1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * Modifications/enhancements: 7 * Copyright (c) 1995 John S. Dyson. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/proc.h> 38 #include <sys/bio.h> 39 #include <sys/buf.h> 40 #include <sys/vnode.h> 41 #include <sys/malloc.h> 42 #include <sys/mount.h> 43 #include <sys/racct.h> 44 #include <sys/resourcevar.h> 45 #include <sys/rwlock.h> 46 #include <sys/vmmeter.h> 47 #include <vm/vm.h> 48 #include <vm/vm_object.h> 49 #include <vm/vm_page.h> 50 #include <sys/sysctl.h> 51 52 static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer"); 53 static uma_zone_t cluster_pbuf_zone; 54 55 static void cluster_init(void *); 56 static struct cluster_save *cluster_collectbufs(struct vnode *vp, 57 struct vn_clusterw *vnc, struct buf *last_bp, int gbflags); 58 static struct buf *cluster_rbuild(struct vnode *vp, u_quad_t filesize, 59 daddr_t lbn, daddr_t blkno, long size, int run, int gbflags, 60 struct buf *fbp); 61 static void cluster_callback(struct buf *); 62 63 static int write_behind = 1; 64 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 65 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 66 67 static int read_max = 64; 68 SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 69 "Cluster read-ahead max block count"); 70 71 static int read_min = 1; 72 SYSCTL_INT(_vfs, OID_AUTO, read_min, CTLFLAG_RW, &read_min, 0, 73 "Cluster read min block count"); 74 75 SYSINIT(cluster, SI_SUB_CPU, SI_ORDER_ANY, cluster_init, NULL); 76 77 static void 78 cluster_init(void *dummy) 79 { 80 81 cluster_pbuf_zone = pbuf_zsecond_create("clpbuf", nswbuf / 2); 82 } 83 84 /* 85 * Read data to a buf, including read-ahead if we find this to be beneficial. 86 * cluster_read replaces bread. 87 */ 88 int 89 cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, long size, 90 struct ucred *cred, long totread, int seqcount, int gbflags, 91 struct buf **bpp) 92 { 93 struct buf *bp, *rbp, *reqbp; 94 struct bufobj *bo; 95 struct thread *td; 96 daddr_t blkno, origblkno; 97 int maxra, racluster; 98 int error, ncontig; 99 int i; 100 101 error = 0; 102 td = curthread; 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 error = getblkx(vp, lblkno, lblkno, size, 0, 0, gbflags, &bp); 122 if (error != 0) { 123 *bpp = NULL; 124 return (error); 125 } 126 gbflags &= ~GB_NOSPARSE; 127 origblkno = lblkno; 128 *bpp = reqbp = bp; 129 130 /* 131 * if it is in the cache, then check to see if the reads have been 132 * sequential. If they have, then try some read-ahead, otherwise 133 * back-off on prospective read-aheads. 134 */ 135 if (bp->b_flags & B_CACHE) { 136 if (!seqcount) { 137 return 0; 138 } else if ((bp->b_flags & B_RAM) == 0) { 139 return 0; 140 } else { 141 bp->b_flags &= ~B_RAM; 142 BO_RLOCK(bo); 143 for (i = 1; i < maxra; i++) { 144 /* 145 * Stop if the buffer does not exist or it 146 * is invalid (about to go away?) 147 */ 148 rbp = gbincore(&vp->v_bufobj, lblkno+i); 149 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 150 break; 151 152 /* 153 * Set another read-ahead mark so we know 154 * to check again. (If we can lock the 155 * buffer without waiting) 156 */ 157 if ((((i % racluster) == (racluster - 1)) || 158 (i == (maxra - 1))) 159 && (0 == BUF_LOCK(rbp, 160 LK_EXCLUSIVE | LK_NOWAIT, NULL))) { 161 rbp->b_flags |= B_RAM; 162 BUF_UNLOCK(rbp); 163 } 164 } 165 BO_RUNLOCK(bo); 166 if (i >= maxra) { 167 return 0; 168 } 169 lblkno += i; 170 } 171 reqbp = bp = NULL; 172 /* 173 * If it isn't in the cache, then get a chunk from 174 * disk if sequential, otherwise just get the block. 175 */ 176 } else { 177 off_t firstread = bp->b_offset; 178 int nblks; 179 long minread; 180 181 KASSERT(bp->b_offset != NOOFFSET, 182 ("cluster_read: no buffer offset")); 183 184 ncontig = 0; 185 186 /* 187 * Adjust totread if needed 188 */ 189 minread = read_min * size; 190 if (minread > totread) 191 totread = minread; 192 193 /* 194 * Compute the total number of blocks that we should read 195 * synchronously. 196 */ 197 if (firstread + totread > filesize) 198 totread = filesize - firstread; 199 nblks = howmany(totread, size); 200 if (nblks > racluster) 201 nblks = racluster; 202 203 /* 204 * Now compute the number of contiguous blocks. 205 */ 206 if (nblks > 1) { 207 error = VOP_BMAP(vp, lblkno, NULL, 208 &blkno, &ncontig, NULL); 209 /* 210 * If this failed to map just do the original block. 211 */ 212 if (error || blkno == -1) 213 ncontig = 0; 214 } 215 216 /* 217 * If we have contiguous data available do a cluster 218 * otherwise just read the requested block. 219 */ 220 if (ncontig) { 221 /* Account for our first block. */ 222 ncontig = min(ncontig + 1, nblks); 223 if (ncontig < nblks) 224 nblks = ncontig; 225 bp = cluster_rbuild(vp, filesize, lblkno, 226 blkno, size, nblks, gbflags, bp); 227 lblkno += (bp->b_bufsize / size); 228 } else { 229 bp->b_flags |= B_RAM; 230 bp->b_iocmd = BIO_READ; 231 lblkno += 1; 232 } 233 } 234 235 /* 236 * handle the synchronous read so that it is available ASAP. 237 */ 238 if (bp) { 239 if ((bp->b_flags & B_CLUSTER) == 0) { 240 vfs_busy_pages(bp, 0); 241 } 242 bp->b_flags &= ~B_INVAL; 243 bp->b_ioflags &= ~BIO_ERROR; 244 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 245 BUF_KERNPROC(bp); 246 bp->b_iooffset = dbtob(bp->b_blkno); 247 bstrategy(bp); 248 #ifdef RACCT 249 if (racct_enable) { 250 PROC_LOCK(td->td_proc); 251 racct_add_buf(td->td_proc, bp, 0); 252 PROC_UNLOCK(td->td_proc); 253 } 254 #endif /* RACCT */ 255 td->td_ru.ru_inblock++; 256 } 257 258 /* 259 * If we have been doing sequential I/O, then do some read-ahead. 260 */ 261 while (lblkno < (origblkno + maxra)) { 262 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 263 if (error) { 264 error = 0; 265 break; 266 } 267 268 if (blkno == -1) 269 break; 270 271 /* 272 * We could throttle ncontig here by maxra but we might as 273 * well read the data if it is contiguous. We're throttled 274 * by racluster anyway. 275 */ 276 if (ncontig) { 277 ncontig = min(ncontig + 1, racluster); 278 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 279 size, ncontig, gbflags, NULL); 280 lblkno += (rbp->b_bufsize / size); 281 if (rbp->b_flags & B_DELWRI) { 282 bqrelse(rbp); 283 continue; 284 } 285 } else { 286 rbp = getblk(vp, lblkno, size, 0, 0, gbflags); 287 lblkno += 1; 288 if (rbp->b_flags & B_DELWRI) { 289 bqrelse(rbp); 290 continue; 291 } 292 rbp->b_flags |= B_ASYNC | B_RAM; 293 rbp->b_iocmd = BIO_READ; 294 rbp->b_blkno = blkno; 295 } 296 if (rbp->b_flags & B_CACHE) { 297 rbp->b_flags &= ~B_ASYNC; 298 bqrelse(rbp); 299 continue; 300 } 301 if ((rbp->b_flags & B_CLUSTER) == 0) { 302 vfs_busy_pages(rbp, 0); 303 } 304 rbp->b_flags &= ~B_INVAL; 305 rbp->b_ioflags &= ~BIO_ERROR; 306 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 307 BUF_KERNPROC(rbp); 308 rbp->b_iooffset = dbtob(rbp->b_blkno); 309 bstrategy(rbp); 310 #ifdef RACCT 311 if (racct_enable) { 312 PROC_LOCK(td->td_proc); 313 racct_add_buf(td->td_proc, rbp, 0); 314 PROC_UNLOCK(td->td_proc); 315 } 316 #endif /* RACCT */ 317 td->td_ru.ru_inblock++; 318 } 319 320 if (reqbp) { 321 /* 322 * Like bread, always brelse() the buffer when 323 * returning an error. 324 */ 325 error = bufwait(reqbp); 326 if (error != 0) { 327 brelse(reqbp); 328 *bpp = NULL; 329 } 330 } 331 return (error); 332 } 333 334 /* 335 * If blocks are contiguous on disk, use this to provide clustered 336 * read ahead. We will read as many blocks as possible sequentially 337 * and then parcel them up into logical blocks in the buffer hash table. 338 */ 339 static struct buf * 340 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 341 daddr_t blkno, long size, int run, int gbflags, struct buf *fbp) 342 { 343 struct buf *bp, *tbp; 344 daddr_t bn; 345 off_t off; 346 long tinc, tsize; 347 int i, inc, j, k, toff; 348 349 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 350 ("cluster_rbuild: size %ld != f_iosize %jd\n", 351 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 352 353 /* 354 * avoid a division 355 */ 356 while ((u_quad_t) size * (lbn + run) > filesize) { 357 --run; 358 } 359 360 if (fbp) { 361 tbp = fbp; 362 tbp->b_iocmd = BIO_READ; 363 } else { 364 tbp = getblk(vp, lbn, size, 0, 0, gbflags); 365 if (tbp->b_flags & B_CACHE) 366 return tbp; 367 tbp->b_flags |= B_ASYNC | B_RAM; 368 tbp->b_iocmd = BIO_READ; 369 } 370 tbp->b_blkno = blkno; 371 if ( (tbp->b_flags & B_MALLOC) || 372 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 373 return tbp; 374 375 bp = uma_zalloc(cluster_pbuf_zone, M_NOWAIT); 376 if (bp == NULL) 377 return tbp; 378 MPASS((bp->b_flags & B_MAXPHYS) != 0); 379 380 /* 381 * We are synthesizing a buffer out of vm_page_t's, but 382 * if the block size is not page aligned then the starting 383 * address may not be either. Inherit the b_data offset 384 * from the original buffer. 385 */ 386 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 387 if ((gbflags & GB_UNMAPPED) != 0) { 388 bp->b_data = unmapped_buf; 389 } else { 390 bp->b_data = (char *)((vm_offset_t)bp->b_data | 391 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 392 } 393 bp->b_iocmd = BIO_READ; 394 bp->b_iodone = cluster_callback; 395 bp->b_blkno = blkno; 396 bp->b_lblkno = lbn; 397 bp->b_offset = tbp->b_offset; 398 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 399 pbgetvp(vp, bp); 400 401 TAILQ_INIT(&bp->b_cluster.cluster_head); 402 403 bp->b_bcount = 0; 404 bp->b_bufsize = 0; 405 bp->b_npages = 0; 406 407 inc = btodb(size); 408 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 409 if (i == 0) { 410 vm_object_pip_add(tbp->b_bufobj->bo_object, 411 tbp->b_npages); 412 vfs_busy_pages_acquire(tbp); 413 } else { 414 if ((bp->b_npages * PAGE_SIZE) + 415 round_page(size) > vp->v_mount->mnt_iosize_max) { 416 break; 417 } 418 419 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT | 420 (gbflags & GB_UNMAPPED)); 421 422 /* Don't wait around for locked bufs. */ 423 if (tbp == NULL) 424 break; 425 426 /* 427 * Stop scanning if the buffer is fully valid 428 * (marked B_CACHE), or locked (may be doing a 429 * background write), or if the buffer is not 430 * VMIO backed. The clustering code can only deal 431 * with VMIO-backed buffers. The bo lock is not 432 * required for the BKGRDINPROG check since it 433 * can not be set without the buf lock. 434 */ 435 if ((tbp->b_vflags & BV_BKGRDINPROG) || 436 (tbp->b_flags & B_CACHE) || 437 (tbp->b_flags & B_VMIO) == 0) { 438 bqrelse(tbp); 439 break; 440 } 441 442 /* 443 * The buffer must be completely invalid in order to 444 * take part in the cluster. If it is partially valid 445 * then we stop. 446 */ 447 off = tbp->b_offset; 448 tsize = size; 449 for (j = 0; tsize > 0; j++) { 450 toff = off & PAGE_MASK; 451 tinc = tsize; 452 if (toff + tinc > PAGE_SIZE) 453 tinc = PAGE_SIZE - toff; 454 if (vm_page_trysbusy(tbp->b_pages[j]) == 0) 455 break; 456 if ((tbp->b_pages[j]->valid & 457 vm_page_bits(toff, tinc)) != 0) { 458 vm_page_sunbusy(tbp->b_pages[j]); 459 break; 460 } 461 vm_object_pip_add(tbp->b_bufobj->bo_object, 1); 462 off += tinc; 463 tsize -= tinc; 464 } 465 if (tsize > 0) { 466 clean_sbusy: 467 vm_object_pip_wakeupn(tbp->b_bufobj->bo_object, 468 j); 469 for (k = 0; k < j; k++) 470 vm_page_sunbusy(tbp->b_pages[k]); 471 bqrelse(tbp); 472 break; 473 } 474 475 /* 476 * Set a read-ahead mark as appropriate 477 */ 478 if ((fbp && (i == 1)) || (i == (run - 1))) 479 tbp->b_flags |= B_RAM; 480 481 /* 482 * Set the buffer up for an async read (XXX should 483 * we do this only if we do not wind up brelse()ing?). 484 * Set the block number if it isn't set, otherwise 485 * if it is make sure it matches the block number we 486 * expect. 487 */ 488 tbp->b_flags |= B_ASYNC; 489 tbp->b_iocmd = BIO_READ; 490 if (tbp->b_blkno == tbp->b_lblkno) { 491 tbp->b_blkno = bn; 492 } else if (tbp->b_blkno != bn) { 493 goto clean_sbusy; 494 } 495 } 496 /* 497 * XXX fbp from caller may not be B_ASYNC, but we are going 498 * to biodone() it in cluster_callback() anyway 499 */ 500 BUF_KERNPROC(tbp); 501 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 502 tbp, b_cluster.cluster_entry); 503 for (j = 0; j < tbp->b_npages; j += 1) { 504 vm_page_t m; 505 506 m = tbp->b_pages[j]; 507 if ((bp->b_npages == 0) || 508 (bp->b_pages[bp->b_npages-1] != m)) { 509 bp->b_pages[bp->b_npages] = m; 510 bp->b_npages++; 511 } 512 if (vm_page_all_valid(m)) 513 tbp->b_pages[j] = bogus_page; 514 } 515 516 /* 517 * Don't inherit tbp->b_bufsize as it may be larger due to 518 * a non-page-aligned size. Instead just aggregate using 519 * 'size'. 520 */ 521 if (tbp->b_bcount != size) 522 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 523 if (tbp->b_bufsize != size) 524 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 525 bp->b_bcount += size; 526 bp->b_bufsize += size; 527 } 528 529 /* 530 * Fully valid pages in the cluster are already good and do not need 531 * to be re-read from disk. Replace the page with bogus_page 532 */ 533 for (j = 0; j < bp->b_npages; j++) { 534 if (vm_page_all_valid(bp->b_pages[j])) 535 bp->b_pages[j] = bogus_page; 536 } 537 if (bp->b_bufsize > bp->b_kvasize) 538 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 539 bp->b_bufsize, bp->b_kvasize); 540 541 if (buf_mapped(bp)) { 542 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 543 (vm_page_t *)bp->b_pages, bp->b_npages); 544 } 545 return (bp); 546 } 547 548 /* 549 * Cleanup after a clustered read or write. 550 * This is complicated by the fact that any of the buffers might have 551 * extra memory (if there were no empty buffer headers at allocbuf time) 552 * that we will need to shift around. 553 */ 554 static void 555 cluster_callback(struct buf *bp) 556 { 557 struct buf *nbp, *tbp; 558 int error = 0; 559 560 /* 561 * Must propagate errors to all the components. 562 */ 563 if (bp->b_ioflags & BIO_ERROR) 564 error = bp->b_error; 565 566 if (buf_mapped(bp)) { 567 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), 568 bp->b_npages); 569 } 570 /* 571 * Move memory from the large cluster buffer into the component 572 * buffers and mark IO as done on these. 573 */ 574 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 575 tbp; tbp = nbp) { 576 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 577 if (error) { 578 tbp->b_ioflags |= BIO_ERROR; 579 tbp->b_error = error; 580 } else { 581 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 582 tbp->b_flags &= ~B_INVAL; 583 tbp->b_ioflags &= ~BIO_ERROR; 584 /* 585 * XXX the bdwrite()/bqrelse() issued during 586 * cluster building clears B_RELBUF (see bqrelse() 587 * comment). If direct I/O was specified, we have 588 * to restore it here to allow the buffer and VM 589 * to be freed. 590 */ 591 if (tbp->b_flags & B_DIRECT) 592 tbp->b_flags |= B_RELBUF; 593 } 594 bufdone(tbp); 595 } 596 pbrelvp(bp); 597 uma_zfree(cluster_pbuf_zone, bp); 598 } 599 600 /* 601 * cluster_wbuild_wb: 602 * 603 * Implement modified write build for cluster. 604 * 605 * write_behind = 0 write behind disabled 606 * write_behind = 1 write behind normal (default) 607 * write_behind = 2 write behind backed-off 608 */ 609 610 static __inline int 611 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len, 612 int gbflags) 613 { 614 int r = 0; 615 616 switch (write_behind) { 617 case 2: 618 if (start_lbn < len) 619 break; 620 start_lbn -= len; 621 /* FALLTHROUGH */ 622 case 1: 623 r = cluster_wbuild(vp, size, start_lbn, len, gbflags); 624 /* FALLTHROUGH */ 625 default: 626 /* FALLTHROUGH */ 627 break; 628 } 629 return(r); 630 } 631 632 /* 633 * Do clustered write for FFS. 634 * 635 * Three cases: 636 * 1. Write is not sequential (write asynchronously) 637 * Write is sequential: 638 * 2. beginning of cluster - begin cluster 639 * 3. middle of a cluster - add to cluster 640 * 4. end of a cluster - asynchronously write cluster 641 */ 642 void 643 cluster_write(struct vnode *vp, struct vn_clusterw *vnc, struct buf *bp, 644 u_quad_t filesize, int seqcount, int gbflags) 645 { 646 daddr_t lbn, pbn; 647 int maxclen, cursize; 648 int lblocksize; 649 int async; 650 651 if (!unmapped_buf_allowed) 652 gbflags &= ~GB_UNMAPPED; 653 654 if (vp->v_type == VREG) { 655 async = DOINGASYNC(vp); 656 lblocksize = vp->v_mount->mnt_stat.f_iosize; 657 } else { 658 async = 0; 659 lblocksize = bp->b_bufsize; 660 } 661 lbn = bp->b_lblkno; 662 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 663 664 /* Initialize vnode to beginning of file. */ 665 if (lbn == 0) 666 vnc->v_lasta = vnc->v_clen = vnc->v_cstart = vnc->v_lastw = 0; 667 668 if (vnc->v_clen == 0 || lbn != vnc->v_lastw + 1 || 669 (bp->b_blkno != vnc->v_lasta + btodb(lblocksize))) { 670 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 671 if (vnc->v_clen != 0) { 672 /* 673 * Next block is not sequential. 674 * 675 * If we are not writing at end of file, the process 676 * seeked to another point in the file since its last 677 * write, or we have reached our maximum cluster size, 678 * then push the previous cluster. Otherwise try 679 * reallocating to make it sequential. 680 * 681 * Change to algorithm: only push previous cluster if 682 * it was sequential from the point of view of the 683 * seqcount heuristic, otherwise leave the buffer 684 * intact so we can potentially optimize the I/O 685 * later on in the buf_daemon or update daemon 686 * flush. 687 */ 688 cursize = vnc->v_lastw - vnc->v_cstart + 1; 689 if ((u_quad_t)bp->b_offset + lblocksize != filesize || 690 lbn != vnc->v_lastw + 1 || vnc->v_clen <= cursize) { 691 if (!async && seqcount > 0) { 692 cluster_wbuild_wb(vp, lblocksize, 693 vnc->v_cstart, cursize, gbflags); 694 } 695 } else { 696 struct buf **bpp, **endbp; 697 struct cluster_save *buflist; 698 699 buflist = cluster_collectbufs(vp, vnc, bp, 700 gbflags); 701 if (buflist == NULL) { 702 /* 703 * Cluster build failed so just write 704 * it now. 705 */ 706 bawrite(bp); 707 return; 708 } 709 endbp = &buflist->bs_children 710 [buflist->bs_nchildren - 1]; 711 if (VOP_REALLOCBLKS(vp, buflist)) { 712 /* 713 * Failed, push the previous cluster 714 * if *really* writing sequentially 715 * in the logical file (seqcount > 1), 716 * otherwise delay it in the hopes that 717 * the low level disk driver can 718 * optimize the write ordering. 719 */ 720 for (bpp = buflist->bs_children; 721 bpp < endbp; bpp++) 722 brelse(*bpp); 723 free(buflist, M_SEGMENT); 724 if (seqcount > 1) { 725 cluster_wbuild_wb(vp, 726 lblocksize, vnc->v_cstart, 727 cursize, gbflags); 728 } 729 } else { 730 /* 731 * Succeeded, keep building cluster. 732 */ 733 for (bpp = buflist->bs_children; 734 bpp <= endbp; bpp++) 735 bdwrite(*bpp); 736 free(buflist, M_SEGMENT); 737 vnc->v_lastw = lbn; 738 vnc->v_lasta = bp->b_blkno; 739 return; 740 } 741 } 742 } 743 /* 744 * Consider beginning a cluster. If at end of file, make 745 * cluster as large as possible, otherwise find size of 746 * existing cluster. 747 */ 748 if (vp->v_type == VREG && 749 (u_quad_t) bp->b_offset + lblocksize != filesize && 750 bp->b_blkno == bp->b_lblkno && 751 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, 752 NULL) != 0 || bp->b_blkno == -1)) { 753 pbn = bp->b_blkno; 754 bawrite(bp); 755 vnc->v_clen = 0; 756 vnc->v_lasta = pbn; 757 vnc->v_cstart = lbn + 1; 758 vnc->v_lastw = lbn; 759 return; 760 } 761 vnc->v_clen = maxclen; 762 pbn = bp->b_blkno; 763 if (!async && maxclen == 0) { /* I/O not contiguous */ 764 vnc->v_cstart = lbn + 1; 765 bawrite(bp); 766 } else { /* Wait for rest of cluster */ 767 vnc->v_cstart = lbn; 768 bdwrite(bp); 769 } 770 } else if (lbn == vnc->v_cstart + vnc->v_clen) { 771 /* 772 * At end of cluster, write it out if seqcount tells us we 773 * are operating sequentially, otherwise let the buf or 774 * update daemon handle it. 775 */ 776 pbn = bp->b_blkno; 777 bdwrite(bp); 778 if (seqcount > 1) { 779 cluster_wbuild_wb(vp, lblocksize, vnc->v_cstart, 780 vnc->v_clen + 1, gbflags); 781 } 782 vnc->v_clen = 0; 783 vnc->v_cstart = lbn + 1; 784 } else if (vm_page_count_severe()) { 785 /* 786 * We are low on memory, get it going NOW 787 */ 788 pbn = bp->b_blkno; 789 bawrite(bp); 790 } else { 791 /* 792 * In the middle of a cluster, so just delay the I/O for now. 793 */ 794 pbn = bp->b_blkno; 795 bdwrite(bp); 796 } 797 vnc->v_lastw = lbn; 798 vnc->v_lasta = pbn; 799 } 800 801 /* 802 * This is an awful lot like cluster_rbuild...wish they could be combined. 803 * The last lbn argument is the current block on which I/O is being 804 * performed. Check to see that it doesn't fall in the middle of 805 * the current block (if last_bp == NULL). 806 */ 807 int 808 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len, 809 int gbflags) 810 { 811 struct buf *bp, *tbp; 812 struct bufobj *bo; 813 int i, j; 814 int totalwritten = 0; 815 int dbsize = btodb(size); 816 817 if (!unmapped_buf_allowed) 818 gbflags &= ~GB_UNMAPPED; 819 820 bo = &vp->v_bufobj; 821 while (len > 0) { 822 /* 823 * If the buffer is not delayed-write (i.e. dirty), or it 824 * is delayed-write but either locked or inval, it cannot 825 * partake in the clustered write. 826 */ 827 BO_LOCK(bo); 828 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 829 (tbp->b_vflags & BV_BKGRDINPROG)) { 830 BO_UNLOCK(bo); 831 ++start_lbn; 832 --len; 833 continue; 834 } 835 if (BUF_LOCK(tbp, 836 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_LOCKPTR(bo))) { 837 ++start_lbn; 838 --len; 839 continue; 840 } 841 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 842 BUF_UNLOCK(tbp); 843 ++start_lbn; 844 --len; 845 continue; 846 } 847 bremfree(tbp); 848 tbp->b_flags &= ~B_DONE; 849 850 /* 851 * Extra memory in the buffer, punt on this buffer. 852 * XXX we could handle this in most cases, but we would 853 * have to push the extra memory down to after our max 854 * possible cluster size and then potentially pull it back 855 * up if the cluster was terminated prematurely--too much 856 * hassle. 857 */ 858 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 859 (B_CLUSTEROK | B_VMIO)) || 860 (tbp->b_bcount != tbp->b_bufsize) || 861 (tbp->b_bcount != size) || 862 (len == 1) || 863 ((bp = uma_zalloc(cluster_pbuf_zone, M_NOWAIT)) == NULL)) { 864 totalwritten += tbp->b_bufsize; 865 bawrite(tbp); 866 ++start_lbn; 867 --len; 868 continue; 869 } 870 MPASS((bp->b_flags & B_MAXPHYS) != 0); 871 872 /* 873 * We got a pbuf to make the cluster in. 874 * so initialise it. 875 */ 876 TAILQ_INIT(&bp->b_cluster.cluster_head); 877 bp->b_bcount = 0; 878 bp->b_bufsize = 0; 879 bp->b_npages = 0; 880 if (tbp->b_wcred != NOCRED) 881 bp->b_wcred = crhold(tbp->b_wcred); 882 883 bp->b_blkno = tbp->b_blkno; 884 bp->b_lblkno = tbp->b_lblkno; 885 bp->b_offset = tbp->b_offset; 886 887 /* 888 * We are synthesizing a buffer out of vm_page_t's, but 889 * if the block size is not page aligned then the starting 890 * address may not be either. Inherit the b_data offset 891 * from the original buffer. 892 */ 893 if ((gbflags & GB_UNMAPPED) == 0 || 894 (tbp->b_flags & B_VMIO) == 0) { 895 bp->b_data = (char *)((vm_offset_t)bp->b_data | 896 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 897 } else { 898 bp->b_data = unmapped_buf; 899 } 900 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO | 901 B_NEEDCOMMIT)); 902 bp->b_iodone = cluster_callback; 903 pbgetvp(vp, bp); 904 /* 905 * From this location in the file, scan forward to see 906 * if there are buffers with adjacent data that need to 907 * be written as well. 908 */ 909 for (i = 0; i < len; ++i, ++start_lbn) { 910 if (i != 0) { /* If not the first buffer */ 911 /* 912 * If the adjacent data is not even in core it 913 * can't need to be written. 914 */ 915 BO_LOCK(bo); 916 if ((tbp = gbincore(bo, start_lbn)) == NULL || 917 (tbp->b_vflags & BV_BKGRDINPROG)) { 918 BO_UNLOCK(bo); 919 break; 920 } 921 922 /* 923 * If it IS in core, but has different 924 * characteristics, or is locked (which 925 * means it could be undergoing a background 926 * I/O or be in a weird state), then don't 927 * cluster with it. 928 */ 929 if (BUF_LOCK(tbp, 930 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 931 BO_LOCKPTR(bo))) 932 break; 933 934 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 935 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 936 != (B_DELWRI | B_CLUSTEROK | 937 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 938 tbp->b_wcred != bp->b_wcred) { 939 BUF_UNLOCK(tbp); 940 break; 941 } 942 943 /* 944 * Check that the combined cluster 945 * would make sense with regard to pages 946 * and would not be too large 947 */ 948 if ((tbp->b_bcount != size) || 949 ((bp->b_blkno + (dbsize * i)) != 950 tbp->b_blkno) || 951 ((tbp->b_npages + bp->b_npages) > 952 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 953 BUF_UNLOCK(tbp); 954 break; 955 } 956 957 /* 958 * Ok, it's passed all the tests, 959 * so remove it from the free list 960 * and mark it busy. We will use it. 961 */ 962 bremfree(tbp); 963 tbp->b_flags &= ~B_DONE; 964 } /* end of code for non-first buffers only */ 965 /* 966 * If the IO is via the VM then we do some 967 * special VM hackery (yuck). Since the buffer's 968 * block size may not be page-aligned it is possible 969 * for a page to be shared between two buffers. We 970 * have to get rid of the duplication when building 971 * the cluster. 972 */ 973 if (tbp->b_flags & B_VMIO) { 974 vm_page_t m; 975 976 if (i == 0) { 977 vfs_busy_pages_acquire(tbp); 978 } else { /* if not first buffer */ 979 for (j = 0; j < tbp->b_npages; j += 1) { 980 m = tbp->b_pages[j]; 981 if (vm_page_trysbusy(m) == 0) { 982 for (j--; j >= 0; j--) 983 vm_page_sunbusy( 984 tbp->b_pages[j]); 985 bqrelse(tbp); 986 goto finishcluster; 987 } 988 } 989 } 990 vm_object_pip_add(tbp->b_bufobj->bo_object, 991 tbp->b_npages); 992 for (j = 0; j < tbp->b_npages; j += 1) { 993 m = tbp->b_pages[j]; 994 if ((bp->b_npages == 0) || 995 (bp->b_pages[bp->b_npages - 1] != m)) { 996 bp->b_pages[bp->b_npages] = m; 997 bp->b_npages++; 998 } 999 } 1000 } 1001 bp->b_bcount += size; 1002 bp->b_bufsize += size; 1003 /* 1004 * If any of the clustered buffers have their 1005 * B_BARRIER flag set, transfer that request to 1006 * the cluster. 1007 */ 1008 bp->b_flags |= (tbp->b_flags & B_BARRIER); 1009 tbp->b_flags &= ~(B_DONE | B_BARRIER); 1010 tbp->b_flags |= B_ASYNC; 1011 tbp->b_ioflags &= ~BIO_ERROR; 1012 tbp->b_iocmd = BIO_WRITE; 1013 bundirty(tbp); 1014 reassignbuf(tbp); /* put on clean list */ 1015 bufobj_wref(tbp->b_bufobj); 1016 BUF_KERNPROC(tbp); 1017 buf_track(tbp, __func__); 1018 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 1019 tbp, b_cluster.cluster_entry); 1020 } 1021 finishcluster: 1022 if (buf_mapped(bp)) { 1023 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 1024 (vm_page_t *)bp->b_pages, bp->b_npages); 1025 } 1026 if (bp->b_bufsize > bp->b_kvasize) 1027 panic( 1028 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 1029 bp->b_bufsize, bp->b_kvasize); 1030 totalwritten += bp->b_bufsize; 1031 bp->b_dirtyoff = 0; 1032 bp->b_dirtyend = bp->b_bufsize; 1033 bawrite(bp); 1034 1035 len -= i; 1036 } 1037 return totalwritten; 1038 } 1039 1040 /* 1041 * Collect together all the buffers in a cluster. 1042 * Plus add one additional buffer. 1043 */ 1044 static struct cluster_save * 1045 cluster_collectbufs(struct vnode *vp, struct vn_clusterw *vnc, 1046 struct buf *last_bp, int gbflags) 1047 { 1048 struct cluster_save *buflist; 1049 struct buf *bp; 1050 daddr_t lbn; 1051 int i, j, len, error; 1052 1053 len = vnc->v_lastw - vnc->v_cstart + 1; 1054 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 1055 M_SEGMENT, M_WAITOK); 1056 buflist->bs_nchildren = 0; 1057 buflist->bs_children = (struct buf **) (buflist + 1); 1058 for (lbn = vnc->v_cstart, i = 0; i < len; lbn++, i++) { 1059 error = bread_gb(vp, lbn, last_bp->b_bcount, NOCRED, 1060 gbflags, &bp); 1061 if (error != 0) { 1062 /* 1063 * If read fails, release collected buffers 1064 * and return failure. 1065 */ 1066 for (j = 0; j < i; j++) 1067 brelse(buflist->bs_children[j]); 1068 free(buflist, M_SEGMENT); 1069 return (NULL); 1070 } 1071 buflist->bs_children[i] = bp; 1072 if (bp->b_blkno == bp->b_lblkno) 1073 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 1074 NULL, NULL); 1075 } 1076 buflist->bs_children[i] = bp = last_bp; 1077 if (bp->b_blkno == bp->b_lblkno) 1078 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1079 buflist->bs_nchildren = i + 1; 1080 return (buflist); 1081 } 1082 1083 void 1084 cluster_init_vn(struct vn_clusterw *vnc) 1085 { 1086 vnc->v_lasta = 0; 1087 vnc->v_clen = 0; 1088 vnc->v_cstart = 0; 1089 vnc->v_lastw = 0; 1090 } 1091