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 1.18 2006/03/10 17:51:54 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 static struct buf * 70 cluster_rbuild (struct vnode *vp, u_quad_t filesize, daddr_t lbn, 71 daddr_t blkno, long size, int run, struct buf *fbp); 72 static void cluster_callback (struct bio *); 73 74 75 static int write_behind = 1; 76 SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, ""); 77 78 extern vm_page_t bogus_page; 79 80 extern int cluster_pbuf_freecnt; 81 82 /* 83 * Maximum number of blocks for read-ahead. 84 */ 85 #define MAXRA 32 86 87 /* 88 * This replaces bread. 89 */ 90 int 91 cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, 92 long size, long totread, int seqcount, struct buf **bpp) 93 { 94 struct buf *bp, *rbp, *reqbp; 95 daddr_t blkno, origblkno; 96 int error, num_ra; 97 int i; 98 int maxra, racluster; 99 long origtotread; 100 101 error = 0; 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 = 2 * racluster + (totread / size); 109 if (maxra > MAXRA) 110 maxra = MAXRA; 111 if (maxra > nbuf/8) 112 maxra = nbuf/8; 113 114 /* 115 * get the requested block 116 */ 117 *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0); 118 origblkno = lblkno; 119 origtotread = totread; 120 121 /* 122 * if it is in the cache, then check to see if the reads have been 123 * sequential. If they have, then try some read-ahead, otherwise 124 * back-off on prospective read-aheads. 125 */ 126 if (bp->b_flags & B_CACHE) { 127 if (!seqcount) { 128 return 0; 129 } else if ((bp->b_flags & B_RAM) == 0) { 130 return 0; 131 } else { 132 struct buf *tbp; 133 bp->b_flags &= ~B_RAM; 134 /* 135 * We do the crit here so that there is no window 136 * between the findblk and the b_usecount increment 137 * below. We opt to keep the crit out of the loop 138 * for efficiency. 139 */ 140 crit_enter(); 141 for (i = 1; i < maxra; i++) { 142 143 if (!(tbp = findblk(vp, lblkno+i))) { 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 lblkno += i; 160 } 161 reqbp = bp = NULL; 162 } else { 163 off_t firstread = bp->b_loffset; 164 165 KASSERT(firstread != NOOFFSET, 166 ("cluster_read: no buffer offset")); 167 if (firstread + totread > filesize) 168 totread = filesize - firstread; 169 if (totread > size) { 170 int nblks = 0; 171 int ncontigafter; 172 while (totread > 0) { 173 nblks++; 174 totread -= size; 175 } 176 if (nblks == 1) 177 goto single_block_read; 178 if (nblks > racluster) 179 nblks = racluster; 180 181 error = VOP_BMAP(vp, lblkno, NULL, 182 &blkno, &ncontigafter, NULL); 183 if (error) 184 goto single_block_read; 185 if (blkno == -1) 186 goto single_block_read; 187 if (ncontigafter == 0) 188 goto single_block_read; 189 if (ncontigafter + 1 < nblks) 190 nblks = ncontigafter + 1; 191 192 bp = cluster_rbuild(vp, filesize, lblkno, 193 blkno, size, nblks, bp); 194 lblkno += (bp->b_bufsize / size); 195 } else { 196 single_block_read: 197 /* 198 * if it isn't in the cache, then get a chunk from 199 * disk if sequential, otherwise just get the block. 200 */ 201 bp->b_flags |= B_READ | B_RAM; 202 lblkno += 1; 203 } 204 } 205 206 /* 207 * If we have been doing sequential I/O, then do some read-ahead. 208 */ 209 rbp = NULL; 210 if (seqcount && 211 lblkno < origblkno + seqcount && 212 (u_quad_t)(lblkno + 1) * size <= filesize 213 ) { 214 rbp = getblk(vp, lblkno, size, 0, 0); 215 if ((rbp->b_flags & B_CACHE) == 0) { 216 int nblksread; 217 int ntoread; 218 219 error = VOP_BMAP(vp, lblkno, NULL, 220 &blkno, &num_ra, NULL); 221 if (error || blkno == (daddr_t)-1) { 222 rbp->b_flags &= ~(B_ASYNC | B_READ); 223 brelse(rbp); 224 rbp = NULL; 225 goto no_read_ahead; 226 } 227 ntoread = num_ra + 1; 228 nblksread = (origtotread + size - 1) / size; 229 if (seqcount < nblksread) 230 seqcount = nblksread; 231 if (seqcount < ntoread) 232 ntoread = seqcount; 233 234 rbp->b_flags |= B_READ | B_ASYNC | B_RAM; 235 if (num_ra) { 236 rbp = cluster_rbuild(vp, filesize, lblkno, 237 blkno, size, ntoread, rbp); 238 } else { 239 rbp->b_bio2.bio_blkno = blkno; 240 } 241 } 242 } 243 no_read_ahead: 244 245 /* 246 * Handle the synchronous read 247 */ 248 if (bp) { 249 #if defined(CLUSTERDEBUG) 250 if (rcluster) 251 printf("S(%ld,%ld,%d) ", 252 (long)bp->b_lblkno, bp->b_bcount, seqcount); 253 #endif 254 if ((bp->b_flags & B_CLUSTER) == 0) { 255 vfs_busy_pages(bp, 0); 256 } 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 rbp->b_flags &= ~(B_ASYNC | B_READ); 270 brelse(rbp); 271 } else if (rbp->b_flags & B_CACHE) { 272 rbp->b_flags &= ~(B_ASYNC | B_READ); 273 bqrelse(rbp); 274 } else { 275 #if defined(CLUSTERDEBUG) 276 if (rcluster) { 277 if (bp) 278 printf("A+(%ld,%ld,%ld,%d) ", 279 (long)rbp->b_lblkno, rbp->b_bcount, 280 (long)(rbp->b_lblkno - origblkno), 281 seqcount); 282 else 283 printf("A(%ld,%ld,%ld,%d) ", 284 (long)rbp->b_lblkno, rbp->b_bcount, 285 (long)(rbp->b_lblkno - origblkno), 286 seqcount); 287 } 288 #endif 289 290 if ((rbp->b_flags & B_CLUSTER) == 0) { 291 vfs_busy_pages(rbp, 0); 292 } 293 rbp->b_flags &= ~(B_ERROR|B_INVAL); 294 if ((rbp->b_flags & B_ASYNC) || rbp->b_bio1.bio_done != NULL) 295 BUF_KERNPROC(rbp); 296 vn_strategy(vp, &rbp->b_bio1); 297 } 298 } 299 if (reqbp) 300 return (biowait(reqbp)); 301 else 302 return (error); 303 } 304 305 /* 306 * If blocks are contiguous on disk, use this to provide clustered 307 * read ahead. We will read as many blocks as possible sequentially 308 * and then parcel them up into logical blocks in the buffer hash table. 309 */ 310 static struct buf * 311 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 312 daddr_t blkno, long size, int run, struct buf *fbp) 313 { 314 struct buf *bp, *tbp; 315 daddr_t bn; 316 int i, inc, j; 317 318 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 319 ("cluster_rbuild: size %ld != filesize %ld\n", 320 size, vp->v_mount->mnt_stat.f_iosize)); 321 322 /* 323 * avoid a division 324 */ 325 while ((u_quad_t) size * (lbn + run) > filesize) { 326 --run; 327 } 328 329 tbp = fbp; 330 tbp->b_flags |= B_READ; 331 tbp->b_bio2.bio_blkno = blkno; 332 if( (tbp->b_flags & B_MALLOC) || 333 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) 334 return tbp; 335 336 bp = trypbuf(&cluster_pbuf_freecnt); 337 if (bp == 0) 338 return tbp; 339 340 /* 341 * We are synthesizing a buffer out of vm_page_t's, but 342 * if the block size is not page aligned then the starting 343 * address may not be either. Inherit the b_data offset 344 * from the original buffer. 345 */ 346 bp->b_data = (char *)((vm_offset_t)bp->b_data | 347 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 348 bp->b_flags = B_ASYNC | B_READ | B_CLUSTER | B_VMIO; 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_lblkno = lbn; 353 bp->b_loffset = tbp->b_loffset; 354 bp->b_bio2.bio_blkno = (daddr_t)-1; 355 KASSERT(bp->b_loffset != NOOFFSET, 356 ("cluster_rbuild: no buffer offset")); 357 pbgetvp(vp, bp); 358 359 bp->b_bcount = 0; 360 bp->b_bufsize = 0; 361 bp->b_xio.xio_npages = 0; 362 363 inc = btodb(size); 364 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 365 if (i != 0) { 366 if ((bp->b_xio.xio_npages * PAGE_SIZE) + 367 round_page(size) > vp->v_mount->mnt_iosize_max) { 368 break; 369 } 370 371 /* 372 * Shortcut some checks and try to avoid buffers that 373 * would block in the lock. The same checks have to 374 * be made again after we officially get the buffer. 375 */ 376 if ((tbp = findblk(vp, lbn + i)) != NULL) { 377 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) 378 break; 379 BUF_UNLOCK(tbp); 380 381 for (j = 0; j < tbp->b_xio.xio_npages; j++) { 382 if (tbp->b_xio.xio_pages[j]->valid) 383 break; 384 } 385 386 if (j != tbp->b_xio.xio_npages) 387 break; 388 389 if (tbp->b_bcount != size) 390 break; 391 } 392 393 tbp = getblk(vp, lbn + i, size, 0, 0); 394 395 /* 396 * Stop scanning if the buffer is fuly valid 397 * (marked B_CACHE), or locked (may be doing a 398 * background write), or if the buffer is not 399 * VMIO backed. The clustering code can only deal 400 * with VMIO-backed buffers. 401 */ 402 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || 403 (tbp->b_flags & B_VMIO) == 0) { 404 bqrelse(tbp); 405 break; 406 } 407 408 /* 409 * The buffer must be completely invalid in order to 410 * take part in the cluster. If it is partially valid 411 * then we stop. 412 */ 413 for (j = 0;j < tbp->b_xio.xio_npages; j++) { 414 if (tbp->b_xio.xio_pages[j]->valid) 415 break; 416 } 417 if (j != tbp->b_xio.xio_npages) { 418 bqrelse(tbp); 419 break; 420 } 421 422 /* 423 * Set a read-ahead mark as appropriate 424 */ 425 if (i == 1 || i == (run - 1)) 426 tbp->b_flags |= B_RAM; 427 428 /* 429 * Set the buffer up for an async read (XXX should 430 * we do this only if we do not wind up brelse()ing?). 431 * Set the block number if it isn't set, otherwise 432 * if it is make sure it matches the block number we 433 * expect. 434 */ 435 tbp->b_flags |= B_READ | B_ASYNC; 436 if (tbp->b_bio2.bio_blkno == (daddr_t)-1) { 437 tbp->b_bio2.bio_blkno = bn; 438 } else if (tbp->b_bio2.bio_blkno != bn) { 439 brelse(tbp); 440 break; 441 } 442 } 443 /* 444 * XXX fbp from caller may not be B_ASYNC, but we are going 445 * to biodone() it in cluster_callback() anyway 446 */ 447 BUF_KERNPROC(tbp); 448 cluster_append(&bp->b_bio1, tbp); 449 for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { 450 vm_page_t m; 451 m = tbp->b_xio.xio_pages[j]; 452 vm_page_io_start(m); 453 vm_object_pip_add(m->object, 1); 454 if ((bp->b_xio.xio_npages == 0) || 455 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) { 456 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 457 bp->b_xio.xio_npages++; 458 } 459 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 460 tbp->b_xio.xio_pages[j] = bogus_page; 461 } 462 /* 463 * XXX shouldn't this be += size for both, like in 464 * cluster_wbuild()? 465 * 466 * Don't inherit tbp->b_bufsize as it may be larger due to 467 * a non-page-aligned size. Instead just aggregate using 468 * 'size'. 469 */ 470 if (tbp->b_bcount != size) 471 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 472 if (tbp->b_bufsize != size) 473 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 474 bp->b_bcount += size; 475 bp->b_bufsize += size; 476 } 477 478 /* 479 * Fully valid pages in the cluster are already good and do not need 480 * to be re-read from disk. Replace the page with bogus_page 481 */ 482 for (j = 0; j < bp->b_xio.xio_npages; j++) { 483 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) == 484 VM_PAGE_BITS_ALL) { 485 bp->b_xio.xio_pages[j] = bogus_page; 486 } 487 } 488 if (bp->b_bufsize > bp->b_kvasize) 489 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)", 490 bp->b_bufsize, bp->b_kvasize); 491 bp->b_kvasize = bp->b_bufsize; 492 493 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 494 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages); 495 return (bp); 496 } 497 498 /* 499 * Cleanup after a clustered read or write. 500 * This is complicated by the fact that any of the buffers might have 501 * extra memory (if there were no empty buffer headers at allocbuf time) 502 * that we will need to shift around. 503 * 504 * The returned bio is &bp->b_bio1 505 */ 506 void 507 cluster_callback(struct bio *bio) 508 { 509 struct buf *bp = bio->bio_buf; 510 struct buf *tbp; 511 int error = 0; 512 513 /* 514 * Must propogate errors to all the components. 515 */ 516 if (bp->b_flags & B_ERROR) 517 error = bp->b_error; 518 519 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages); 520 /* 521 * Move memory from the large cluster buffer into the component 522 * buffers and mark IO as done on these. Since the memory map 523 * is the same, no actual copying is required. 524 */ 525 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) { 526 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next; 527 if (error) { 528 tbp->b_flags |= B_ERROR; 529 tbp->b_error = error; 530 } else { 531 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 532 tbp->b_flags &= ~(B_ERROR|B_INVAL); 533 /* 534 * XXX the bdwrite()/bqrelse() issued during 535 * cluster building clears B_RELBUF (see bqrelse() 536 * comment). If direct I/O was specified, we have 537 * to restore it here to allow the buffer and VM 538 * to be freed. 539 */ 540 if (tbp->b_flags & B_DIRECT) 541 tbp->b_flags |= B_RELBUF; 542 } 543 biodone(&tbp->b_bio1); 544 } 545 relpbuf(bp, &cluster_pbuf_freecnt); 546 } 547 548 /* 549 * cluster_wbuild_wb: 550 * 551 * Implement modified write build for cluster. 552 * 553 * write_behind = 0 write behind disabled 554 * write_behind = 1 write behind normal (default) 555 * write_behind = 2 write behind backed-off 556 */ 557 558 static __inline int 559 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 560 { 561 int r = 0; 562 563 switch(write_behind) { 564 case 2: 565 if (start_lbn < len) 566 break; 567 start_lbn -= len; 568 /* fall through */ 569 case 1: 570 r = cluster_wbuild(vp, size, start_lbn, len); 571 /* fall through */ 572 default: 573 /* fall through */ 574 break; 575 } 576 return(r); 577 } 578 579 /* 580 * Do clustered write for FFS. 581 * 582 * Three cases: 583 * 1. Write is not sequential (write asynchronously) 584 * Write is sequential: 585 * 2. beginning of cluster - begin cluster 586 * 3. middle of a cluster - add to cluster 587 * 4. end of a cluster - asynchronously write cluster 588 */ 589 void 590 cluster_write(struct buf *bp, u_quad_t filesize, int seqcount) 591 { 592 struct vnode *vp; 593 daddr_t lbn; 594 int maxclen, cursize; 595 int lblocksize; 596 int async; 597 598 vp = bp->b_vp; 599 if (vp->v_type == VREG) { 600 async = vp->v_mount->mnt_flag & MNT_ASYNC; 601 lblocksize = vp->v_mount->mnt_stat.f_iosize; 602 } else { 603 async = 0; 604 lblocksize = bp->b_bufsize; 605 } 606 lbn = bp->b_lblkno; 607 KASSERT(bp->b_loffset != NOOFFSET, 608 ("cluster_write: no buffer offset")); 609 610 /* Initialize vnode to beginning of file. */ 611 if (lbn == 0) 612 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 613 614 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 615 bp->b_bio2.bio_blkno == (daddr_t)-1 || 616 (bp->b_bio2.bio_blkno != vp->v_lasta + btodb(lblocksize))) { 617 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 618 if (vp->v_clen != 0) { 619 /* 620 * Next block is not sequential. 621 * 622 * If we are not writing at end of file, the process 623 * seeked to another point in the file since its last 624 * write, or we have reached our maximum cluster size, 625 * then push the previous cluster. Otherwise try 626 * reallocating to make it sequential. 627 * 628 * Change to algorithm: only push previous cluster if 629 * it was sequential from the point of view of the 630 * seqcount heuristic, otherwise leave the buffer 631 * intact so we can potentially optimize the I/O 632 * later on in the buf_daemon or update daemon 633 * flush. 634 */ 635 cursize = vp->v_lastw - vp->v_cstart + 1; 636 if (((u_quad_t) bp->b_loffset + lblocksize) != filesize || 637 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 638 if (!async && seqcount > 0) { 639 cluster_wbuild_wb(vp, lblocksize, 640 vp->v_cstart, cursize); 641 } 642 } else { 643 struct buf **bpp, **endbp; 644 struct cluster_save *buflist; 645 646 buflist = cluster_collectbufs(vp, bp); 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 free(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 free(buflist, M_SEGMENT); 675 vp->v_lastw = lbn; 676 vp->v_lasta = bp->b_bio2.bio_blkno; 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 ((u_quad_t) bp->b_loffset + lblocksize) != filesize && 688 (bp->b_bio2.bio_blkno == (daddr_t)-1) && 689 (VOP_BMAP(vp, lbn, NULL, &bp->b_bio2.bio_blkno, &maxclen, NULL) || 690 bp->b_bio2.bio_blkno == (daddr_t)-1)) { 691 bawrite(bp); 692 vp->v_clen = 0; 693 vp->v_lasta = bp->b_bio2.bio_blkno; 694 vp->v_cstart = lbn + 1; 695 vp->v_lastw = lbn; 696 return; 697 } 698 vp->v_clen = maxclen; 699 if (!async && maxclen == 0) { /* I/O not contiguous */ 700 vp->v_cstart = lbn + 1; 701 bawrite(bp); 702 } else { /* Wait for rest of cluster */ 703 vp->v_cstart = lbn; 704 bdwrite(bp); 705 } 706 } else if (lbn == vp->v_cstart + vp->v_clen) { 707 /* 708 * At end of cluster, write it out if seqcount tells us we 709 * are operating sequentially, otherwise let the buf or 710 * update daemon handle it. 711 */ 712 bdwrite(bp); 713 if (seqcount > 1) 714 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 715 vp->v_clen = 0; 716 vp->v_cstart = lbn + 1; 717 } else if (vm_page_count_severe()) { 718 /* 719 * We are low on memory, get it going NOW 720 */ 721 bawrite(bp); 722 } else { 723 /* 724 * In the middle of a cluster, so just delay the I/O for now. 725 */ 726 bdwrite(bp); 727 } 728 vp->v_lastw = lbn; 729 vp->v_lasta = bp->b_bio2.bio_blkno; 730 } 731 732 733 /* 734 * This is an awful lot like cluster_rbuild...wish they could be combined. 735 * The last lbn argument is the current block on which I/O is being 736 * performed. Check to see that it doesn't fall in the middle of 737 * the current block (if last_bp == NULL). 738 */ 739 int 740 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len) 741 { 742 struct buf *bp, *tbp; 743 int i, j; 744 int totalwritten = 0; 745 int dbsize = btodb(size); 746 747 while (len > 0) { 748 crit_enter(); 749 /* 750 * If the buffer is not delayed-write (i.e. dirty), or it 751 * is delayed-write but either locked or inval, it cannot 752 * partake in the clustered write. 753 */ 754 if (((tbp = findblk(vp, start_lbn)) == NULL) || 755 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 756 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 757 ++start_lbn; 758 --len; 759 crit_exit(); 760 continue; 761 } 762 bremfree(tbp); 763 tbp->b_flags &= ~B_DONE; 764 crit_exit(); 765 766 /* 767 * Extra memory in the buffer, punt on this buffer. 768 * XXX we could handle this in most cases, but we would 769 * have to push the extra memory down to after our max 770 * possible cluster size and then potentially pull it back 771 * up if the cluster was terminated prematurely--too much 772 * hassle. 773 */ 774 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 775 (tbp->b_bcount != tbp->b_bufsize) || 776 (tbp->b_bcount != size) || 777 (len == 1) || 778 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 779 totalwritten += tbp->b_bufsize; 780 bawrite(tbp); 781 ++start_lbn; 782 --len; 783 continue; 784 } 785 786 /* 787 * We got a pbuf to make the cluster in. 788 * so initialise it. 789 */ 790 bp->b_bcount = 0; 791 bp->b_bufsize = 0; 792 bp->b_xio.xio_npages = 0; 793 bp->b_lblkno = tbp->b_lblkno; 794 bp->b_loffset = tbp->b_loffset; 795 bp->b_bio2.bio_blkno = tbp->b_bio2.bio_blkno; 796 797 /* 798 * We are synthesizing a buffer out of vm_page_t's, but 799 * if the block size is not page aligned then the starting 800 * address may not be either. Inherit the b_data offset 801 * from the original buffer. 802 */ 803 bp->b_data = (char *)((vm_offset_t)bp->b_data | 804 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 805 bp->b_flags |= B_CLUSTER | 806 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN)); 807 bp->b_bio1.bio_done = cluster_callback; 808 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 809 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 810 pbgetvp(vp, bp); 811 /* 812 * From this location in the file, scan forward to see 813 * if there are buffers with adjacent data that need to 814 * be written as well. 815 */ 816 for (i = 0; i < len; ++i, ++start_lbn) { 817 if (i != 0) { /* If not the first buffer */ 818 crit_enter(); 819 /* 820 * If the adjacent data is not even in core it 821 * can't need to be written. 822 */ 823 if ((tbp = findblk(vp, start_lbn)) == NULL) { 824 crit_exit(); 825 break; 826 } 827 828 /* 829 * If it IS in core, but has different 830 * characteristics, or is locked (which 831 * means it could be undergoing a background 832 * I/O or be in a weird state), then don't 833 * cluster with it. 834 */ 835 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 836 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 837 != (B_DELWRI | B_CLUSTEROK | 838 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 839 (tbp->b_flags & B_LOCKED) || 840 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 841 crit_exit(); 842 break; 843 } 844 845 /* 846 * Check that the combined cluster 847 * would make sense with regard to pages 848 * and would not be too large 849 */ 850 if ((tbp->b_bcount != size) || 851 ((bp->b_bio2.bio_blkno + (dbsize * i)) != 852 tbp->b_bio2.bio_blkno) || 853 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) > 854 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 855 BUF_UNLOCK(tbp); 856 crit_exit(); 857 break; 858 } 859 /* 860 * Ok, it's passed all the tests, 861 * so remove it from the free list 862 * and mark it busy. We will use it. 863 */ 864 bremfree(tbp); 865 tbp->b_flags &= ~B_DONE; 866 crit_exit(); 867 } /* end of code for non-first buffers only */ 868 869 /* 870 * If the IO is via the VM then we do some 871 * special VM hackery (yuck). Since the buffer's 872 * block size may not be page-aligned it is possible 873 * for a page to be shared between two buffers. We 874 * have to get rid of the duplication when building 875 * the cluster. 876 */ 877 if (tbp->b_flags & B_VMIO) { 878 vm_page_t m; 879 880 if (i != 0) { /* if not first buffer */ 881 for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { 882 m = tbp->b_xio.xio_pages[j]; 883 if (m->flags & PG_BUSY) { 884 bqrelse(tbp); 885 goto finishcluster; 886 } 887 } 888 } 889 890 for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { 891 m = tbp->b_xio.xio_pages[j]; 892 vm_page_io_start(m); 893 vm_object_pip_add(m->object, 1); 894 if ((bp->b_xio.xio_npages == 0) || 895 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) { 896 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 897 bp->b_xio.xio_npages++; 898 } 899 } 900 } 901 bp->b_bcount += size; 902 bp->b_bufsize += size; 903 904 crit_enter(); 905 bundirty(tbp); 906 tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR); 907 tbp->b_flags |= B_ASYNC; 908 crit_exit(); 909 BUF_KERNPROC(tbp); 910 cluster_append(&bp->b_bio1, tbp); 911 912 /* 913 * check for latent dependencies to be handled 914 */ 915 if (LIST_FIRST(&tbp->b_dep) != NULL && bioops.io_start) 916 (*bioops.io_start)(tbp); 917 918 } 919 finishcluster: 920 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 921 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages); 922 if (bp->b_bufsize > bp->b_kvasize) 923 panic( 924 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 925 bp->b_bufsize, bp->b_kvasize); 926 bp->b_kvasize = bp->b_bufsize; 927 totalwritten += bp->b_bufsize; 928 bp->b_dirtyoff = 0; 929 bp->b_dirtyend = bp->b_bufsize; 930 bawrite(bp); 931 932 len -= i; 933 } 934 return totalwritten; 935 } 936 937 /* 938 * Collect together all the buffers in a cluster. 939 * Plus add one additional buffer. 940 */ 941 static struct cluster_save * 942 cluster_collectbufs(struct vnode *vp, struct buf *last_bp) 943 { 944 struct cluster_save *buflist; 945 struct buf *bp; 946 daddr_t lbn; 947 int i, len; 948 949 len = vp->v_lastw - vp->v_cstart + 1; 950 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 951 M_SEGMENT, M_WAITOK); 952 buflist->bs_nchildren = 0; 953 buflist->bs_children = (struct buf **) (buflist + 1); 954 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 955 (void) bread(vp, lbn, last_bp->b_bcount, &bp); 956 buflist->bs_children[i] = bp; 957 if (bp->b_bio2.bio_blkno == (daddr_t)-1) 958 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_bio2.bio_blkno, 959 NULL, NULL); 960 } 961 buflist->bs_children[i] = bp = last_bp; 962 if (bp->b_bio2.bio_blkno == (daddr_t)-1) 963 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_bio2.bio_blkno, 964 NULL, NULL); 965 buflist->bs_nchildren = i + 1; 966 return (buflist); 967 } 968 969 void 970 cluster_append(struct bio *bio, struct buf *tbp) 971 { 972 tbp->b_cluster_next = NULL; 973 if (bio->bio_caller_info1.cluster_head == NULL) { 974 bio->bio_caller_info1.cluster_head = tbp; 975 bio->bio_caller_info2.cluster_tail = tbp; 976 } else { 977 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp; 978 bio->bio_caller_info2.cluster_tail = tbp; 979 } 980 } 981 982