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: stable/11/sys/kern/vfs_cluster.c 352947 2019-10-01 23:28:22Z mckusick $"); 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/racct.h> 49#include <sys/resourcevar.h> 50#include <sys/rwlock.h> 51#include <sys/vmmeter.h> 52#include <vm/vm.h> 53#include <vm/vm_object.h> 54#include <vm/vm_page.h> 55#include <sys/sysctl.h> 56 57#if defined(CLUSTERDEBUG) 58static int rcluster= 0; 59SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, 60 "Debug VFS clustering code"); 61#endif 62 63static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer"); 64 65static struct cluster_save *cluster_collectbufs(struct vnode *vp, 66 struct buf *last_bp, int gbflags); 67static struct buf *cluster_rbuild(struct vnode *vp, u_quad_t filesize, 68 daddr_t lbn, daddr_t blkno, long size, int run, int gbflags, 69 struct buf *fbp); 70static void cluster_callback(struct buf *); 71 72static int write_behind = 1; 73SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, 74 "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); 75 76static int read_max = 64; 77SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, 78 "Cluster read-ahead max block count"); 79 80static int read_min = 1; 81SYSCTL_INT(_vfs, OID_AUTO, read_min, CTLFLAG_RW, &read_min, 0, 82 "Cluster read min block count"); 83 84/* Page expended to mark partially backed buffers */ 85extern vm_page_t bogus_page; 86 87/* 88 * Read data to a buf, including read-ahead if we find this to be beneficial. 89 * cluster_read replaces bread. 90 */ 91int 92cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, long size, 93 struct ucred *cred, long totread, int seqcount, int gbflags, 94 struct buf **bpp) 95{ 96 struct buf *bp, *rbp, *reqbp; 97 struct bufobj *bo; 98 daddr_t blkno, origblkno; 99 int maxra, racluster; 100 int error, ncontig; 101 int i; 102 103 error = 0; 104 bo = &vp->v_bufobj; 105 if (!unmapped_buf_allowed) 106 gbflags &= ~GB_UNMAPPED; 107 108 /* 109 * Try to limit the amount of read-ahead by a few 110 * ad-hoc parameters. This needs work!!! 111 */ 112 racluster = vp->v_mount->mnt_iosize_max / size; 113 maxra = seqcount; 114 maxra = min(read_max, maxra); 115 maxra = min(nbuf/8, maxra); 116 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 117 maxra = (filesize / size) - lblkno; 118 119 /* 120 * get the requested block 121 */ 122 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, gbflags); 123 if (bp == NULL) 124 return (EBUSY); 125 origblkno = lblkno; 126 127 /* 128 * if it is in the cache, then check to see if the reads have been 129 * sequential. If they have, then try some read-ahead, otherwise 130 * back-off on prospective read-aheads. 131 */ 132 if (bp->b_flags & B_CACHE) { 133 if (!seqcount) { 134 return 0; 135 } else if ((bp->b_flags & B_RAM) == 0) { 136 return 0; 137 } else { 138 bp->b_flags &= ~B_RAM; 139 BO_RLOCK(bo); 140 for (i = 1; i < maxra; i++) { 141 /* 142 * Stop if the buffer does not exist or it 143 * is invalid (about to go away?) 144 */ 145 rbp = gbincore(&vp->v_bufobj, lblkno+i); 146 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 147 break; 148 149 /* 150 * Set another read-ahead mark so we know 151 * to check again. (If we can lock the 152 * buffer without waiting) 153 */ 154 if ((((i % racluster) == (racluster - 1)) || 155 (i == (maxra - 1))) 156 && (0 == BUF_LOCK(rbp, 157 LK_EXCLUSIVE | LK_NOWAIT, NULL))) { 158 rbp->b_flags |= B_RAM; 159 BUF_UNLOCK(rbp); 160 } 161 } 162 BO_RUNLOCK(bo); 163 if (i >= maxra) { 164 return 0; 165 } 166 lblkno += i; 167 } 168 reqbp = bp = NULL; 169 /* 170 * If it isn't in the cache, then get a chunk from 171 * disk if sequential, otherwise just get the block. 172 */ 173 } else { 174 off_t firstread = bp->b_offset; 175 int nblks; 176 long minread; 177 178 KASSERT(bp->b_offset != NOOFFSET, 179 ("cluster_read: no buffer offset")); 180 181 ncontig = 0; 182 183 /* 184 * Adjust totread if needed 185 */ 186 minread = read_min * size; 187 if (minread > totread) 188 totread = minread; 189 190 /* 191 * Compute the total number of blocks that we should read 192 * synchronously. 193 */ 194 if (firstread + totread > filesize) 195 totread = filesize - firstread; 196 nblks = howmany(totread, size); 197 if (nblks > racluster) 198 nblks = racluster; 199 200 /* 201 * Now compute the number of contiguous blocks. 202 */ 203 if (nblks > 1) { 204 error = VOP_BMAP(vp, lblkno, NULL, 205 &blkno, &ncontig, NULL); 206 /* 207 * If this failed to map just do the original block. 208 */ 209 if (error || blkno == -1) 210 ncontig = 0; 211 } 212 213 /* 214 * If we have contiguous data available do a cluster 215 * otherwise just read the requested block. 216 */ 217 if (ncontig) { 218 /* Account for our first block. */ 219 ncontig = min(ncontig + 1, nblks); 220 if (ncontig < nblks) 221 nblks = ncontig; 222 bp = cluster_rbuild(vp, filesize, lblkno, 223 blkno, size, nblks, gbflags, bp); 224 lblkno += (bp->b_bufsize / size); 225 } else { 226 bp->b_flags |= B_RAM; 227 bp->b_iocmd = BIO_READ; 228 lblkno += 1; 229 } 230 } 231 232 /* 233 * handle the synchronous read so that it is available ASAP. 234 */ 235 if (bp) { 236 if ((bp->b_flags & B_CLUSTER) == 0) { 237 vfs_busy_pages(bp, 0); 238 } 239 bp->b_flags &= ~B_INVAL; 240 bp->b_ioflags &= ~BIO_ERROR; 241 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 242 BUF_KERNPROC(bp); 243 bp->b_iooffset = dbtob(bp->b_blkno); 244 bstrategy(bp); 245#ifdef RACCT 246 if (racct_enable) { 247 PROC_LOCK(curproc); 248 racct_add_buf(curproc, bp, 0); 249 PROC_UNLOCK(curproc); 250 } 251#endif /* RACCT */ 252 curthread->td_ru.ru_inblock++; 253 } 254 255 /* 256 * If we have been doing sequential I/O, then do some read-ahead. 257 */ 258 while (lblkno < (origblkno + maxra)) { 259 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 260 if (error) 261 break; 262 263 if (blkno == -1) 264 break; 265 266 /* 267 * We could throttle ncontig here by maxra but we might as 268 * well read the data if it is contiguous. We're throttled 269 * by racluster anyway. 270 */ 271 if (ncontig) { 272 ncontig = min(ncontig + 1, racluster); 273 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 274 size, ncontig, gbflags, NULL); 275 lblkno += (rbp->b_bufsize / size); 276 if (rbp->b_flags & B_DELWRI) { 277 bqrelse(rbp); 278 continue; 279 } 280 } else { 281 rbp = getblk(vp, lblkno, size, 0, 0, gbflags); 282 lblkno += 1; 283 if (rbp->b_flags & B_DELWRI) { 284 bqrelse(rbp); 285 continue; 286 } 287 rbp->b_flags |= B_ASYNC | B_RAM; 288 rbp->b_iocmd = BIO_READ; 289 rbp->b_blkno = blkno; 290 } 291 if (rbp->b_flags & B_CACHE) { 292 rbp->b_flags &= ~B_ASYNC; 293 bqrelse(rbp); 294 continue; 295 } 296 if ((rbp->b_flags & B_CLUSTER) == 0) { 297 vfs_busy_pages(rbp, 0); 298 } 299 rbp->b_flags &= ~B_INVAL; 300 rbp->b_ioflags &= ~BIO_ERROR; 301 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 302 BUF_KERNPROC(rbp); 303 rbp->b_iooffset = dbtob(rbp->b_blkno); 304 bstrategy(rbp); 305#ifdef RACCT 306 if (racct_enable) { 307 PROC_LOCK(curproc); 308 racct_add_buf(curproc, rbp, 0); 309 PROC_UNLOCK(curproc); 310 } 311#endif /* RACCT */ 312 curthread->td_ru.ru_inblock++; 313 } 314 315 if (reqbp) { 316 /* 317 * Like bread, always brelse() the buffer when 318 * returning an error. 319 */ 320 error = bufwait(reqbp); 321 if (error != 0) { 322 brelse(reqbp); 323 *bpp = NULL; 324 } 325 } 326 return (error); 327} 328 329/* 330 * If blocks are contiguous on disk, use this to provide clustered 331 * read ahead. We will read as many blocks as possible sequentially 332 * and then parcel them up into logical blocks in the buffer hash table. 333 */ 334static struct buf * 335cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 336 daddr_t blkno, long size, int run, int gbflags, struct buf *fbp) 337{ 338 struct buf *bp, *tbp; 339 daddr_t bn; 340 off_t off; 341 long tinc, tsize; 342 int i, inc, j, k, toff; 343 344 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 345 ("cluster_rbuild: size %ld != f_iosize %jd\n", 346 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 347 348 /* 349 * avoid a division 350 */ 351 while ((u_quad_t) size * (lbn + run) > filesize) { 352 --run; 353 } 354 355 if (fbp) { 356 tbp = fbp; 357 tbp->b_iocmd = BIO_READ; 358 } else { 359 tbp = getblk(vp, lbn, size, 0, 0, gbflags); 360 if (tbp->b_flags & B_CACHE) 361 return tbp; 362 tbp->b_flags |= B_ASYNC | B_RAM; 363 tbp->b_iocmd = BIO_READ; 364 } 365 tbp->b_blkno = blkno; 366 if( (tbp->b_flags & B_MALLOC) || 367 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 368 return tbp; 369 370 bp = trypbuf(&cluster_pbuf_freecnt); 371 if (bp == NULL) 372 return tbp; 373 374 /* 375 * We are synthesizing a buffer out of vm_page_t's, but 376 * if the block size is not page aligned then the starting 377 * address may not be either. Inherit the b_data offset 378 * from the original buffer. 379 */ 380 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 381 if ((gbflags & GB_UNMAPPED) != 0) { 382 bp->b_data = unmapped_buf; 383 } else { 384 bp->b_data = (char *)((vm_offset_t)bp->b_data | 385 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 386 } 387 bp->b_iocmd = BIO_READ; 388 bp->b_iodone = cluster_callback; 389 bp->b_blkno = blkno; 390 bp->b_lblkno = lbn; 391 bp->b_offset = tbp->b_offset; 392 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 393 pbgetvp(vp, bp); 394 395 TAILQ_INIT(&bp->b_cluster.cluster_head); 396 397 bp->b_bcount = 0; 398 bp->b_bufsize = 0; 399 bp->b_npages = 0; 400 401 inc = btodb(size); 402 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 403 if (i == 0) { 404 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 405 vfs_drain_busy_pages(tbp); 406 vm_object_pip_add(tbp->b_bufobj->bo_object, 407 tbp->b_npages); 408 for (k = 0; k < tbp->b_npages; k++) 409 vm_page_sbusy(tbp->b_pages[k]); 410 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 411 } else { 412 if ((bp->b_npages * PAGE_SIZE) + 413 round_page(size) > vp->v_mount->mnt_iosize_max) { 414 break; 415 } 416 417 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT | 418 (gbflags & GB_UNMAPPED)); 419 420 /* Don't wait around for locked bufs. */ 421 if (tbp == NULL) 422 break; 423 424 /* 425 * Stop scanning if the buffer is fully valid 426 * (marked B_CACHE), or locked (may be doing a 427 * background write), or if the buffer is not 428 * VMIO backed. The clustering code can only deal 429 * with VMIO-backed buffers. The bo lock is not 430 * required for the BKGRDINPROG check since it 431 * can not be set without the buf lock. 432 */ 433 if ((tbp->b_vflags & BV_BKGRDINPROG) || 434 (tbp->b_flags & B_CACHE) || 435 (tbp->b_flags & B_VMIO) == 0) { 436 bqrelse(tbp); 437 break; 438 } 439 440 /* 441 * The buffer must be completely invalid in order to 442 * take part in the cluster. If it is partially valid 443 * then we stop. 444 */ 445 off = tbp->b_offset; 446 tsize = size; 447 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 448 for (j = 0; tsize > 0; j++) { 449 toff = off & PAGE_MASK; 450 tinc = tsize; 451 if (toff + tinc > PAGE_SIZE) 452 tinc = PAGE_SIZE - toff; 453 VM_OBJECT_ASSERT_WLOCKED(tbp->b_pages[j]->object); 454 if ((tbp->b_pages[j]->valid & 455 vm_page_bits(toff, tinc)) != 0) 456 break; 457 if (vm_page_xbusied(tbp->b_pages[j])) 458 break; 459 vm_object_pip_add(tbp->b_bufobj->bo_object, 1); 460 vm_page_sbusy(tbp->b_pages[j]); 461 off += tinc; 462 tsize -= tinc; 463 } 464 if (tsize > 0) { 465clean_sbusy: 466 vm_object_pip_add(tbp->b_bufobj->bo_object, -j); 467 for (k = 0; k < j; k++) 468 vm_page_sunbusy(tbp->b_pages[k]); 469 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 470 bqrelse(tbp); 471 break; 472 } 473 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 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 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 494 goto clean_sbusy; 495 } 496 } 497 /* 498 * XXX fbp from caller may not be B_ASYNC, but we are going 499 * to biodone() it in cluster_callback() anyway 500 */ 501 BUF_KERNPROC(tbp); 502 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 503 tbp, b_cluster.cluster_entry); 504 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 505 for (j = 0; j < tbp->b_npages; j += 1) { 506 vm_page_t m; 507 m = tbp->b_pages[j]; 508 if ((bp->b_npages == 0) || 509 (bp->b_pages[bp->b_npages-1] != m)) { 510 bp->b_pages[bp->b_npages] = m; 511 bp->b_npages++; 512 } 513 if (m->valid == VM_PAGE_BITS_ALL) 514 tbp->b_pages[j] = bogus_page; 515 } 516 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 517 /* 518 * Don't inherit tbp->b_bufsize as it may be larger due to 519 * a non-page-aligned size. Instead just aggregate using 520 * 'size'. 521 */ 522 if (tbp->b_bcount != size) 523 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 524 if (tbp->b_bufsize != size) 525 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 526 bp->b_bcount += size; 527 bp->b_bufsize += size; 528 } 529 530 /* 531 * Fully valid pages in the cluster are already good and do not need 532 * to be re-read from disk. Replace the page with bogus_page 533 */ 534 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 535 for (j = 0; j < bp->b_npages; j++) { 536 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[j]->object); 537 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL) 538 bp->b_pages[j] = bogus_page; 539 } 540 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 541 if (bp->b_bufsize > bp->b_kvasize) 542 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 543 bp->b_bufsize, bp->b_kvasize); 544 545 if (buf_mapped(bp)) { 546 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 547 (vm_page_t *)bp->b_pages, bp->b_npages); 548 } 549 return (bp); 550} 551 552/* 553 * Cleanup after a clustered read or write. 554 * This is complicated by the fact that any of the buffers might have 555 * extra memory (if there were no empty buffer headers at allocbuf time) 556 * that we will need to shift around. 557 */ 558static void 559cluster_callback(bp) 560 struct buf *bp; 561{ 562 struct buf *nbp, *tbp; 563 int error = 0; 564 565 /* 566 * Must propagate errors to all the components. 567 */ 568 if (bp->b_ioflags & BIO_ERROR) 569 error = bp->b_error; 570 571 if (buf_mapped(bp)) { 572 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), 573 bp->b_npages); 574 } 575 /* 576 * Move memory from the large cluster buffer into the component 577 * buffers and mark IO as done on these. 578 */ 579 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 580 tbp; tbp = nbp) { 581 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 582 if (error) { 583 tbp->b_ioflags |= BIO_ERROR; 584 tbp->b_error = error; 585 } else { 586 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 587 tbp->b_flags &= ~B_INVAL; 588 tbp->b_ioflags &= ~BIO_ERROR; 589 /* 590 * XXX the bdwrite()/bqrelse() issued during 591 * cluster building clears B_RELBUF (see bqrelse() 592 * comment). If direct I/O was specified, we have 593 * to restore it here to allow the buffer and VM 594 * to be freed. 595 */ 596 if (tbp->b_flags & B_DIRECT) 597 tbp->b_flags |= B_RELBUF; 598 } 599 bufdone(tbp); 600 } 601 pbrelvp(bp); 602 relpbuf(bp, &cluster_pbuf_freecnt); 603} 604 605/* 606 * cluster_wbuild_wb: 607 * 608 * Implement modified write build for cluster. 609 * 610 * write_behind = 0 write behind disabled 611 * write_behind = 1 write behind normal (default) 612 * write_behind = 2 write behind backed-off 613 */ 614 615static __inline int 616cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len, 617 int gbflags) 618{ 619 int r = 0; 620 621 switch (write_behind) { 622 case 2: 623 if (start_lbn < len) 624 break; 625 start_lbn -= len; 626 /* FALLTHROUGH */ 627 case 1: 628 r = cluster_wbuild(vp, size, start_lbn, len, gbflags); 629 /* FALLTHROUGH */ 630 default: 631 /* FALLTHROUGH */ 632 break; 633 } 634 return(r); 635} 636 637/* 638 * Do clustered write for FFS. 639 * 640 * Three cases: 641 * 1. Write is not sequential (write asynchronously) 642 * Write is sequential: 643 * 2. beginning of cluster - begin cluster 644 * 3. middle of a cluster - add to cluster 645 * 4. end of a cluster - asynchronously write cluster 646 */ 647void 648cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount, 649 int gbflags) 650{ 651 daddr_t lbn; 652 int maxclen, cursize; 653 int lblocksize; 654 int async; 655 656 if (!unmapped_buf_allowed) 657 gbflags &= ~GB_UNMAPPED; 658 659 if (vp->v_type == VREG) { 660 async = DOINGASYNC(vp); 661 lblocksize = vp->v_mount->mnt_stat.f_iosize; 662 } else { 663 async = 0; 664 lblocksize = bp->b_bufsize; 665 } 666 lbn = bp->b_lblkno; 667 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 668 669 /* Initialize vnode to beginning of file. */ 670 if (lbn == 0) 671 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 672 673 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 674 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 675 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 676 if (vp->v_clen != 0) { 677 /* 678 * Next block is not sequential. 679 * 680 * If we are not writing at end of file, the process 681 * seeked to another point in the file since its last 682 * write, or we have reached our maximum cluster size, 683 * then push the previous cluster. Otherwise try 684 * reallocating to make it sequential. 685 * 686 * Change to algorithm: only push previous cluster if 687 * it was sequential from the point of view of the 688 * seqcount heuristic, otherwise leave the buffer 689 * intact so we can potentially optimize the I/O 690 * later on in the buf_daemon or update daemon 691 * flush. 692 */ 693 cursize = vp->v_lastw - vp->v_cstart + 1; 694 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 695 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 696 if (!async && seqcount > 0) { 697 cluster_wbuild_wb(vp, lblocksize, 698 vp->v_cstart, cursize, gbflags); 699 } 700 } else { 701 struct buf **bpp, **endbp; 702 struct cluster_save *buflist; 703 704 buflist = cluster_collectbufs(vp, bp, gbflags); 705 if (buflist == NULL) { 706 /* 707 * Cluster build failed so just write 708 * it now. 709 */ 710 bawrite(bp); 711 return; 712 } 713 endbp = &buflist->bs_children 714 [buflist->bs_nchildren - 1]; 715 if (VOP_REALLOCBLKS(vp, buflist)) { 716 /* 717 * Failed, push the previous cluster 718 * if *really* writing sequentially 719 * in the logical file (seqcount > 1), 720 * otherwise delay it in the hopes that 721 * the low level disk driver can 722 * optimize the write ordering. 723 */ 724 for (bpp = buflist->bs_children; 725 bpp < endbp; bpp++) 726 brelse(*bpp); 727 free(buflist, M_SEGMENT); 728 if (seqcount > 1) { 729 cluster_wbuild_wb(vp, 730 lblocksize, vp->v_cstart, 731 cursize, gbflags); 732 } 733 } else { 734 /* 735 * Succeeded, keep building cluster. 736 */ 737 for (bpp = buflist->bs_children; 738 bpp <= endbp; bpp++) 739 bdwrite(*bpp); 740 free(buflist, M_SEGMENT); 741 vp->v_lastw = lbn; 742 vp->v_lasta = bp->b_blkno; 743 return; 744 } 745 } 746 } 747 /* 748 * Consider beginning a cluster. If at end of file, make 749 * cluster as large as possible, otherwise find size of 750 * existing cluster. 751 */ 752 if ((vp->v_type == VREG) && 753 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 754 (bp->b_blkno == bp->b_lblkno) && 755 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 756 bp->b_blkno == -1)) { 757 bawrite(bp); 758 vp->v_clen = 0; 759 vp->v_lasta = bp->b_blkno; 760 vp->v_cstart = lbn + 1; 761 vp->v_lastw = lbn; 762 return; 763 } 764 vp->v_clen = maxclen; 765 if (!async && maxclen == 0) { /* I/O not contiguous */ 766 vp->v_cstart = lbn + 1; 767 bawrite(bp); 768 } else { /* Wait for rest of cluster */ 769 vp->v_cstart = lbn; 770 bdwrite(bp); 771 } 772 } else if (lbn == vp->v_cstart + vp->v_clen) { 773 /* 774 * At end of cluster, write it out if seqcount tells us we 775 * are operating sequentially, otherwise let the buf or 776 * update daemon handle it. 777 */ 778 bdwrite(bp); 779 if (seqcount > 1) { 780 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, 781 vp->v_clen + 1, gbflags); 782 } 783 vp->v_clen = 0; 784 vp->v_cstart = lbn + 1; 785 } else if (vm_page_count_severe()) { 786 /* 787 * We are low on memory, get it going NOW 788 */ 789 bawrite(bp); 790 } else { 791 /* 792 * In the middle of a cluster, so just delay the I/O for now. 793 */ 794 bdwrite(bp); 795 } 796 vp->v_lastw = lbn; 797 vp->v_lasta = bp->b_blkno; 798} 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 */ 807int 808cluster_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 if (tbp->b_pin_count > 0) { 848 BUF_UNLOCK(tbp); 849 ++start_lbn; 850 --len; 851 continue; 852 } 853 bremfree(tbp); 854 tbp->b_flags &= ~B_DONE; 855 856 /* 857 * Extra memory in the buffer, punt on this buffer. 858 * XXX we could handle this in most cases, but we would 859 * have to push the extra memory down to after our max 860 * possible cluster size and then potentially pull it back 861 * up if the cluster was terminated prematurely--too much 862 * hassle. 863 */ 864 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 865 (B_CLUSTEROK | B_VMIO)) || 866 (tbp->b_bcount != tbp->b_bufsize) || 867 (tbp->b_bcount != size) || 868 (len == 1) || 869 ((bp = (vp->v_vflag & VV_MD) != 0 ? 870 trypbuf(&cluster_pbuf_freecnt) : 871 getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 872 totalwritten += tbp->b_bufsize; 873 bawrite(tbp); 874 ++start_lbn; 875 --len; 876 continue; 877 } 878 879 /* 880 * We got a pbuf to make the cluster in. 881 * so initialise it. 882 */ 883 TAILQ_INIT(&bp->b_cluster.cluster_head); 884 bp->b_bcount = 0; 885 bp->b_bufsize = 0; 886 bp->b_npages = 0; 887 if (tbp->b_wcred != NOCRED) 888 bp->b_wcred = crhold(tbp->b_wcred); 889 890 bp->b_blkno = tbp->b_blkno; 891 bp->b_lblkno = tbp->b_lblkno; 892 bp->b_offset = tbp->b_offset; 893 894 /* 895 * We are synthesizing a buffer out of vm_page_t's, but 896 * if the block size is not page aligned then the starting 897 * address may not be either. Inherit the b_data offset 898 * from the original buffer. 899 */ 900 if ((gbflags & GB_UNMAPPED) == 0 || 901 (tbp->b_flags & B_VMIO) == 0) { 902 bp->b_data = (char *)((vm_offset_t)bp->b_data | 903 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 904 } else { 905 bp->b_data = unmapped_buf; 906 } 907 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO | 908 B_NEEDCOMMIT)); 909 bp->b_iodone = cluster_callback; 910 pbgetvp(vp, bp); 911 /* 912 * From this location in the file, scan forward to see 913 * if there are buffers with adjacent data that need to 914 * be written as well. 915 */ 916 for (i = 0; i < len; ++i, ++start_lbn) { 917 if (i != 0) { /* If not the first buffer */ 918 /* 919 * If the adjacent data is not even in core it 920 * can't need to be written. 921 */ 922 BO_LOCK(bo); 923 if ((tbp = gbincore(bo, start_lbn)) == NULL || 924 (tbp->b_vflags & BV_BKGRDINPROG)) { 925 BO_UNLOCK(bo); 926 break; 927 } 928 929 /* 930 * If it IS in core, but has different 931 * characteristics, or is locked (which 932 * means it could be undergoing a background 933 * I/O or be in a weird state), then don't 934 * cluster with it. 935 */ 936 if (BUF_LOCK(tbp, 937 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 938 BO_LOCKPTR(bo))) 939 break; 940 941 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 942 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 943 != (B_DELWRI | B_CLUSTEROK | 944 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 945 tbp->b_wcred != bp->b_wcred) { 946 BUF_UNLOCK(tbp); 947 break; 948 } 949 950 /* 951 * Check that the combined cluster 952 * would make sense with regard to pages 953 * and would not be too large 954 */ 955 if ((tbp->b_bcount != size) || 956 ((bp->b_blkno + (dbsize * i)) != 957 tbp->b_blkno) || 958 ((tbp->b_npages + bp->b_npages) > 959 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 960 BUF_UNLOCK(tbp); 961 break; 962 } 963 964 /* 965 * Do not pull in pinned buffers. 966 */ 967 if (tbp->b_pin_count > 0) { 968 BUF_UNLOCK(tbp); 969 break; 970 } 971 972 /* 973 * Ok, it's passed all the tests, 974 * so remove it from the free list 975 * and mark it busy. We will use it. 976 */ 977 bremfree(tbp); 978 tbp->b_flags &= ~B_DONE; 979 } /* end of code for non-first buffers only */ 980 /* 981 * If the IO is via the VM then we do some 982 * special VM hackery (yuck). Since the buffer's 983 * block size may not be page-aligned it is possible 984 * for a page to be shared between two buffers. We 985 * have to get rid of the duplication when building 986 * the cluster. 987 */ 988 if (tbp->b_flags & B_VMIO) { 989 vm_page_t m; 990 991 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 992 if (i == 0) { 993 vfs_drain_busy_pages(tbp); 994 } else { /* if not first buffer */ 995 for (j = 0; j < tbp->b_npages; j += 1) { 996 m = tbp->b_pages[j]; 997 if (vm_page_xbusied(m)) { 998 VM_OBJECT_WUNLOCK( 999 tbp->b_object); 1000 bqrelse(tbp); 1001 goto finishcluster; 1002 } 1003 } 1004 } 1005 for (j = 0; j < tbp->b_npages; j += 1) { 1006 m = tbp->b_pages[j]; 1007 vm_page_sbusy(m); 1008 vm_object_pip_add(m->object, 1); 1009 if ((bp->b_npages == 0) || 1010 (bp->b_pages[bp->b_npages - 1] != m)) { 1011 bp->b_pages[bp->b_npages] = m; 1012 bp->b_npages++; 1013 } 1014 } 1015 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 1016 } 1017 bp->b_bcount += size; 1018 bp->b_bufsize += size; 1019 /* 1020 * If any of the clustered buffers have their 1021 * B_BARRIER flag set, transfer that request to 1022 * the cluster. 1023 */ 1024 bp->b_flags |= (tbp->b_flags & B_BARRIER); 1025 tbp->b_flags &= ~(B_DONE | B_BARRIER); 1026 tbp->b_flags |= B_ASYNC; 1027 tbp->b_ioflags &= ~BIO_ERROR; 1028 tbp->b_iocmd = BIO_WRITE; 1029 bundirty(tbp); 1030 reassignbuf(tbp); /* put on clean list */ 1031 bufobj_wref(tbp->b_bufobj); 1032 BUF_KERNPROC(tbp); 1033 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 1034 tbp, b_cluster.cluster_entry); 1035 } 1036 finishcluster: 1037 if (buf_mapped(bp)) { 1038 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 1039 (vm_page_t *)bp->b_pages, bp->b_npages); 1040 } 1041 if (bp->b_bufsize > bp->b_kvasize) 1042 panic( 1043 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 1044 bp->b_bufsize, bp->b_kvasize); 1045 totalwritten += bp->b_bufsize; 1046 bp->b_dirtyoff = 0; 1047 bp->b_dirtyend = bp->b_bufsize; 1048 bawrite(bp); 1049 1050 len -= i; 1051 } 1052 return totalwritten; 1053} 1054 1055/* 1056 * Collect together all the buffers in a cluster. 1057 * Plus add one additional buffer. 1058 */ 1059static struct cluster_save * 1060cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int gbflags) 1061{ 1062 struct cluster_save *buflist; 1063 struct buf *bp; 1064 daddr_t lbn; 1065 int i, j, len, error; 1066 1067 len = vp->v_lastw - vp->v_cstart + 1; 1068 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 1069 M_SEGMENT, M_WAITOK); 1070 buflist->bs_nchildren = 0; 1071 buflist->bs_children = (struct buf **) (buflist + 1); 1072 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 1073 error = bread_gb(vp, lbn, last_bp->b_bcount, NOCRED, 1074 gbflags, &bp); 1075 if (error != 0) { 1076 /* 1077 * If read fails, release collected buffers 1078 * and return failure. 1079 */ 1080 for (j = 0; j < i; j++) 1081 brelse(buflist->bs_children[j]); 1082 free(buflist, M_SEGMENT); 1083 return (NULL); 1084 } 1085 buflist->bs_children[i] = bp; 1086 if (bp->b_blkno == bp->b_lblkno) 1087 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 1088 NULL, NULL); 1089 } 1090 buflist->bs_children[i] = bp = last_bp; 1091 if (bp->b_blkno == bp->b_lblkno) 1092 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1093 buflist->bs_nchildren = i + 1; 1094 return (buflist); 1095} 1096