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 /* Page expended to mark partially backed buffers */ 80 extern vm_page_t bogus_page; 81 82 /* 83 * Read data to a buf, including read-ahead if we find this to be beneficial. 84 * cluster_read replaces bread. 85 */ 86 int 87 cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, long size, 88 struct ucred *cred, long totread, int seqcount, int gbflags, 89 struct buf **bpp) 90 { 91 struct buf *bp, *rbp, *reqbp; 92 struct bufobj *bo; 93 daddr_t blkno, origblkno; 94 int maxra, racluster; 95 int error, ncontig; 96 int i; 97 98 error = 0; 99 bo = &vp->v_bufobj; 100 if (!unmapped_buf_allowed) 101 gbflags &= ~GB_UNMAPPED; 102 103 /* 104 * Try to limit the amount of read-ahead by a few 105 * ad-hoc parameters. This needs work!!! 106 */ 107 racluster = vp->v_mount->mnt_iosize_max / size; 108 maxra = seqcount; 109 maxra = min(read_max, maxra); 110 maxra = min(nbuf/8, maxra); 111 if (((u_quad_t)(lblkno + maxra + 1) * size) > filesize) 112 maxra = (filesize / size) - lblkno; 113 114 /* 115 * get the requested block 116 */ 117 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0, gbflags); 118 origblkno = lblkno; 119 120 /* 121 * if it is in the cache, then check to see if the reads have been 122 * sequential. If they have, then try some read-ahead, otherwise 123 * back-off on prospective read-aheads. 124 */ 125 if (bp->b_flags & B_CACHE) { 126 if (!seqcount) { 127 return 0; 128 } else if ((bp->b_flags & B_RAM) == 0) { 129 return 0; 130 } else { 131 bp->b_flags &= ~B_RAM; 132 BO_LOCK(bo); 133 for (i = 1; i < maxra; i++) { 134 /* 135 * Stop if the buffer does not exist or it 136 * is invalid (about to go away?) 137 */ 138 rbp = gbincore(&vp->v_bufobj, lblkno+i); 139 if (rbp == NULL || (rbp->b_flags & B_INVAL)) 140 break; 141 142 /* 143 * Set another read-ahead mark so we know 144 * to check again. (If we can lock the 145 * buffer without waiting) 146 */ 147 if ((((i % racluster) == (racluster - 1)) || 148 (i == (maxra - 1))) 149 && (0 == BUF_LOCK(rbp, 150 LK_EXCLUSIVE | LK_NOWAIT, NULL))) { 151 rbp->b_flags |= B_RAM; 152 BUF_UNLOCK(rbp); 153 } 154 } 155 BO_UNLOCK(bo); 156 if (i >= maxra) { 157 return 0; 158 } 159 lblkno += i; 160 } 161 reqbp = bp = NULL; 162 /* 163 * If it isn't in the cache, then get a chunk from 164 * disk if sequential, otherwise just get the block. 165 */ 166 } else { 167 off_t firstread = bp->b_offset; 168 int nblks; 169 170 KASSERT(bp->b_offset != NOOFFSET, 171 ("cluster_read: no buffer offset")); 172 173 ncontig = 0; 174 175 /* 176 * Compute the total number of blocks that we should read 177 * synchronously. 178 */ 179 if (firstread + totread > filesize) 180 totread = filesize - firstread; 181 nblks = howmany(totread, size); 182 if (nblks > racluster) 183 nblks = racluster; 184 185 /* 186 * Now compute the number of contiguous blocks. 187 */ 188 if (nblks > 1) { 189 error = VOP_BMAP(vp, lblkno, NULL, 190 &blkno, &ncontig, NULL); 191 /* 192 * If this failed to map just do the original block. 193 */ 194 if (error || blkno == -1) 195 ncontig = 0; 196 } 197 198 /* 199 * If we have contiguous data available do a cluster 200 * otherwise just read the requested block. 201 */ 202 if (ncontig) { 203 /* Account for our first block. */ 204 ncontig = min(ncontig + 1, nblks); 205 if (ncontig < nblks) 206 nblks = ncontig; 207 bp = cluster_rbuild(vp, filesize, lblkno, 208 blkno, size, nblks, gbflags, bp); 209 lblkno += (bp->b_bufsize / size); 210 } else { 211 bp->b_flags |= B_RAM; 212 bp->b_iocmd = BIO_READ; 213 lblkno += 1; 214 } 215 } 216 217 /* 218 * handle the synchronous read so that it is available ASAP. 219 */ 220 if (bp) { 221 if ((bp->b_flags & B_CLUSTER) == 0) { 222 vfs_busy_pages(bp, 0); 223 } 224 bp->b_flags &= ~B_INVAL; 225 bp->b_ioflags &= ~BIO_ERROR; 226 if ((bp->b_flags & B_ASYNC) || bp->b_iodone != NULL) 227 BUF_KERNPROC(bp); 228 bp->b_iooffset = dbtob(bp->b_blkno); 229 bstrategy(bp); 230 curthread->td_ru.ru_inblock++; 231 } 232 233 /* 234 * If we have been doing sequential I/O, then do some read-ahead. 235 */ 236 while (lblkno < (origblkno + maxra)) { 237 error = VOP_BMAP(vp, lblkno, NULL, &blkno, &ncontig, NULL); 238 if (error) 239 break; 240 241 if (blkno == -1) 242 break; 243 244 /* 245 * We could throttle ncontig here by maxra but we might as 246 * well read the data if it is contiguous. We're throttled 247 * by racluster anyway. 248 */ 249 if (ncontig) { 250 ncontig = min(ncontig + 1, racluster); 251 rbp = cluster_rbuild(vp, filesize, lblkno, blkno, 252 size, ncontig, gbflags, NULL); 253 lblkno += (rbp->b_bufsize / size); 254 if (rbp->b_flags & B_DELWRI) { 255 bqrelse(rbp); 256 continue; 257 } 258 } else { 259 rbp = getblk(vp, lblkno, size, 0, 0, gbflags); 260 lblkno += 1; 261 if (rbp->b_flags & B_DELWRI) { 262 bqrelse(rbp); 263 continue; 264 } 265 rbp->b_flags |= B_ASYNC | B_RAM; 266 rbp->b_iocmd = BIO_READ; 267 rbp->b_blkno = blkno; 268 } 269 if (rbp->b_flags & B_CACHE) { 270 rbp->b_flags &= ~B_ASYNC; 271 bqrelse(rbp); 272 continue; 273 } 274 if ((rbp->b_flags & B_CLUSTER) == 0) { 275 vfs_busy_pages(rbp, 0); 276 } 277 rbp->b_flags &= ~B_INVAL; 278 rbp->b_ioflags &= ~BIO_ERROR; 279 if ((rbp->b_flags & B_ASYNC) || rbp->b_iodone != NULL) 280 BUF_KERNPROC(rbp); 281 rbp->b_iooffset = dbtob(rbp->b_blkno); 282 bstrategy(rbp); 283 curthread->td_ru.ru_inblock++; 284 } 285 286 if (reqbp) 287 return (bufwait(reqbp)); 288 else 289 return (error); 290 } 291 292 /* 293 * If blocks are contiguous on disk, use this to provide clustered 294 * read ahead. We will read as many blocks as possible sequentially 295 * and then parcel them up into logical blocks in the buffer hash table. 296 */ 297 static struct buf * 298 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 299 daddr_t blkno, long size, int run, int gbflags, struct buf *fbp) 300 { 301 struct bufobj *bo; 302 struct buf *bp, *tbp; 303 daddr_t bn; 304 off_t off; 305 long tinc, tsize; 306 int i, inc, j, toff; 307 308 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 309 ("cluster_rbuild: size %ld != f_iosize %jd\n", 310 size, (intmax_t)vp->v_mount->mnt_stat.f_iosize)); 311 312 /* 313 * avoid a division 314 */ 315 while ((u_quad_t) size * (lbn + run) > filesize) { 316 --run; 317 } 318 319 if (fbp) { 320 tbp = fbp; 321 tbp->b_iocmd = BIO_READ; 322 } else { 323 tbp = getblk(vp, lbn, size, 0, 0, gbflags); 324 if (tbp->b_flags & B_CACHE) 325 return tbp; 326 tbp->b_flags |= B_ASYNC | B_RAM; 327 tbp->b_iocmd = BIO_READ; 328 } 329 tbp->b_blkno = blkno; 330 if( (tbp->b_flags & B_MALLOC) || 331 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 332 return tbp; 333 334 bp = trypbuf(&cluster_pbuf_freecnt); 335 if (bp == 0) 336 return tbp; 337 338 /* 339 * We are synthesizing a buffer out of vm_page_t's, but 340 * if the block size is not page aligned then the starting 341 * address may not be either. Inherit the b_data offset 342 * from the original buffer. 343 */ 344 bp->b_flags = B_ASYNC | B_CLUSTER | B_VMIO; 345 if ((gbflags & GB_UNMAPPED) != 0) { 346 bp->b_flags |= B_UNMAPPED; 347 bp->b_data = unmapped_buf; 348 } else { 349 bp->b_data = (char *)((vm_offset_t)bp->b_data | 350 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 351 } 352 bp->b_iocmd = BIO_READ; 353 bp->b_iodone = cluster_callback; 354 bp->b_blkno = blkno; 355 bp->b_lblkno = lbn; 356 bp->b_offset = tbp->b_offset; 357 KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); 358 pbgetvp(vp, bp); 359 360 TAILQ_INIT(&bp->b_cluster.cluster_head); 361 362 bp->b_bcount = 0; 363 bp->b_bufsize = 0; 364 bp->b_npages = 0; 365 366 inc = btodb(size); 367 bo = &vp->v_bufobj; 368 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 369 if (i != 0) { 370 if ((bp->b_npages * PAGE_SIZE) + 371 round_page(size) > vp->v_mount->mnt_iosize_max) { 372 break; 373 } 374 375 tbp = getblk(vp, lbn + i, size, 0, 0, GB_LOCK_NOWAIT | 376 (gbflags & GB_UNMAPPED)); 377 378 /* Don't wait around for locked bufs. */ 379 if (tbp == NULL) 380 break; 381 382 /* 383 * Stop scanning if the buffer is fully valid 384 * (marked B_CACHE), or locked (may be doing a 385 * background write), or if the buffer is not 386 * VMIO backed. The clustering code can only deal 387 * with VMIO-backed buffers. 388 */ 389 BO_LOCK(bo); 390 if ((tbp->b_vflags & BV_BKGRDINPROG) || 391 (tbp->b_flags & B_CACHE) || 392 (tbp->b_flags & B_VMIO) == 0) { 393 BO_UNLOCK(bo); 394 bqrelse(tbp); 395 break; 396 } 397 BO_UNLOCK(bo); 398 399 /* 400 * The buffer must be completely invalid in order to 401 * take part in the cluster. If it is partially valid 402 * then we stop. 403 */ 404 off = tbp->b_offset; 405 tsize = size; 406 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 407 for (j = 0; tsize > 0; j++) { 408 toff = off & PAGE_MASK; 409 tinc = tsize; 410 if (toff + tinc > PAGE_SIZE) 411 tinc = PAGE_SIZE - toff; 412 VM_OBJECT_ASSERT_WLOCKED(tbp->b_pages[j]->object); 413 if ((tbp->b_pages[j]->valid & 414 vm_page_bits(toff, tinc)) != 0) 415 break; 416 off += tinc; 417 tsize -= tinc; 418 } 419 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 420 if (tsize > 0) { 421 bqrelse(tbp); 422 break; 423 } 424 425 /* 426 * Set a read-ahead mark as appropriate 427 */ 428 if ((fbp && (i == 1)) || (i == (run - 1))) 429 tbp->b_flags |= B_RAM; 430 431 /* 432 * Set the buffer up for an async read (XXX should 433 * we do this only if we do not wind up brelse()ing?). 434 * Set the block number if it isn't set, otherwise 435 * if it is make sure it matches the block number we 436 * expect. 437 */ 438 tbp->b_flags |= B_ASYNC; 439 tbp->b_iocmd = BIO_READ; 440 if (tbp->b_blkno == tbp->b_lblkno) { 441 tbp->b_blkno = bn; 442 } else if (tbp->b_blkno != bn) { 443 brelse(tbp); 444 break; 445 } 446 } 447 /* 448 * XXX fbp from caller may not be B_ASYNC, but we are going 449 * to biodone() it in cluster_callback() anyway 450 */ 451 BUF_KERNPROC(tbp); 452 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 453 tbp, b_cluster.cluster_entry); 454 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 455 for (j = 0; j < tbp->b_npages; j += 1) { 456 vm_page_t m; 457 m = tbp->b_pages[j]; 458 vm_page_io_start(m); 459 vm_object_pip_add(m->object, 1); 460 if ((bp->b_npages == 0) || 461 (bp->b_pages[bp->b_npages-1] != m)) { 462 bp->b_pages[bp->b_npages] = m; 463 bp->b_npages++; 464 } 465 if (m->valid == VM_PAGE_BITS_ALL) 466 tbp->b_pages[j] = bogus_page; 467 } 468 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 469 /* 470 * Don't inherit tbp->b_bufsize as it may be larger due to 471 * a non-page-aligned size. Instead just aggregate using 472 * 'size'. 473 */ 474 if (tbp->b_bcount != size) 475 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 476 if (tbp->b_bufsize != size) 477 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 478 bp->b_bcount += size; 479 bp->b_bufsize += size; 480 } 481 482 /* 483 * Fully valid pages in the cluster are already good and do not need 484 * to be re-read from disk. Replace the page with bogus_page 485 */ 486 VM_OBJECT_WLOCK(bp->b_bufobj->bo_object); 487 for (j = 0; j < bp->b_npages; j++) { 488 VM_OBJECT_ASSERT_WLOCKED(bp->b_pages[j]->object); 489 if (bp->b_pages[j]->valid == VM_PAGE_BITS_ALL) 490 bp->b_pages[j] = bogus_page; 491 } 492 VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object); 493 if (bp->b_bufsize > bp->b_kvasize) 494 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 495 bp->b_bufsize, bp->b_kvasize); 496 bp->b_kvasize = bp->b_bufsize; 497 498 if ((bp->b_flags & B_UNMAPPED) == 0) { 499 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 500 (vm_page_t *)bp->b_pages, bp->b_npages); 501 } 502 return (bp); 503 } 504 505 /* 506 * Cleanup after a clustered read or write. 507 * This is complicated by the fact that any of the buffers might have 508 * extra memory (if there were no empty buffer headers at allocbuf time) 509 * that we will need to shift around. 510 */ 511 static void 512 cluster_callback(bp) 513 struct buf *bp; 514 { 515 struct buf *nbp, *tbp; 516 int error = 0; 517 518 /* 519 * Must propogate errors to all the components. 520 */ 521 if (bp->b_ioflags & BIO_ERROR) 522 error = bp->b_error; 523 524 if ((bp->b_flags & B_UNMAPPED) == 0) { 525 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), 526 bp->b_npages); 527 } 528 /* 529 * Move memory from the large cluster buffer into the component 530 * buffers and mark IO as done on these. 531 */ 532 for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); 533 tbp; tbp = nbp) { 534 nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); 535 if (error) { 536 tbp->b_ioflags |= BIO_ERROR; 537 tbp->b_error = error; 538 } else { 539 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 540 tbp->b_flags &= ~B_INVAL; 541 tbp->b_ioflags &= ~BIO_ERROR; 542 /* 543 * XXX the bdwrite()/bqrelse() issued during 544 * cluster building clears B_RELBUF (see bqrelse() 545 * comment). If direct I/O was specified, we have 546 * to restore it here to allow the buffer and VM 547 * to be freed. 548 */ 549 if (tbp->b_flags & B_DIRECT) 550 tbp->b_flags |= B_RELBUF; 551 } 552 bufdone(tbp); 553 } 554 pbrelvp(bp); 555 relpbuf(bp, &cluster_pbuf_freecnt); 556 } 557 558 /* 559 * cluster_wbuild_wb: 560 * 561 * Implement modified write build for cluster. 562 * 563 * write_behind = 0 write behind disabled 564 * write_behind = 1 write behind normal (default) 565 * write_behind = 2 write behind backed-off 566 */ 567 568 static __inline int 569 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len, 570 int gbflags) 571 { 572 int r = 0; 573 574 switch (write_behind) { 575 case 2: 576 if (start_lbn < len) 577 break; 578 start_lbn -= len; 579 /* FALLTHROUGH */ 580 case 1: 581 r = cluster_wbuild(vp, size, start_lbn, len, gbflags); 582 /* FALLTHROUGH */ 583 default: 584 /* FALLTHROUGH */ 585 break; 586 } 587 return(r); 588 } 589 590 /* 591 * Do clustered write for FFS. 592 * 593 * Three cases: 594 * 1. Write is not sequential (write asynchronously) 595 * Write is sequential: 596 * 2. beginning of cluster - begin cluster 597 * 3. middle of a cluster - add to cluster 598 * 4. end of a cluster - asynchronously write cluster 599 */ 600 void 601 cluster_write(struct vnode *vp, struct buf *bp, u_quad_t filesize, int seqcount, 602 int gbflags) 603 { 604 daddr_t lbn; 605 int maxclen, cursize; 606 int lblocksize; 607 int async; 608 609 if (!unmapped_buf_allowed) 610 gbflags &= ~GB_UNMAPPED; 611 612 if (vp->v_type == VREG) { 613 async = DOINGASYNC(vp); 614 lblocksize = vp->v_mount->mnt_stat.f_iosize; 615 } else { 616 async = 0; 617 lblocksize = bp->b_bufsize; 618 } 619 lbn = bp->b_lblkno; 620 KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); 621 622 /* Initialize vnode to beginning of file. */ 623 if (lbn == 0) 624 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 625 626 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 627 (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { 628 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 629 if (vp->v_clen != 0) { 630 /* 631 * Next block is not sequential. 632 * 633 * If we are not writing at end of file, the process 634 * seeked to another point in the file since its last 635 * write, or we have reached our maximum cluster size, 636 * then push the previous cluster. Otherwise try 637 * reallocating to make it sequential. 638 * 639 * Change to algorithm: only push previous cluster if 640 * it was sequential from the point of view of the 641 * seqcount heuristic, otherwise leave the buffer 642 * intact so we can potentially optimize the I/O 643 * later on in the buf_daemon or update daemon 644 * flush. 645 */ 646 cursize = vp->v_lastw - vp->v_cstart + 1; 647 if (((u_quad_t) bp->b_offset + lblocksize) != filesize || 648 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 649 if (!async && seqcount > 0) { 650 cluster_wbuild_wb(vp, lblocksize, 651 vp->v_cstart, cursize, gbflags); 652 } 653 } else { 654 struct buf **bpp, **endbp; 655 struct cluster_save *buflist; 656 657 buflist = cluster_collectbufs(vp, bp, gbflags); 658 endbp = &buflist->bs_children 659 [buflist->bs_nchildren - 1]; 660 if (VOP_REALLOCBLKS(vp, buflist)) { 661 /* 662 * Failed, push the previous cluster 663 * if *really* writing sequentially 664 * in the logical file (seqcount > 1), 665 * otherwise delay it in the hopes that 666 * the low level disk driver can 667 * optimize the write ordering. 668 */ 669 for (bpp = buflist->bs_children; 670 bpp < endbp; bpp++) 671 brelse(*bpp); 672 free(buflist, M_SEGMENT); 673 if (seqcount > 1) { 674 cluster_wbuild_wb(vp, 675 lblocksize, vp->v_cstart, 676 cursize, gbflags); 677 } 678 } else { 679 /* 680 * Succeeded, keep building cluster. 681 */ 682 for (bpp = buflist->bs_children; 683 bpp <= endbp; bpp++) 684 bdwrite(*bpp); 685 free(buflist, M_SEGMENT); 686 vp->v_lastw = lbn; 687 vp->v_lasta = bp->b_blkno; 688 return; 689 } 690 } 691 } 692 /* 693 * Consider beginning a cluster. If at end of file, make 694 * cluster as large as possible, otherwise find size of 695 * existing cluster. 696 */ 697 if ((vp->v_type == VREG) && 698 ((u_quad_t) bp->b_offset + lblocksize) != filesize && 699 (bp->b_blkno == bp->b_lblkno) && 700 (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || 701 bp->b_blkno == -1)) { 702 bawrite(bp); 703 vp->v_clen = 0; 704 vp->v_lasta = bp->b_blkno; 705 vp->v_cstart = lbn + 1; 706 vp->v_lastw = lbn; 707 return; 708 } 709 vp->v_clen = maxclen; 710 if (!async && maxclen == 0) { /* I/O not contiguous */ 711 vp->v_cstart = lbn + 1; 712 bawrite(bp); 713 } else { /* Wait for rest of cluster */ 714 vp->v_cstart = lbn; 715 bdwrite(bp); 716 } 717 } else if (lbn == vp->v_cstart + vp->v_clen) { 718 /* 719 * At end of cluster, write it out if seqcount tells us we 720 * are operating sequentially, otherwise let the buf or 721 * update daemon handle it. 722 */ 723 bdwrite(bp); 724 if (seqcount > 1) { 725 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, 726 vp->v_clen + 1, gbflags); 727 } 728 vp->v_clen = 0; 729 vp->v_cstart = lbn + 1; 730 } else if (vm_page_count_severe()) { 731 /* 732 * We are low on memory, get it going NOW 733 */ 734 bawrite(bp); 735 } else { 736 /* 737 * In the middle of a cluster, so just delay the I/O for now. 738 */ 739 bdwrite(bp); 740 } 741 vp->v_lastw = lbn; 742 vp->v_lasta = bp->b_blkno; 743 } 744 745 746 /* 747 * This is an awful lot like cluster_rbuild...wish they could be combined. 748 * The last lbn argument is the current block on which I/O is being 749 * performed. Check to see that it doesn't fall in the middle of 750 * the current block (if last_bp == NULL). 751 */ 752 int 753 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len, 754 int gbflags) 755 { 756 struct buf *bp, *tbp; 757 struct bufobj *bo; 758 int i, j; 759 int totalwritten = 0; 760 int dbsize = btodb(size); 761 762 if (!unmapped_buf_allowed) 763 gbflags &= ~GB_UNMAPPED; 764 765 bo = &vp->v_bufobj; 766 while (len > 0) { 767 /* 768 * If the buffer is not delayed-write (i.e. dirty), or it 769 * is delayed-write but either locked or inval, it cannot 770 * partake in the clustered write. 771 */ 772 BO_LOCK(bo); 773 if ((tbp = gbincore(&vp->v_bufobj, start_lbn)) == NULL || 774 (tbp->b_vflags & BV_BKGRDINPROG)) { 775 BO_UNLOCK(bo); 776 ++start_lbn; 777 --len; 778 continue; 779 } 780 if (BUF_LOCK(tbp, 781 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, BO_MTX(bo))) { 782 ++start_lbn; 783 --len; 784 continue; 785 } 786 if ((tbp->b_flags & (B_INVAL | B_DELWRI)) != B_DELWRI) { 787 BUF_UNLOCK(tbp); 788 ++start_lbn; 789 --len; 790 continue; 791 } 792 if (tbp->b_pin_count > 0) { 793 BUF_UNLOCK(tbp); 794 ++start_lbn; 795 --len; 796 continue; 797 } 798 bremfree(tbp); 799 tbp->b_flags &= ~B_DONE; 800 801 /* 802 * Extra memory in the buffer, punt on this buffer. 803 * XXX we could handle this in most cases, but we would 804 * have to push the extra memory down to after our max 805 * possible cluster size and then potentially pull it back 806 * up if the cluster was terminated prematurely--too much 807 * hassle. 808 */ 809 if (((tbp->b_flags & (B_CLUSTEROK | B_MALLOC | B_VMIO)) != 810 (B_CLUSTEROK | B_VMIO)) || 811 (tbp->b_bcount != tbp->b_bufsize) || 812 (tbp->b_bcount != size) || 813 (len == 1) || 814 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 815 totalwritten += tbp->b_bufsize; 816 bawrite(tbp); 817 ++start_lbn; 818 --len; 819 continue; 820 } 821 822 /* 823 * We got a pbuf to make the cluster in. 824 * so initialise it. 825 */ 826 TAILQ_INIT(&bp->b_cluster.cluster_head); 827 bp->b_bcount = 0; 828 bp->b_bufsize = 0; 829 bp->b_npages = 0; 830 if (tbp->b_wcred != NOCRED) 831 bp->b_wcred = crhold(tbp->b_wcred); 832 833 bp->b_blkno = tbp->b_blkno; 834 bp->b_lblkno = tbp->b_lblkno; 835 bp->b_offset = tbp->b_offset; 836 837 /* 838 * We are synthesizing a buffer out of vm_page_t's, but 839 * if the block size is not page aligned then the starting 840 * address may not be either. Inherit the b_data offset 841 * from the original buffer. 842 */ 843 if ((gbflags & GB_UNMAPPED) == 0 || 844 (tbp->b_flags & B_VMIO) == 0) { 845 bp->b_data = (char *)((vm_offset_t)bp->b_data | 846 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 847 } else { 848 bp->b_flags |= B_UNMAPPED; 849 bp->b_data = unmapped_buf; 850 } 851 bp->b_flags |= B_CLUSTER | (tbp->b_flags & (B_VMIO | 852 B_NEEDCOMMIT)); 853 bp->b_iodone = cluster_callback; 854 pbgetvp(vp, bp); 855 /* 856 * From this location in the file, scan forward to see 857 * if there are buffers with adjacent data that need to 858 * be written as well. 859 */ 860 for (i = 0; i < len; ++i, ++start_lbn) { 861 if (i != 0) { /* If not the first buffer */ 862 /* 863 * If the adjacent data is not even in core it 864 * can't need to be written. 865 */ 866 BO_LOCK(bo); 867 if ((tbp = gbincore(bo, start_lbn)) == NULL || 868 (tbp->b_vflags & BV_BKGRDINPROG)) { 869 BO_UNLOCK(bo); 870 break; 871 } 872 873 /* 874 * If it IS in core, but has different 875 * characteristics, or is locked (which 876 * means it could be undergoing a background 877 * I/O or be in a weird state), then don't 878 * cluster with it. 879 */ 880 if (BUF_LOCK(tbp, 881 LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK, 882 BO_MTX(bo))) 883 break; 884 885 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 886 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 887 != (B_DELWRI | B_CLUSTEROK | 888 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 889 tbp->b_wcred != bp->b_wcred) { 890 BUF_UNLOCK(tbp); 891 break; 892 } 893 894 /* 895 * Check that the combined cluster 896 * would make sense with regard to pages 897 * and would not be too large 898 */ 899 if ((tbp->b_bcount != size) || 900 ((bp->b_blkno + (dbsize * i)) != 901 tbp->b_blkno) || 902 ((tbp->b_npages + bp->b_npages) > 903 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 904 BUF_UNLOCK(tbp); 905 break; 906 } 907 908 /* 909 * Do not pull in pinned buffers. 910 */ 911 if (tbp->b_pin_count > 0) { 912 BUF_UNLOCK(tbp); 913 break; 914 } 915 916 /* 917 * Ok, it's passed all the tests, 918 * so remove it from the free list 919 * and mark it busy. We will use it. 920 */ 921 bremfree(tbp); 922 tbp->b_flags &= ~B_DONE; 923 } /* end of code for non-first buffers only */ 924 /* 925 * If the IO is via the VM then we do some 926 * special VM hackery (yuck). Since the buffer's 927 * block size may not be page-aligned it is possible 928 * for a page to be shared between two buffers. We 929 * have to get rid of the duplication when building 930 * the cluster. 931 */ 932 if (tbp->b_flags & B_VMIO) { 933 vm_page_t m; 934 935 VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object); 936 if (i != 0) { /* if not first buffer */ 937 for (j = 0; j < tbp->b_npages; j += 1) { 938 m = tbp->b_pages[j]; 939 if (m->oflags & VPO_BUSY) { 940 VM_OBJECT_WUNLOCK( 941 tbp->b_object); 942 bqrelse(tbp); 943 goto finishcluster; 944 } 945 } 946 } 947 for (j = 0; j < tbp->b_npages; j += 1) { 948 m = tbp->b_pages[j]; 949 vm_page_io_start(m); 950 vm_object_pip_add(m->object, 1); 951 if ((bp->b_npages == 0) || 952 (bp->b_pages[bp->b_npages - 1] != m)) { 953 bp->b_pages[bp->b_npages] = m; 954 bp->b_npages++; 955 } 956 } 957 VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object); 958 } 959 bp->b_bcount += size; 960 bp->b_bufsize += size; 961 /* 962 * If any of the clustered buffers have their 963 * B_BARRIER flag set, transfer that request to 964 * the cluster. 965 */ 966 bp->b_flags |= (tbp->b_flags & B_BARRIER); 967 tbp->b_flags &= ~(B_DONE | B_BARRIER); 968 tbp->b_flags |= B_ASYNC; 969 tbp->b_ioflags &= ~BIO_ERROR; 970 tbp->b_iocmd = BIO_WRITE; 971 bundirty(tbp); 972 reassignbuf(tbp); /* put on clean list */ 973 bufobj_wref(tbp->b_bufobj); 974 BUF_KERNPROC(tbp); 975 TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, 976 tbp, b_cluster.cluster_entry); 977 } 978 finishcluster: 979 if ((bp->b_flags & B_UNMAPPED) == 0) { 980 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 981 (vm_page_t *)bp->b_pages, bp->b_npages); 982 } 983 if (bp->b_bufsize > bp->b_kvasize) 984 panic( 985 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 986 bp->b_bufsize, bp->b_kvasize); 987 bp->b_kvasize = bp->b_bufsize; 988 totalwritten += bp->b_bufsize; 989 bp->b_dirtyoff = 0; 990 bp->b_dirtyend = bp->b_bufsize; 991 bawrite(bp); 992 993 len -= i; 994 } 995 return totalwritten; 996 } 997 998 /* 999 * Collect together all the buffers in a cluster. 1000 * Plus add one additional buffer. 1001 */ 1002 static struct cluster_save * 1003 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int gbflags) 1004 { 1005 struct cluster_save *buflist; 1006 struct buf *bp; 1007 daddr_t lbn; 1008 int i, len; 1009 1010 len = vp->v_lastw - vp->v_cstart + 1; 1011 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 1012 M_SEGMENT, M_WAITOK); 1013 buflist->bs_nchildren = 0; 1014 buflist->bs_children = (struct buf **) (buflist + 1); 1015 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 1016 (void)bread_gb(vp, lbn, last_bp->b_bcount, NOCRED, 1017 gbflags, &bp); 1018 buflist->bs_children[i] = bp; 1019 if (bp->b_blkno == bp->b_lblkno) 1020 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, 1021 NULL, NULL); 1022 } 1023 buflist->bs_children[i] = bp = last_bp; 1024 if (bp->b_blkno == bp->b_lblkno) 1025 VOP_BMAP(vp, bp->b_lblkno, NULL, &bp->b_blkno, NULL, NULL); 1026 buflist->bs_nchildren = i + 1; 1027 return (buflist); 1028 } 1029