terminated prematurely--too much 818 * hassle. 819 */ 820 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 821 (B_CLUSTEROK | B_VMIO)) || 822 (tbp->b_bcount != tbp->b_bufsize) || 823 (tbp->b_bcount != size) || 824 (len == 1) || 825 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 826 totalwritten += tbp->b_bufsize; 827 bawrite(tbp); 828 ++start_lbn; 829 --len; 830 continue; 831 } 832 833 /* 834 * We got a pbuf to make the cluster in. 835 * so initialise it. 836 */ 837 TAILQ_INIT(&bp->b_cluster.cluster_head); 838 bp->b_bcount = 0; 839 bp->b_bufsize = 0; 840 bp->b_npages = 0; 841 if (tbp->b_wcred != NOCRED) 842 bp->b_wcred = crhold(tbp->b_wcred); 843 844 bp->b_blkno = tbp->b_blkno; 845 bp->b_lblkno = tbp->b_lblkno; 846 bp->b_offset = tbp->b_offset; 847 848 /* 849 * We are synthesizing a buffer out of vm_page_t's, but 850 * if the block size is not page aligned then the starting 851 * address may not be either. Inherit the b_data offset 852 * from the original buffer. 853 */ 854 if ((gbflags & GB_UNMAPPED) == 0 || 855 (tbp->b_flags & B_VMIO) == 0) { 856 bp->b_data = (char *)((vm_offset_t)bp->b_data | 857 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 858 } else { 859 bp->b_flags |= B_UNMAPPED; 860 bp->b_data = unmapped_buf; 861 } 862 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO | 863 B_NEEDCOMMIT)); 864 bp->b_iodone = cluster_callback; 865 pbgetvp(vp, bp); 866 /* 867 * From this location in the file, scan forward to see 868 * if there are buffers with adjacent data that need to 869 * be written as well. 870 */ 871 for (i = 0; i < len; ++i, ++start_lbn) { 872 if (i != 0) { /* If not the first buffer */ 873 /* 874 * If the adjacent data is not even in core it 875 * can't need to be written. 876 */ 877 BO_LOCK(bo); 878 if ((tbp = gbincore(bo, start_lbn)) == NULL || 879 (tbp->b_vflags & BV_BKGRDINPROG)) { 880 BO_UNLOCK(bo); 881 break; 882 } 883 884 /* 885 * If it IS in core, but has different 886 * characteristics, or is locked (which 887 * means it could be undergoing a background 888 * I/O or be in a weird state), then don't 889 * cluster with it. 890 */ 891 if (BUF_LOCK(tbp, 892 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 893 BO_LOCKPTR(bo))) 894 break; 895 896 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 897 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 898 != (B_DELWRI | B_CLUSTEROK | 899 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 900 tbp->b_wcred != bp->b_wcred) { 901 BUF_UNLOCK(tbp); 902 break; 903 } 904 905 /* 906 * Check that the combined cluster 907 * would make sense with regard to pages 908 * and would not be too large 909 */ 910 if ((tbp->b_bcount != size) || 911 ((bp->b_blkno + (dbsize * i)) != 912 tbp->b_blkno) || 913 ((tbp->b_npages + bp->b_npages) > 914 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 915 BUF_UNLOCK(tbp); 916 break; 917 } 918 919 /* 920 * Do not pull in pinned buffers. 921 */ 922 if (tbp->b_pin_count > 0) { 923 BUF_UNLOCK(tbp); 924 break; 925 } 926 927 /* 928 * Ok, it's passed all the tests, 929 * so remove it from the free list 930 * and mark it busy. We will use it. 931 */ 932 bremfree(tbp); 933 tbp->b_flags &= ~B_DONE; 934 } /* end of code for non-first buffers only */ 935 /* 936 * If the IO is via the VM then we do some 937 * special VM hackery (yuck). Since the buffer's 938 * block size may not be page-aligned it is possible 939 * for a page to be shared between two buffers. We 940 * have to get rid of the duplication when building 941 * the cluster. 942 */ 943 if (tbp->b_flags & B_VMIO) { 944 vm_page_t m; 945 946 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 947 if (i != 0) { /* if not first buffer */ 948 for (j = 0; j < tbp->b_npages; j += 1) { 949 m = tbp->b_pages[j]; 950 if (m->oflags & VPO_BUSY) { 951 VM_OBJECT_WUNLOCK( 952 tbp->b_object); 953 bqrelse(tbp); 954 goto finishcluster; 955 } 956 } 957 } 958 for (j = 0; j < tbp->b_npages; j += 1) { 959 m = tbp->b_pages[j]; 960 vm_page_io_start(m); 961 vm_object_pip_add(m->object, 1); 962 if ((bp->b_npages == 0) || 963 (bp->b_pages[bp->b_npages - 1] != m)) { 964 bp->b_pages[bp->b_npages] = m; 965 bp->b_npages++; 966 } 967 } 968 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 969 } 970 bp->b_bcount += size; 971 bp->b_bufsize += size; 972 /* 973 * If any of the clustered buffers have their 974 * B_BARRIER flag set, transfer that request to 975 * the cluster. 976 */ 977 bp->b_flags |= (tbp->b_flags & B_BARRIER); 978 tbp->b_flags &= ~(B_DONE | B_BARRIER); 979 tbp->b_flags |= B_ASYNC; 980 tbp->b_ioflags &= ~BIO_ERROR; 981 tbp->b_iocmd = BIO_WRITE; 982 bundirty(tbp); 983 reassignbuf(tbp); /* put on clean list */ 984 bufobj_wref(tbp->b_bufobj); 985 BUF_KERNPROC(tbp); 986 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 987 tbp, b_cluster.cluster_entry); 988 } 989 finishcluster: 990 if ((bp->b_flags & B_UNMAPPED) == 0) { 991 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 992 (vm_page_t *)bp->b_pages, bp->b_npages); 993 } 994 if (bp->b_bufsize > bp->b_kvasize) 995 panic( 996 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 997 bp->b_bufsize, bp->b_kvasize); 998 bp->b_kvasize = bp->b_bufsize; 999 totalwritten += bp->b_bufsize; 1000 bp->b_dirtyoff = 0; 1001 bp->b_dirtyend = bp->b_bufsize; 1002 bawrite(bp); 1003 1004 len -= i; 1005 } 1006 return totalwritten; 1007 } 1008 1009 /* 1010 * Collect together all the buffers in a cluster. 1011 * Plus add one additional buffer. 1012 */ 1013 static struct cluster_save * 1014 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int gbflags) 1015 { 1016 struct cluster_save *buflist; 1017 struct buf *bp; 1018 daddr_t lbn; 1019 int i, len; 1020 1021 len = vp->v_lastw - vp->v_cstart + 1; 1022 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 1023 M_SEGMENT, M_WAITOK); 1024 buflist->bs_nchildren = 0; 1025 buflist->bs_children = (struct buf **) (buflist + 1); 1026 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 1027 (void)bread_gb(vp, lbn, last_bp->b_bcount, NOCRED, 1028 gbflags, &bp); 1029 buflist->bs_children[i] = bp; 1030 if (bp->b_blkno == bp->b_lblkno) 1031 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 1032 NULL, NULL); 1033 } 1034 buflist->bs_children[i] = bp = last_bp; 1035 if (bp->b_blkno == bp->b_lblkno) 1036 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1037 buflist->bs_nchildren = i + 1; 1038 return (buflist); 1039 } 1040