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 1.33 2008/04/22 18:46:51 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, 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 * Handle the synchronous read. This only occurs if B_CACHE was 204 * not set. bp (and rbp) could be either a cluster bp or a normal 205 * bp depending on the what cluster_rbuild() decided to do. If 206 * it is a cluster bp, vfs_busy_pages() has already been called. 207 */ 208 if (bp) { 209 #if defined(CLUSTERDEBUG) 210 if (rcluster) 211 kprintf("S(%lld,%d,%d) ", 212 bp->b_loffset, bp->b_bcount, seqcount); 213 #endif 214 bp->b_cmd = BUF_CMD_READ; 215 if ((bp->b_flags & B_CLUSTER) == 0) 216 vfs_busy_pages(vp, bp); 217 bp->b_flags &= ~(B_ERROR|B_INVAL); 218 if ((bp->b_flags & B_ASYNC) || bp->b_bio1.bio_done != NULL) 219 BUF_KERNPROC(bp); 220 vn_strategy(vp, &bp->b_bio1); 221 error = bp->b_error; 222 } 223 224 /* 225 * If we have been doing sequential I/O, then do some read-ahead. 226 */ 227 rbp = NULL; 228 if (!error && 229 seqcount && 230 loffset < origoffset + seqcount * size && 231 loffset + size <= filesize 232 ) { 233 int nblksread; 234 int ntoread; 235 int burstbytes; 236 237 rbp = getblk(vp, loffset, size, 0, 0); 238 if ((rbp->b_flags & B_CACHE)) { 239 bqrelse(rbp); 240 goto no_read_ahead; 241 } 242 243 error = VOP_BMAP(vp, loffset, 244 &doffset, &burstbytes, NULL); 245 if (error || doffset == NOOFFSET) { 246 rbp->b_flags |= B_INVAL; 247 brelse(rbp); 248 rbp = NULL; 249 goto no_read_ahead; 250 } 251 ntoread = burstbytes / size; 252 nblksread = (totread + size - 1) / size; 253 if (seqcount < nblksread) 254 seqcount = nblksread; 255 if (seqcount < ntoread) 256 ntoread = seqcount; 257 258 rbp->b_flags |= B_RAM; 259 if (burstbytes) { 260 rbp = cluster_rbuild(vp, filesize, loffset, 261 doffset, size, 262 ntoread, rbp, 1); 263 } else { 264 rbp->b_bio2.bio_offset = doffset; 265 } 266 #if defined(CLUSTERDEBUG) 267 if (rcluster) { 268 if (bp) 269 kprintf("A+(%lld,%d,%lld,%d) ", 270 rbp->b_loffset, rbp->b_bcount, 271 rbp->b_loffset - origoffset, 272 seqcount); 273 else 274 kprintf("A(%lld,%d,%lld,%d) ", 275 rbp->b_loffset, rbp->b_bcount, 276 rbp->b_loffset - origoffset, 277 seqcount); 278 } 279 #endif 280 rbp->b_flags &= ~(B_ERROR|B_INVAL); 281 rbp->b_flags |= B_ASYNC; 282 rbp->b_cmd = BUF_CMD_READ; 283 284 if ((rbp->b_flags & B_CLUSTER) == 0) 285 vfs_busy_pages(vp, rbp); 286 BUF_KERNPROC(rbp); /* B_ASYNC */ 287 vn_strategy(vp, &rbp->b_bio1); 288 } 289 no_read_ahead: 290 291 if (reqbp) 292 return (biowait(reqbp)); 293 else 294 return (error); 295 } 296 297 /* 298 * If blocks are contiguous on disk, use this to provide clustered 299 * read ahead. We will read as many blocks as possible sequentially 300 * and then parcel them up into logical blocks in the buffer hash table. 301 */ 302 static struct buf * 303 cluster_rbuild(struct vnode *vp, off_t filesize, off_t loffset, 304 off_t doffset, int size, int run, struct buf *fbp, int doasync) 305 { 306 struct buf *bp, *tbp; 307 off_t boffset; 308 int i, j; 309 310 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 311 ("cluster_rbuild: size %d != filesize %ld\n", 312 size, vp->v_mount->mnt_stat.f_iosize)); 313 314 /* 315 * avoid a division 316 */ 317 while (loffset + run * size > filesize) { 318 --run; 319 } 320 321 tbp = fbp; 322 tbp->b_bio2.bio_offset = doffset; 323 if((tbp->b_flags & B_MALLOC) || 324 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) { 325 return tbp; 326 } 327 328 bp = trypbuf(&cluster_pbuf_freecnt); 329 if (bp == NULL) 330 return tbp; 331 332 /* 333 * We are synthesizing a buffer out of vm_page_t's, but 334 * if the block size is not page aligned then the starting 335 * address may not be either. Inherit the b_data offset 336 * from the original buffer. 337 */ 338 bp->b_data = (char *)((vm_offset_t)bp->b_data | 339 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 340 bp->b_flags |= B_ASYNC | B_CLUSTER | B_VMIO; 341 bp->b_cmd = BUF_CMD_READ; 342 bp->b_bio1.bio_done = cluster_callback; 343 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 344 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 345 bp->b_loffset = loffset; 346 bp->b_bio2.bio_offset = NOOFFSET; 347 KASSERT(bp->b_loffset != NOOFFSET, 348 ("cluster_rbuild: no buffer offset")); 349 350 bp->b_bcount = 0; 351 bp->b_bufsize = 0; 352 bp->b_xio.xio_npages = 0; 353 354 for (boffset = doffset, i = 0; i < run; ++i, boffset += size) { 355 if (i) { 356 if ((bp->b_xio.xio_npages * PAGE_SIZE) + 357 round_page(size) > vp->v_mount->mnt_iosize_max) { 358 break; 359 } 360 361 /* 362 * Shortcut some checks and try to avoid buffers that 363 * would block in the lock. The same checks have to 364 * be made again after we officially get the buffer. 365 */ 366 if ((tbp = findblk(vp, loffset + i * size)) != NULL) { 367 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) 368 break; 369 BUF_UNLOCK(tbp); 370 371 for (j = 0; j < tbp->b_xio.xio_npages; j++) { 372 if (tbp->b_xio.xio_pages[j]->valid) 373 break; 374 } 375 376 if (j != tbp->b_xio.xio_npages) 377 break; 378 379 if (tbp->b_bcount != size) 380 break; 381 } 382 383 tbp = getblk(vp, loffset + i * size, size, 0, 0); 384 385 /* 386 * Stop scanning if the buffer is fuly valid 387 * (marked B_CACHE), or locked (may be doing a 388 * background write), or if the buffer is not 389 * VMIO backed. The clustering code can only deal 390 * with VMIO-backed buffers. 391 */ 392 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || 393 (tbp->b_flags & B_VMIO) == 0 || 394 (LIST_FIRST(&tbp->b_dep) != NULL && 395 buf_checkread(tbp)) 396 ) { 397 bqrelse(tbp); 398 break; 399 } 400 401 /* 402 * The buffer must be completely invalid in order to 403 * take part in the cluster. If it is partially valid 404 * then we stop. 405 */ 406 for (j = 0;j < tbp->b_xio.xio_npages; j++) { 407 if (tbp->b_xio.xio_pages[j]->valid) 408 break; 409 } 410 if (j != tbp->b_xio.xio_npages) { 411 bqrelse(tbp); 412 break; 413 } 414 415 /* 416 * Set a read-ahead mark as appropriate 417 */ 418 if (i == 1 || i == (run - 1)) 419 tbp->b_flags |= B_RAM; 420 421 /* 422 * Set the block number if it isn't set, otherwise 423 * if it is make sure it matches the block number we 424 * expect. 425 */ 426 if (tbp->b_bio2.bio_offset == NOOFFSET) { 427 tbp->b_bio2.bio_offset = boffset; 428 } else if (tbp->b_bio2.bio_offset != boffset) { 429 brelse(tbp); 430 break; 431 } 432 } 433 /* 434 * The first buffer is setup async if doasync is specified. 435 * All other buffers in the cluster are setup async. This 436 * way the caller can decide how to deal with the requested 437 * buffer. 438 */ 439 if (i || doasync) 440 tbp->b_flags |= B_ASYNC; 441 tbp->b_cmd = BUF_CMD_READ; 442 BUF_KERNPROC(tbp); 443 cluster_append(&bp->b_bio1, tbp); 444 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 445 vm_page_t m; 446 m = tbp->b_xio.xio_pages[j]; 447 vm_page_io_start(m); 448 vm_object_pip_add(m->object, 1); 449 if ((bp->b_xio.xio_npages == 0) || 450 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) { 451 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 452 bp->b_xio.xio_npages++; 453 } 454 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 455 tbp->b_xio.xio_pages[j] = bogus_page; 456 } 457 /* 458 * XXX shouldn't this be += size for both, like in 459 * cluster_wbuild()? 460 * 461 * Don't inherit tbp->b_bufsize as it may be larger due to 462 * a non-page-aligned size. Instead just aggregate using 463 * 'size'. 464 */ 465 if (tbp->b_bcount != size) 466 kprintf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, size); 467 if (tbp->b_bufsize != size) 468 kprintf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, size); 469 bp->b_bcount += size; 470 bp->b_bufsize += size; 471 } 472 473 /* 474 * Fully valid pages in the cluster are already good and do not need 475 * to be re-read from disk. Replace the page with bogus_page 476 */ 477 for (j = 0; j < bp->b_xio.xio_npages; j++) { 478 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) == 479 VM_PAGE_BITS_ALL) { 480 bp->b_xio.xio_pages[j] = bogus_page; 481 } 482 } 483 if (bp->b_bufsize > bp->b_kvasize) { 484 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)", 485 bp->b_bufsize, bp->b_kvasize); 486 } 487 488 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 489 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages); 490 return (bp); 491 } 492 493 /* 494 * Cleanup after a clustered read or write. 495 * This is complicated by the fact that any of the buffers might have 496 * extra memory (if there were no empty buffer headers at allocbuf time) 497 * that we will need to shift around. 498 * 499 * The returned bio is &bp->b_bio1 500 */ 501 void 502 cluster_callback(struct bio *bio) 503 { 504 struct buf *bp = bio->bio_buf; 505 struct buf *tbp; 506 int error = 0; 507 508 /* 509 * Must propogate errors to all the components. A short read (EOF) 510 * is a critical error. 511 */ 512 if (bp->b_flags & B_ERROR) { 513 error = bp->b_error; 514 } else if (bp->b_bcount != bp->b_bufsize) { 515 panic("cluster_callback: unexpected EOF on cluster %p!", bio); 516 } 517 518 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages); 519 /* 520 * Move memory from the large cluster buffer into the component 521 * buffers and mark IO as done on these. Since the memory map 522 * is the same, no actual copying is required. 523 */ 524 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) { 525 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next; 526 if (error) { 527 tbp->b_flags |= B_ERROR; 528 tbp->b_error = error; 529 } else { 530 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 531 tbp->b_flags &= ~(B_ERROR|B_INVAL); 532 /* 533 * XXX the bdwrite()/bqrelse() issued during 534 * cluster building clears B_RELBUF (see bqrelse() 535 * comment). If direct I/O was specified, we have 536 * to restore it here to allow the buffer and VM 537 * to be freed. 538 */ 539 if (tbp->b_flags & B_DIRECT) 540 tbp->b_flags |= B_RELBUF; 541 } 542 biodone(&tbp->b_bio1); 543 } 544 relpbuf(bp, &cluster_pbuf_freecnt); 545 } 546 547 /* 548 * cluster_wbuild_wb: 549 * 550 * Implement modified write build for cluster. 551 * 552 * write_behind = 0 write behind disabled 553 * write_behind = 1 write behind normal (default) 554 * write_behind = 2 write behind backed-off 555 */ 556 557 static __inline int 558 cluster_wbuild_wb(struct vnode *vp, int size, off_t start_loffset, int len) 559 { 560 int r = 0; 561 562 switch(write_behind) { 563 case 2: 564 if (start_loffset < len) 565 break; 566 start_loffset -= len; 567 /* fall through */ 568 case 1: 569 r = cluster_wbuild(vp, size, start_loffset, len); 570 /* fall through */ 571 default: 572 /* fall through */ 573 break; 574 } 575 return(r); 576 } 577 578 /* 579 * Do clustered write for FFS. 580 * 581 * Three cases: 582 * 1. Write is not sequential (write asynchronously) 583 * Write is sequential: 584 * 2. beginning of cluster - begin cluster 585 * 3. middle of a cluster - add to cluster 586 * 4. end of a cluster - asynchronously write cluster 587 */ 588 void 589 cluster_write(struct buf *bp, off_t filesize, int seqcount) 590 { 591 struct vnode *vp; 592 off_t loffset; 593 int maxclen, cursize; 594 int lblocksize; 595 int async; 596 597 vp = bp->b_vp; 598 if (vp->v_type == VREG) { 599 async = vp->v_mount->mnt_flag & MNT_ASYNC; 600 lblocksize = vp->v_mount->mnt_stat.f_iosize; 601 } else { 602 async = 0; 603 lblocksize = bp->b_bufsize; 604 } 605 loffset = bp->b_loffset; 606 KASSERT(bp->b_loffset != NOOFFSET, 607 ("cluster_write: no buffer offset")); 608 609 /* Initialize vnode to beginning of file. */ 610 if (loffset == 0) 611 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 612 613 if (vp->v_clen == 0 || loffset != vp->v_lastw + lblocksize || 614 bp->b_bio2.bio_offset == NOOFFSET || 615 (bp->b_bio2.bio_offset != vp->v_lasta + lblocksize)) { 616 maxclen = vp->v_mount->mnt_iosize_max; 617 if (vp->v_clen != 0) { 618 /* 619 * Next block is not sequential. 620 * 621 * If we are not writing at end of file, the process 622 * seeked to another point in the file since its last 623 * write, or we have reached our maximum cluster size, 624 * then push the previous cluster. Otherwise try 625 * reallocating to make it sequential. 626 * 627 * Change to algorithm: only push previous cluster if 628 * it was sequential from the point of view of the 629 * seqcount heuristic, otherwise leave the buffer 630 * intact so we can potentially optimize the I/O 631 * later on in the buf_daemon or update daemon 632 * flush. 633 */ 634 cursize = vp->v_lastw - vp->v_cstart + lblocksize; 635 if (bp->b_loffset + lblocksize != filesize || 636 loffset != vp->v_lastw + lblocksize || vp->v_clen <= cursize) { 637 if (!async && seqcount > 0) { 638 cluster_wbuild_wb(vp, lblocksize, 639 vp->v_cstart, cursize); 640 } 641 } else { 642 struct buf **bpp, **endbp; 643 struct cluster_save *buflist; 644 645 buflist = cluster_collectbufs(vp, bp, 646 lblocksize); 647 endbp = &buflist->bs_children 648 [buflist->bs_nchildren - 1]; 649 if (VOP_REALLOCBLKS(vp, buflist)) { 650 /* 651 * Failed, push the previous cluster 652 * if *really* writing sequentially 653 * in the logical file (seqcount > 1), 654 * otherwise delay it in the hopes that 655 * the low level disk driver can 656 * optimize the write ordering. 657 */ 658 for (bpp = buflist->bs_children; 659 bpp < endbp; bpp++) 660 brelse(*bpp); 661 kfree(buflist, M_SEGMENT); 662 if (seqcount > 1) { 663 cluster_wbuild_wb(vp, 664 lblocksize, vp->v_cstart, 665 cursize); 666 } 667 } else { 668 /* 669 * Succeeded, keep building cluster. 670 */ 671 for (bpp = buflist->bs_children; 672 bpp <= endbp; bpp++) 673 bdwrite(*bpp); 674 kfree(buflist, M_SEGMENT); 675 vp->v_lastw = loffset; 676 vp->v_lasta = bp->b_bio2.bio_offset; 677 return; 678 } 679 } 680 } 681 /* 682 * Consider beginning a cluster. If at end of file, make 683 * cluster as large as possible, otherwise find size of 684 * existing cluster. 685 */ 686 if ((vp->v_type == VREG) && 687 bp->b_loffset + lblocksize != filesize && 688 (bp->b_bio2.bio_offset == NOOFFSET) && 689 (VOP_BMAP(vp, loffset, &bp->b_bio2.bio_offset, &maxclen, NULL) || 690 bp->b_bio2.bio_offset == NOOFFSET)) { 691 bawrite(bp); 692 vp->v_clen = 0; 693 vp->v_lasta = bp->b_bio2.bio_offset; 694 vp->v_cstart = loffset + lblocksize; 695 vp->v_lastw = loffset; 696 return; 697 } 698 if (maxclen > lblocksize) 699 vp->v_clen = maxclen - lblocksize; 700 else 701 vp->v_clen = 0; 702 if (!async && vp->v_clen == 0) { /* I/O not contiguous */ 703 vp->v_cstart = loffset + lblocksize; 704 bawrite(bp); 705 } else { /* Wait for rest of cluster */ 706 vp->v_cstart = loffset; 707 bdwrite(bp); 708 } 709 } else if (loffset == vp->v_cstart + vp->v_clen) { 710 /* 711 * At end of cluster, write it out if seqcount tells us we 712 * are operating sequentially, otherwise let the buf or 713 * update daemon handle it. 714 */ 715 bdwrite(bp); 716 if (seqcount > 1) 717 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, 718 vp->v_clen + lblocksize); 719 vp->v_clen = 0; 720 vp->v_cstart = loffset + lblocksize; 721 } else if (vm_page_count_severe()) { 722 /* 723 * We are low on memory, get it going NOW 724 */ 725 bawrite(bp); 726 } else { 727 /* 728 * In the middle of a cluster, so just delay the I/O for now. 729 */ 730 bdwrite(bp); 731 } 732 vp->v_lastw = loffset; 733 vp->v_lasta = bp->b_bio2.bio_offset; 734 } 735 736 737 /* 738 * This is an awful lot like cluster_rbuild...wish they could be combined. 739 * The last lbn argument is the current block on which I/O is being 740 * performed. Check to see that it doesn't fall in the middle of 741 * the current block (if last_bp == NULL). 742 */ 743 int 744 cluster_wbuild(struct vnode *vp, int size, off_t start_loffset, int bytes) 745 { 746 struct buf *bp, *tbp; 747 int i, j; 748 int totalwritten = 0; 749 750 while (bytes > 0) { 751 crit_enter(); 752 /* 753 * If the buffer is not delayed-write (i.e. dirty), or it 754 * is delayed-write but either locked or inval, it cannot 755 * partake in the clustered write. 756 */ 757 if (((tbp = findblk(vp, start_loffset)) == NULL) || 758 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 759 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) || 760 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 761 start_loffset += size; 762 bytes -= size; 763 crit_exit(); 764 continue; 765 } 766 bremfree(tbp); 767 KKASSERT(tbp->b_cmd == BUF_CMD_DONE); 768 crit_exit(); 769 770 /* 771 * Extra memory in the buffer, punt on this buffer. 772 * XXX we could handle this in most cases, but we would 773 * have to push the extra memory down to after our max 774 * possible cluster size and then potentially pull it back 775 * up if the cluster was terminated prematurely--too much 776 * hassle. 777 */ 778 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 779 (tbp->b_bcount != tbp->b_bufsize) || 780 (tbp->b_bcount != size) || 781 (bytes == size) || 782 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 783 totalwritten += tbp->b_bufsize; 784 bawrite(tbp); 785 start_loffset += size; 786 bytes -= size; 787 continue; 788 } 789 790 /* 791 * Set up the pbuf. Track our append point with b_bcount 792 * and b_bufsize. b_bufsize is not used by the device but 793 * our caller uses it to loop clusters and we use it to 794 * detect a premature EOF on the block device. 795 */ 796 bp->b_bcount = 0; 797 bp->b_bufsize = 0; 798 bp->b_xio.xio_npages = 0; 799 bp->b_loffset = tbp->b_loffset; 800 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset; 801 802 /* 803 * We are synthesizing a buffer out of vm_page_t's, but 804 * if the block size is not page aligned then the starting 805 * address may not be either. Inherit the b_data offset 806 * from the original buffer. 807 */ 808 bp->b_data = (char *)((vm_offset_t)bp->b_data | 809 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 810 bp->b_flags &= ~B_ERROR; 811 bp->b_flags |= B_CLUSTER | B_BNOCLIP | 812 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 813 bp->b_bio1.bio_done = cluster_callback; 814 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 815 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 816 /* 817 * From this location in the file, scan forward to see 818 * if there are buffers with adjacent data that need to 819 * be written as well. 820 */ 821 for (i = 0; i < bytes; (i += size), (start_loffset += size)) { 822 if (i != 0) { /* If not the first buffer */ 823 crit_enter(); 824 /* 825 * If the adjacent data is not even in core it 826 * can't need to be written. 827 */ 828 if ((tbp = findblk(vp, start_loffset)) == NULL) { 829 crit_exit(); 830 break; 831 } 832 833 /* 834 * If it IS in core, but has different 835 * characteristics, or is locked (which 836 * means it could be undergoing a background 837 * I/O or be in a weird state), then don't 838 * cluster with it. 839 */ 840 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 841 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 842 != (B_DELWRI | B_CLUSTEROK | 843 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 844 (tbp->b_flags & B_LOCKED) || 845 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) || 846 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 847 crit_exit(); 848 break; 849 } 850 851 /* 852 * Check that the combined cluster 853 * would make sense with regard to pages 854 * and would not be too large 855 */ 856 if ((tbp->b_bcount != size) || 857 ((bp->b_bio2.bio_offset + i) != 858 tbp->b_bio2.bio_offset) || 859 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) > 860 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 861 BUF_UNLOCK(tbp); 862 crit_exit(); 863 break; 864 } 865 /* 866 * Ok, it's passed all the tests, 867 * so remove it from the free list 868 * and mark it busy. We will use it. 869 */ 870 bremfree(tbp); 871 KKASSERT(tbp->b_cmd == BUF_CMD_DONE); 872 crit_exit(); 873 } /* end of code for non-first buffers only */ 874 875 /* 876 * If the IO is via the VM then we do some 877 * special VM hackery (yuck). Since the buffer's 878 * block size may not be page-aligned it is possible 879 * for a page to be shared between two buffers. We 880 * have to get rid of the duplication when building 881 * the cluster. 882 */ 883 if (tbp->b_flags & B_VMIO) { 884 vm_page_t m; 885 886 if (i != 0) { /* if not first buffer */ 887 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 888 m = tbp->b_xio.xio_pages[j]; 889 if (m->flags & PG_BUSY) { 890 bqrelse(tbp); 891 goto finishcluster; 892 } 893 } 894 } 895 896 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 897 m = tbp->b_xio.xio_pages[j]; 898 vm_page_io_start(m); 899 vm_object_pip_add(m->object, 1); 900 if ((bp->b_xio.xio_npages == 0) || 901 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) { 902 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 903 bp->b_xio.xio_npages++; 904 } 905 } 906 } 907 bp->b_bcount += size; 908 bp->b_bufsize += size; 909 910 crit_enter(); 911 bundirty(tbp); 912 tbp->b_flags &= ~B_ERROR; 913 tbp->b_flags |= B_ASYNC; 914 tbp->b_cmd = BUF_CMD_WRITE; 915 crit_exit(); 916 BUF_KERNPROC(tbp); 917 cluster_append(&bp->b_bio1, tbp); 918 919 /* 920 * check for latent dependencies to be handled 921 */ 922 if (LIST_FIRST(&tbp->b_dep) != NULL) 923 buf_start(tbp); 924 } 925 finishcluster: 926 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 927 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages); 928 if (bp->b_bufsize > bp->b_kvasize) { 929 panic( 930 "cluster_wbuild: b_bufsize(%d) > b_kvasize(%d)\n", 931 bp->b_bufsize, bp->b_kvasize); 932 } 933 totalwritten += bp->b_bufsize; 934 bp->b_dirtyoff = 0; 935 bp->b_dirtyend = bp->b_bufsize; 936 bp->b_flags |= B_ASYNC; 937 bp->b_cmd = BUF_CMD_WRITE; 938 vfs_busy_pages(vp, bp); 939 bp->b_runningbufspace = bp->b_bufsize; 940 runningbufspace += bp->b_runningbufspace; 941 BUF_KERNPROC(bp); /* B_ASYNC */ 942 vn_strategy(vp, &bp->b_bio1); 943 944 bytes -= i; 945 } 946 return totalwritten; 947 } 948 949 /* 950 * Collect together all the buffers in a cluster. 951 * Plus add one additional buffer. 952 */ 953 static struct cluster_save * 954 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int lblocksize) 955 { 956 struct cluster_save *buflist; 957 struct buf *bp; 958 off_t loffset; 959 int i, len; 960 961 len = (int)(vp->v_lastw - vp->v_cstart + lblocksize) / lblocksize; 962 buflist = kmalloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 963 M_SEGMENT, M_WAITOK); 964 buflist->bs_nchildren = 0; 965 buflist->bs_children = (struct buf **) (buflist + 1); 966 for (loffset = vp->v_cstart, i = 0; i < len; (loffset += lblocksize), i++) { 967 (void) bread(vp, loffset, last_bp->b_bcount, &bp); 968 buflist->bs_children[i] = bp; 969 if (bp->b_bio2.bio_offset == NOOFFSET) { 970 VOP_BMAP(bp->b_vp, bp->b_loffset, 971 &bp->b_bio2.bio_offset, NULL, NULL); 972 } 973 } 974 buflist->bs_children[i] = bp = last_bp; 975 if (bp->b_bio2.bio_offset == NOOFFSET) { 976 VOP_BMAP(bp->b_vp, bp->b_loffset, 977 &bp->b_bio2.bio_offset, NULL, NULL); 978 } 979 buflist->bs_nchildren = i + 1; 980 return (buflist); 981 } 982 983 void 984 cluster_append(struct bio *bio, struct buf *tbp) 985 { 986 tbp->b_cluster_next = NULL; 987 if (bio->bio_caller_info1.cluster_head == NULL) { 988 bio->bio_caller_info1.cluster_head = tbp; 989 bio->bio_caller_info2.cluster_tail = tbp; 990 } else { 991 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp; 992 bio->bio_caller_info2.cluster_tail = tbp; 993 } 994 } 995 996