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 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)vfs_cluster.c 8.7 (Berkeley) 2/13/94 36 * $FreeBSD: src/sys/kern/vfs_cluster.c,v 1.92.2.9 2001/11/18 07:10:59 dillon Exp $ 37 * $DragonFly: src/sys/kern/vfs_cluster.c,v 1.25 2006/05/04 18:32:22 dillon Exp $ 38 */ 39 40 #include "opt_debug_cluster.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/kernel.h> 45 #include <sys/proc.h> 46 #include <sys/buf.h> 47 #include <sys/vnode.h> 48 #include <sys/malloc.h> 49 #include <sys/mount.h> 50 #include <sys/resourcevar.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 #include <sys/buf2.h> 57 #include <vm/vm_page2.h> 58 59 #if defined(CLUSTERDEBUG) 60 #include <sys/sysctl.h> 61 static int rcluster= 0; 62 SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0, ""); 63 #endif 64 65 static MALLOC_DEFINE(M_SEGMENT, "cluster_save", "cluster_save buffer"); 66 67 static struct cluster_save * 68 cluster_collectbufs (struct vnode *vp, struct buf *last_bp, 69 int lblocksize); 70 static struct buf * 71 cluster_rbuild (struct vnode *vp, off_t filesize, off_t loffset, 72 off_t doffset, int size, int run, 73 struct buf *fbp, int doasync); 74 static void cluster_callback (struct bio *); 75 76 77 static int write_behind = 1; 78 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, ""); 79 80 extern vm_page_t bogus_page; 81 82 extern int cluster_pbuf_freecnt; 83 84 /* 85 * Maximum number of blocks for read-ahead. 86 */ 87 #define MAXRA 32 88 89 /* 90 * This replaces bread. 91 */ 92 int 93 cluster_read(struct vnode *vp, off_t filesize, off_t loffset, 94 int size, int totread, int seqcount, struct buf **bpp) 95 { 96 struct buf *bp, *rbp, *reqbp; 97 off_t origoffset; 98 off_t doffset; 99 int error; 100 int i; 101 int maxra, racluster; 102 103 error = 0; 104 105 /* 106 * Try to limit the amount of read-ahead by a few 107 * ad-hoc parameters. This needs work!!! 108 */ 109 racluster = vp->v_mount->mnt_iosize_max / size; 110 maxra = 2 * racluster + (totread / size); 111 if (maxra > MAXRA) 112 maxra = MAXRA; 113 if (maxra > nbuf/8) 114 maxra = nbuf/8; 115 116 /* 117 * get the requested block 118 */ 119 *bpp = reqbp = bp = getblk(vp, loffset, size, 0, 0); 120 origoffset = loffset; 121 122 /* 123 * if it is in the cache, then check to see if the reads have been 124 * sequential. If they have, then try some read-ahead, otherwise 125 * back-off on prospective read-aheads. 126 */ 127 if (bp->b_flags & B_CACHE) { 128 if (!seqcount) { 129 return 0; 130 } else if ((bp->b_flags & B_RAM) == 0) { 131 return 0; 132 } else { 133 struct buf *tbp; 134 bp->b_flags &= ~B_RAM; 135 /* 136 * We do the crit here so that there is no window 137 * between the findblk and the b_usecount increment 138 * below. We opt to keep the crit out of the loop 139 * for efficiency. 140 */ 141 crit_enter(); 142 for (i = 1; i < maxra; i++) { 143 if (!(tbp = findblk(vp, loffset + i * size))) { 144 break; 145 } 146 147 /* 148 * Set another read-ahead mark so we know 149 * to check again. 150 */ 151 if (((i % racluster) == (racluster - 1)) || 152 (i == (maxra - 1))) 153 tbp->b_flags |= B_RAM; 154 } 155 crit_exit(); 156 if (i >= maxra) { 157 return 0; 158 } 159 loffset += i * size; 160 } 161 reqbp = bp = NULL; 162 } else { 163 off_t firstread = bp->b_loffset; 164 int nblks; 165 166 KASSERT(firstread != NOOFFSET, 167 ("cluster_read: no buffer offset")); 168 if (firstread + totread > filesize) 169 totread = (int)(filesize - firstread); 170 nblks = totread / size; 171 if (nblks) { 172 int burstbytes; 173 174 if (nblks > racluster) 175 nblks = racluster; 176 177 error = VOP_BMAP(vp, loffset, NULL, 178 &doffset, &burstbytes, NULL); 179 if (error) 180 goto single_block_read; 181 if (doffset == NOOFFSET) 182 goto single_block_read; 183 if (burstbytes < size * 2) 184 goto single_block_read; 185 if (nblks > burstbytes / size) 186 nblks = burstbytes / size; 187 188 bp = cluster_rbuild(vp, filesize, loffset, 189 doffset, size, nblks, bp, 0); 190 loffset += bp->b_bufsize; 191 } else { 192 single_block_read: 193 /* 194 * if it isn't in the cache, then get a chunk from 195 * disk if sequential, otherwise just get the block. 196 */ 197 bp->b_flags |= B_RAM; 198 loffset += size; 199 } 200 } 201 202 /* 203 * If we have been doing sequential I/O, then do some read-ahead. 204 */ 205 rbp = NULL; 206 if (seqcount && 207 loffset < origoffset + seqcount * size && 208 loffset + size <= filesize 209 ) { 210 rbp = getblk(vp, loffset, size, 0, 0); 211 if ((rbp->b_flags & B_CACHE) == 0) { 212 int nblksread; 213 int ntoread; 214 int burstbytes; 215 216 error = VOP_BMAP(vp, loffset, NULL, 217 &doffset, &burstbytes, NULL); 218 if (error || doffset == NOOFFSET) { 219 brelse(rbp); 220 rbp = NULL; 221 goto no_read_ahead; 222 } 223 ntoread = burstbytes / size; 224 nblksread = (totread + size - 1) / size; 225 if (seqcount < nblksread) 226 seqcount = nblksread; 227 if (seqcount < ntoread) 228 ntoread = seqcount; 229 230 rbp->b_flags |= B_RAM; 231 if (burstbytes) { 232 rbp = cluster_rbuild(vp, filesize, loffset, 233 doffset, size, 234 ntoread, rbp, 1); 235 } else { 236 rbp->b_bio2.bio_offset = doffset; 237 } 238 } 239 } 240 no_read_ahead: 241 242 /* 243 * Handle the synchronous read. This only occurs if B_CACHE was 244 * not set. bp (and rbp) could be either a cluster bp or a normal 245 * bp depending on the what cluster_rbuild() decided to do. If 246 * it is a cluster bp, vfs_busy_pages() has already been called. 247 */ 248 if (bp) { 249 #if defined(CLUSTERDEBUG) 250 if (rcluster) 251 printf("S(%lld,%d,%d) ", 252 bp->b_loffset, bp->b_bcount, seqcount); 253 #endif 254 bp->b_cmd = BUF_CMD_READ; 255 if ((bp->b_flags & B_CLUSTER) == 0) 256 vfs_busy_pages(vp, bp); 257 bp->b_flags &= ~(B_ERROR|B_INVAL); 258 if ((bp->b_flags & B_ASYNC) || bp->b_bio1.bio_done != NULL) 259 BUF_KERNPROC(bp); 260 vn_strategy(vp, &bp->b_bio1); 261 error = bp->b_error; 262 } 263 264 /* 265 * And if we have read-aheads, do them too. 266 */ 267 if (rbp) { 268 if (error) { 269 brelse(rbp); 270 } else if (rbp->b_flags & B_CACHE) { 271 bqrelse(rbp); 272 } else { 273 #if defined(CLUSTERDEBUG) 274 if (rcluster) { 275 if (bp) 276 printf("A+(%lld,%d,%lld,%d) ", 277 rbp->b_loffset, rbp->b_bcount, 278 rbp->b_loffset - origoffset, 279 seqcount); 280 else 281 printf("A(%lld,%d,%lld,%d) ", 282 rbp->b_loffset, rbp->b_bcount, 283 rbp->b_loffset - origoffset, 284 seqcount); 285 } 286 #endif 287 rbp->b_flags &= ~(B_ERROR|B_INVAL); 288 rbp->b_flags |= B_ASYNC; 289 rbp->b_cmd = BUF_CMD_READ; 290 291 if ((rbp->b_flags & B_CLUSTER) == 0) 292 vfs_busy_pages(vp, rbp); 293 if ((rbp->b_flags & B_ASYNC) || rbp->b_bio1.bio_done != NULL) 294 BUF_KERNPROC(rbp); 295 vn_strategy(vp, &rbp->b_bio1); 296 } 297 } 298 if (reqbp) 299 return (biowait(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, off_t filesize, off_t loffset, 311 off_t doffset, int size, int run, struct buf *fbp, int doasync) 312 { 313 struct buf *bp, *tbp; 314 off_t boffset; 315 int i, j; 316 317 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 318 ("cluster_rbuild: size %d != filesize %ld\n", 319 size, vp->v_mount->mnt_stat.f_iosize)); 320 321 /* 322 * avoid a division 323 */ 324 while (loffset + run * size > filesize) { 325 --run; 326 } 327 328 tbp = fbp; 329 tbp->b_bio2.bio_offset = doffset; 330 if((tbp->b_flags & B_MALLOC) || 331 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) { 332 return tbp; 333 } 334 335 bp = trypbuf(&cluster_pbuf_freecnt); 336 if (bp == NULL) 337 return tbp; 338 339 /* 340 * We are synthesizing a buffer out of vm_page_t's, but 341 * if the block size is not page aligned then the starting 342 * address may not be either. Inherit the b_data offset 343 * from the original buffer. 344 */ 345 bp->b_data = (char *)((vm_offset_t)bp->b_data | 346 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 347 bp->b_flags |= B_ASYNC | B_CLUSTER | B_VMIO; 348 bp->b_cmd = BUF_CMD_READ; 349 bp->b_bio1.bio_done = cluster_callback; 350 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 351 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 352 bp->b_loffset = loffset; 353 bp->b_bio2.bio_offset = NOOFFSET; 354 KASSERT(bp->b_loffset != NOOFFSET, 355 ("cluster_rbuild: no buffer offset")); 356 357 bp->b_bcount = 0; 358 bp->b_bufsize = 0; 359 bp->b_xio.xio_npages = 0; 360 361 for (boffset = doffset, i = 0; i < run; ++i, boffset += size) { 362 if (i) { 363 if ((bp->b_xio.xio_npages * PAGE_SIZE) + 364 round_page(size) > vp->v_mount->mnt_iosize_max) { 365 break; 366 } 367 368 /* 369 * Shortcut some checks and try to avoid buffers that 370 * would block in the lock. The same checks have to 371 * be made again after we officially get the buffer. 372 */ 373 if ((tbp = findblk(vp, loffset + i * size)) != NULL) { 374 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) 375 break; 376 BUF_UNLOCK(tbp); 377 378 for (j = 0; j < tbp->b_xio.xio_npages; j++) { 379 if (tbp->b_xio.xio_pages[j]->valid) 380 break; 381 } 382 383 if (j != tbp->b_xio.xio_npages) 384 break; 385 386 if (tbp->b_bcount != size) 387 break; 388 } 389 390 tbp = getblk(vp, loffset + i * size, size, 0, 0); 391 392 /* 393 * Stop scanning if the buffer is fuly valid 394 * (marked B_CACHE), or locked (may be doing a 395 * background write), or if the buffer is not 396 * VMIO backed. The clustering code can only deal 397 * with VMIO-backed buffers. 398 */ 399 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || 400 (tbp->b_flags & B_VMIO) == 0) { 401 bqrelse(tbp); 402 break; 403 } 404 405 /* 406 * The buffer must be completely invalid in order to 407 * take part in the cluster. If it is partially valid 408 * then we stop. 409 */ 410 for (j = 0;j < tbp->b_xio.xio_npages; j++) { 411 if (tbp->b_xio.xio_pages[j]->valid) 412 break; 413 } 414 if (j != tbp->b_xio.xio_npages) { 415 bqrelse(tbp); 416 break; 417 } 418 419 /* 420 * Set a read-ahead mark as appropriate 421 */ 422 if (i == 1 || i == (run - 1)) 423 tbp->b_flags |= B_RAM; 424 425 /* 426 * Set the block number if it isn't set, otherwise 427 * if it is make sure it matches the block number we 428 * expect. 429 */ 430 if (tbp->b_bio2.bio_offset == NOOFFSET) { 431 tbp->b_bio2.bio_offset = boffset; 432 } else if (tbp->b_bio2.bio_offset != boffset) { 433 brelse(tbp); 434 break; 435 } 436 } 437 /* 438 * The first buffer is setup async if doasync is specified. 439 * All other buffers in the cluster are setup async. This 440 * way the caller can decide how to deal with the requested 441 * buffer. 442 */ 443 if (i || doasync) 444 tbp->b_flags |= B_ASYNC; 445 tbp->b_cmd = BUF_CMD_READ; 446 BUF_KERNPROC(tbp); 447 cluster_append(&bp->b_bio1, tbp); 448 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 449 vm_page_t m; 450 m = tbp->b_xio.xio_pages[j]; 451 vm_page_io_start(m); 452 vm_object_pip_add(m->object, 1); 453 if ((bp->b_xio.xio_npages == 0) || 454 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) { 455 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 456 bp->b_xio.xio_npages++; 457 } 458 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 459 tbp->b_xio.xio_pages[j] = bogus_page; 460 } 461 /* 462 * XXX shouldn't this be += size for both, like in 463 * cluster_wbuild()? 464 * 465 * Don't inherit tbp->b_bufsize as it may be larger due to 466 * a non-page-aligned size. Instead just aggregate using 467 * 'size'. 468 */ 469 if (tbp->b_bcount != size) 470 printf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, size); 471 if (tbp->b_bufsize != size) 472 printf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, size); 473 bp->b_bcount += size; 474 bp->b_bufsize += size; 475 } 476 477 /* 478 * Fully valid pages in the cluster are already good and do not need 479 * to be re-read from disk. Replace the page with bogus_page 480 */ 481 for (j = 0; j < bp->b_xio.xio_npages; j++) { 482 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) == 483 VM_PAGE_BITS_ALL) { 484 bp->b_xio.xio_pages[j] = bogus_page; 485 } 486 } 487 if (bp->b_bufsize > bp->b_kvasize) { 488 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)", 489 bp->b_bufsize, bp->b_kvasize); 490 } 491 492 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 493 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages); 494 return (bp); 495 } 496 497 /* 498 * Cleanup after a clustered read or write. 499 * This is complicated by the fact that any of the buffers might have 500 * extra memory (if there were no empty buffer headers at allocbuf time) 501 * that we will need to shift around. 502 * 503 * The returned bio is &bp->b_bio1 504 */ 505 void 506 cluster_callback(struct bio *bio) 507 { 508 struct buf *bp = bio->bio_buf; 509 struct buf *tbp; 510 int error = 0; 511 512 /* 513 * Must propogate errors to all the components. A short read (EOF) 514 * is a critical error. 515 */ 516 if (bp->b_flags & B_ERROR) { 517 error = bp->b_error; 518 } else if (bp->b_bcount != bp->b_bufsize) { 519 panic("cluster_callback: unexpected EOF on cluster %p!", bio); 520 } 521 522 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages); 523 /* 524 * Move memory from the large cluster buffer into the component 525 * buffers and mark IO as done on these. Since the memory map 526 * is the same, no actual copying is required. 527 */ 528 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) { 529 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next; 530 if (error) { 531 tbp->b_flags |= B_ERROR; 532 tbp->b_error = error; 533 } else { 534 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 535 tbp->b_flags &= ~(B_ERROR|B_INVAL); 536 /* 537 * XXX the bdwrite()/bqrelse() issued during 538 * cluster building clears B_RELBUF (see bqrelse() 539 * comment). If direct I/O was specified, we have 540 * to restore it here to allow the buffer and VM 541 * to be freed. 542 */ 543 if (tbp->b_flags & B_DIRECT) 544 tbp->b_flags |= B_RELBUF; 545 } 546 biodone(&tbp->b_bio1); 547 } 548 relpbuf(bp, &cluster_pbuf_freecnt); 549 } 550 551 /* 552 * cluster_wbuild_wb: 553 * 554 * Implement modified write build for cluster. 555 * 556 * write_behind = 0 write behind disabled 557 * write_behind = 1 write behind normal (default) 558 * write_behind = 2 write behind backed-off 559 */ 560 561 static __inline int 562 cluster_wbuild_wb(struct vnode *vp, int size, off_t start_loffset, int len) 563 { 564 int r = 0; 565 566 switch(write_behind) { 567 case 2: 568 if (start_loffset < len) 569 break; 570 start_loffset -= len; 571 /* fall through */ 572 case 1: 573 r = cluster_wbuild(vp, size, start_loffset, len); 574 /* fall through */ 575 default: 576 /* fall through */ 577 break; 578 } 579 return(r); 580 } 581 582 /* 583 * Do clustered write for FFS. 584 * 585 * Three cases: 586 * 1. Write is not sequential (write asynchronously) 587 * Write is sequential: 588 * 2. beginning of cluster - begin cluster 589 * 3. middle of a cluster - add to cluster 590 * 4. end of a cluster - asynchronously write cluster 591 */ 592 void 593 cluster_write(struct buf *bp, off_t filesize, int seqcount) 594 { 595 struct vnode *vp; 596 off_t loffset; 597 int maxclen, cursize; 598 int lblocksize; 599 int async; 600 601 vp = bp->b_vp; 602 if (vp->v_type == VREG) { 603 async = vp->v_mount->mnt_flag & MNT_ASYNC; 604 lblocksize = vp->v_mount->mnt_stat.f_iosize; 605 } else { 606 async = 0; 607 lblocksize = bp->b_bufsize; 608 } 609 loffset = bp->b_loffset; 610 KASSERT(bp->b_loffset != NOOFFSET, 611 ("cluster_write: no buffer offset")); 612 613 /* Initialize vnode to beginning of file. */ 614 if (loffset == 0) 615 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 616 617 if (vp->v_clen == 0 || loffset != vp->v_lastw + lblocksize || 618 bp->b_bio2.bio_offset == NOOFFSET || 619 (bp->b_bio2.bio_offset != vp->v_lasta + lblocksize)) { 620 maxclen = vp->v_mount->mnt_iosize_max; 621 if (vp->v_clen != 0) { 622 /* 623 * Next block is not sequential. 624 * 625 * If we are not writing at end of file, the process 626 * seeked to another point in the file since its last 627 * write, or we have reached our maximum cluster size, 628 * then push the previous cluster. Otherwise try 629 * reallocating to make it sequential. 630 * 631 * Change to algorithm: only push previous cluster if 632 * it was sequential from the point of view of the 633 * seqcount heuristic, otherwise leave the buffer 634 * intact so we can potentially optimize the I/O 635 * later on in the buf_daemon or update daemon 636 * flush. 637 */ 638 cursize = vp->v_lastw - vp->v_cstart + lblocksize; 639 if (bp->b_loffset + lblocksize != filesize || 640 loffset != vp->v_lastw + lblocksize || vp->v_clen <= cursize) { 641 if (!async && seqcount > 0) { 642 cluster_wbuild_wb(vp, lblocksize, 643 vp->v_cstart, cursize); 644 } 645 } else { 646 struct buf **bpp, **endbp; 647 struct cluster_save *buflist; 648 649 buflist = cluster_collectbufs(vp, bp, 650 lblocksize); 651 endbp = &buflist->bs_children 652 [buflist->bs_nchildren - 1]; 653 if (VOP_REALLOCBLKS(vp, buflist)) { 654 /* 655 * Failed, push the previous cluster 656 * if *really* writing sequentially 657 * in the logical file (seqcount > 1), 658 * otherwise delay it in the hopes that 659 * the low level disk driver can 660 * optimize the write ordering. 661 */ 662 for (bpp = buflist->bs_children; 663 bpp < endbp; bpp++) 664 brelse(*bpp); 665 free(buflist, M_SEGMENT); 666 if (seqcount > 1) { 667 cluster_wbuild_wb(vp, 668 lblocksize, vp->v_cstart, 669 cursize); 670 } 671 } else { 672 /* 673 * Succeeded, keep building cluster. 674 */ 675 for (bpp = buflist->bs_children; 676 bpp <= endbp; bpp++) 677 bdwrite(*bpp); 678 free(buflist, M_SEGMENT); 679 vp->v_lastw = loffset; 680 vp->v_lasta = bp->b_bio2.bio_offset; 681 return; 682 } 683 } 684 } 685 /* 686 * Consider beginning a cluster. If at end of file, make 687 * cluster as large as possible, otherwise find size of 688 * existing cluster. 689 */ 690 if ((vp->v_type == VREG) && 691 bp->b_loffset + lblocksize != filesize && 692 (bp->b_bio2.bio_offset == NOOFFSET) && 693 (VOP_BMAP(vp, loffset, NULL, &bp->b_bio2.bio_offset, &maxclen, NULL) || 694 bp->b_bio2.bio_offset == NOOFFSET)) { 695 bawrite(bp); 696 vp->v_clen = 0; 697 vp->v_lasta = bp->b_bio2.bio_offset; 698 vp->v_cstart = loffset + lblocksize; 699 vp->v_lastw = loffset; 700 return; 701 } 702 if (maxclen > lblocksize) 703 vp->v_clen = maxclen - lblocksize; 704 else 705 vp->v_clen = 0; 706 if (!async && vp->v_clen == 0) { /* I/O not contiguous */ 707 vp->v_cstart = loffset + lblocksize; 708 bawrite(bp); 709 } else { /* Wait for rest of cluster */ 710 vp->v_cstart = loffset; 711 bdwrite(bp); 712 } 713 } else if (loffset == vp->v_cstart + vp->v_clen) { 714 /* 715 * At end of cluster, write it out if seqcount tells us we 716 * are operating sequentially, otherwise let the buf or 717 * update daemon handle it. 718 */ 719 bdwrite(bp); 720 if (seqcount > 1) 721 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, 722 vp->v_clen + lblocksize); 723 vp->v_clen = 0; 724 vp->v_cstart = loffset + lblocksize; 725 } else if (vm_page_count_severe()) { 726 /* 727 * We are low on memory, get it going NOW 728 */ 729 bawrite(bp); 730 } else { 731 /* 732 * In the middle of a cluster, so just delay the I/O for now. 733 */ 734 bdwrite(bp); 735 } 736 vp->v_lastw = loffset; 737 vp->v_lasta = bp->b_bio2.bio_offset; 738 } 739 740 741 /* 742 * This is an awful lot like cluster_rbuild...wish they could be combined. 743 * The last lbn argument is the current block on which I/O is being 744 * performed. Check to see that it doesn't fall in the middle of 745 * the current block (if last_bp == NULL). 746 */ 747 int 748 cluster_wbuild(struct vnode *vp, int size, off_t start_loffset, int bytes) 749 { 750 struct buf *bp, *tbp; 751 int i, j; 752 int totalwritten = 0; 753 754 while (bytes > 0) { 755 crit_enter(); 756 /* 757 * If the buffer is not delayed-write (i.e. dirty), or it 758 * is delayed-write but either locked or inval, it cannot 759 * partake in the clustered write. 760 */ 761 if (((tbp = findblk(vp, start_loffset)) == NULL) || 762 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 763 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 764 start_loffset += size; 765 bytes -= size; 766 crit_exit(); 767 continue; 768 } 769 bremfree(tbp); 770 KKASSERT(tbp->b_cmd == BUF_CMD_DONE); 771 crit_exit(); 772 773 /* 774 * Extra memory in the buffer, punt on this buffer. 775 * XXX we could handle this in most cases, but we would 776 * have to push the extra memory down to after our max 777 * possible cluster size and then potentially pull it back 778 * up if the cluster was terminated prematurely--too much 779 * hassle. 780 */ 781 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 782 (tbp->b_bcount != tbp->b_bufsize) || 783 (tbp->b_bcount != size) || 784 (bytes == size) || 785 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 786 totalwritten += tbp->b_bufsize; 787 bawrite(tbp); 788 start_loffset += size; 789 bytes -= size; 790 continue; 791 } 792 793 /* 794 * Set up the pbuf. Track our append point with b_bcount 795 * and b_bufsize. b_bufsize is not used by the device but 796 * our caller uses it to loop clusters and we use it to 797 * detect a premature EOF on the block device. 798 */ 799 bp->b_bcount = 0; 800 bp->b_bufsize = 0; 801 bp->b_xio.xio_npages = 0; 802 bp->b_loffset = tbp->b_loffset; 803 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset; 804 805 /* 806 * We are synthesizing a buffer out of vm_page_t's, but 807 * if the block size is not page aligned then the starting 808 * address may not be either. Inherit the b_data offset 809 * from the original buffer. 810 */ 811 bp->b_data = (char *)((vm_offset_t)bp->b_data | 812 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 813 bp->b_flags &= ~B_ERROR; 814 bp->b_flags |= B_CLUSTER | B_BNOCLIP | 815 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN)); 816 bp->b_bio1.bio_done = cluster_callback; 817 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 818 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 819 /* 820 * From this location in the file, scan forward to see 821 * if there are buffers with adjacent data that need to 822 * be written as well. 823 */ 824 for (i = 0; i < bytes; (i += size), (start_loffset += size)) { 825 if (i != 0) { /* If not the first buffer */ 826 crit_enter(); 827 /* 828 * If the adjacent data is not even in core it 829 * can't need to be written. 830 */ 831 if ((tbp = findblk(vp, start_loffset)) == NULL) { 832 crit_exit(); 833 break; 834 } 835 836 /* 837 * If it IS in core, but has different 838 * characteristics, or is locked (which 839 * means it could be undergoing a background 840 * I/O or be in a weird state), then don't 841 * cluster with it. 842 */ 843 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 844 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 845 != (B_DELWRI | B_CLUSTEROK | 846 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 847 (tbp->b_flags & B_LOCKED) || 848 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 849 crit_exit(); 850 break; 851 } 852 853 /* 854 * Check that the combined cluster 855 * would make sense with regard to pages 856 * and would not be too large 857 */ 858 if ((tbp->b_bcount != size) || 859 ((bp->b_bio2.bio_offset + i) != 860 tbp->b_bio2.bio_offset) || 861 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) > 862 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 863 BUF_UNLOCK(tbp); 864 crit_exit(); 865 break; 866 } 867 /* 868 * Ok, it's passed all the tests, 869 * so remove it from the free list 870 * and mark it busy. We will use it. 871 */ 872 bremfree(tbp); 873 KKASSERT(tbp->b_cmd == BUF_CMD_DONE); 874 crit_exit(); 875 } /* end of code for non-first buffers only */ 876 877 /* 878 * If the IO is via the VM then we do some 879 * special VM hackery (yuck). Since the buffer's 880 * block size may not be page-aligned it is possible 881 * for a page to be shared between two buffers. We 882 * have to get rid of the duplication when building 883 * the cluster. 884 */ 885 if (tbp->b_flags & B_VMIO) { 886 vm_page_t m; 887 888 if (i != 0) { /* if not first buffer */ 889 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 890 m = tbp->b_xio.xio_pages[j]; 891 if (m->flags & PG_BUSY) { 892 bqrelse(tbp); 893 goto finishcluster; 894 } 895 } 896 } 897 898 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 899 m = tbp->b_xio.xio_pages[j]; 900 vm_page_io_start(m); 901 vm_object_pip_add(m->object, 1); 902 if ((bp->b_xio.xio_npages == 0) || 903 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) { 904 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 905 bp->b_xio.xio_npages++; 906 } 907 } 908 } 909 bp->b_bcount += size; 910 bp->b_bufsize += size; 911 912 crit_enter(); 913 bundirty(tbp); 914 tbp->b_flags &= ~B_ERROR; 915 tbp->b_flags |= B_ASYNC; 916 tbp->b_cmd = BUF_CMD_WRITE; 917 crit_exit(); 918 BUF_KERNPROC(tbp); 919 cluster_append(&bp->b_bio1, tbp); 920 921 /* 922 * check for latent dependencies to be handled 923 */ 924 if (LIST_FIRST(&tbp->b_dep) != NULL && bioops.io_start) 925 (*bioops.io_start)(tbp); 926 927 } 928 finishcluster: 929 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 930 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages); 931 if (bp->b_bufsize > bp->b_kvasize) { 932 panic( 933 "cluster_wbuild: b_bufsize(%d) > b_kvasize(%d)\n", 934 bp->b_bufsize, bp->b_kvasize); 935 } 936 totalwritten += bp->b_bufsize; 937 bp->b_dirtyoff = 0; 938 bp->b_dirtyend = bp->b_bufsize; 939 bp->b_flags |= B_ASYNC; 940 bp->b_cmd = BUF_CMD_WRITE; 941 vfs_busy_pages(vp, bp); 942 bp->b_runningbufspace = bp->b_bufsize; 943 runningbufspace += bp->b_runningbufspace; 944 BUF_KERNPROC(bp); /* B_ASYNC */ 945 vn_strategy(vp, &bp->b_bio1); 946 947 bytes -= i; 948 } 949 return totalwritten; 950 } 951 952 /* 953 * Collect together all the buffers in a cluster. 954 * Plus add one additional buffer. 955 */ 956 static struct cluster_save * 957 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int lblocksize) 958 { 959 struct cluster_save *buflist; 960 struct buf *bp; 961 off_t loffset; 962 int i, len; 963 964 len = (int)(vp->v_lastw - vp->v_cstart + lblocksize) / lblocksize; 965 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 966 M_SEGMENT, M_WAITOK); 967 buflist->bs_nchildren = 0; 968 buflist->bs_children = (struct buf **) (buflist + 1); 969 for (loffset = vp->v_cstart, i = 0; i < len; (loffset += lblocksize), i++) { 970 (void) bread(vp, loffset, last_bp->b_bcount, &bp); 971 buflist->bs_children[i] = bp; 972 if (bp->b_bio2.bio_offset == NOOFFSET) { 973 VOP_BMAP(bp->b_vp, bp->b_loffset, NULL, 974 &bp->b_bio2.bio_offset, NULL, NULL); 975 } 976 } 977 buflist->bs_children[i] = bp = last_bp; 978 if (bp->b_bio2.bio_offset == NOOFFSET) { 979 VOP_BMAP(bp->b_vp, bp->b_loffset, NULL, 980 &bp->b_bio2.bio_offset, NULL, NULL); 981 } 982 buflist->bs_nchildren = i + 1; 983 return (buflist); 984 } 985 986 void 987 cluster_append(struct bio *bio, struct buf *tbp) 988 { 989 tbp->b_cluster_next = NULL; 990 if (bio->bio_caller_info1.cluster_head == NULL) { 991 bio->bio_caller_info1.cluster_head = tbp; 992 bio->bio_caller_info2.cluster_tail = tbp; 993 } else { 994 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp; 995 bio->bio_caller_info2.cluster_tail = tbp; 996 } 997 } 998 999