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 1.15 2006/02/17 19:18:06 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 incore 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 = incore(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 && (lblkno < (origblkno + seqcount))) { 211 /* 212 * we now build the read-ahead buffer if it is desirable. 213 */ 214 if (((u_quad_t)(lblkno + 1) * size) <= filesize && 215 !(error = VOP_BMAP(vp, lblkno, NULL, &blkno, &num_ra, NULL)) && 216 blkno != -1) { 217 int nblksread; 218 int ntoread = num_ra + 1; 219 nblksread = (origtotread + size - 1) / size; 220 if (seqcount < nblksread) 221 seqcount = nblksread; 222 if (seqcount < ntoread) 223 ntoread = seqcount; 224 if (num_ra) { 225 rbp = cluster_rbuild(vp, filesize, lblkno, 226 blkno, size, ntoread, NULL); 227 } else { 228 rbp = getblk(vp, lblkno, size, 0, 0); 229 rbp->b_flags |= B_READ | B_ASYNC | B_RAM; 230 rbp->b_bio2.bio_blkno = blkno; 231 } 232 } 233 } 234 235 /* 236 * handle the synchronous read 237 */ 238 if (bp) { 239 #if defined(CLUSTERDEBUG) 240 if (rcluster) 241 printf("S(%ld,%ld,%d) ", 242 (long)bp->b_lblkno, bp->b_bcount, seqcount); 243 #endif 244 if ((bp->b_flags & B_CLUSTER) == 0) { 245 vfs_busy_pages(bp, 0); 246 } 247 bp->b_flags &= ~(B_ERROR|B_INVAL); 248 if ((bp->b_flags & B_ASYNC) || bp->b_bio1.bio_done != NULL) 249 BUF_KERNPROC(bp); 250 vn_strategy(vp, &bp->b_bio1); 251 error = bp->b_error; 252 } 253 254 /* 255 * and if we have read-aheads, do them too 256 */ 257 if (rbp) { 258 if (error) { 259 rbp->b_flags &= ~(B_ASYNC | B_READ); 260 brelse(rbp); 261 } else if (rbp->b_flags & B_CACHE) { 262 rbp->b_flags &= ~(B_ASYNC | B_READ); 263 bqrelse(rbp); 264 } else { 265 #if defined(CLUSTERDEBUG) 266 if (rcluster) { 267 if (bp) 268 printf("A+(%ld,%ld,%ld,%d) ", 269 (long)rbp->b_lblkno, rbp->b_bcount, 270 (long)(rbp->b_lblkno - origblkno), 271 seqcount); 272 else 273 printf("A(%ld,%ld,%ld,%d) ", 274 (long)rbp->b_lblkno, rbp->b_bcount, 275 (long)(rbp->b_lblkno - origblkno), 276 seqcount); 277 } 278 #endif 279 280 if ((rbp->b_flags & B_CLUSTER) == 0) { 281 vfs_busy_pages(rbp, 0); 282 } 283 rbp->b_flags &= ~(B_ERROR|B_INVAL); 284 if ((rbp->b_flags & B_ASYNC) || rbp->b_bio1.bio_done != NULL) 285 BUF_KERNPROC(rbp); 286 vn_strategy(vp, &rbp->b_bio1); 287 } 288 } 289 if (reqbp) 290 return (biowait(reqbp)); 291 else 292 return (error); 293 } 294 295 /* 296 * If blocks are contiguous on disk, use this to provide clustered 297 * read ahead. We will read as many blocks as possible sequentially 298 * and then parcel them up into logical blocks in the buffer hash table. 299 */ 300 static struct buf * 301 cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, 302 daddr_t blkno, long size, int run, struct buf *fbp) 303 { 304 struct buf *bp, *tbp; 305 daddr_t bn; 306 int i, inc, j; 307 308 KASSERT(size == vp->v_mount->mnt_stat.f_iosize, 309 ("cluster_rbuild: size %ld != filesize %ld\n", 310 size, 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_flags |= B_READ; 322 } else { 323 tbp = getblk(vp, lbn, size, 0, 0); 324 if (tbp->b_flags & B_CACHE) 325 return tbp; 326 tbp->b_flags |= B_ASYNC | B_READ | B_RAM; 327 } 328 329 tbp->b_bio2.bio_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_data = (char *)((vm_offset_t)bp->b_data | 345 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 346 bp->b_flags = B_ASYNC | B_READ | B_CLUSTER | B_VMIO; 347 bp->b_bio1.bio_done = cluster_callback; 348 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 349 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 350 bp->b_lblkno = lbn; 351 bp->b_loffset = tbp->b_loffset; 352 bp->b_bio2.bio_blkno = (daddr_t)-1; 353 KASSERT(bp->b_loffset != NOOFFSET, 354 ("cluster_rbuild: no buffer offset")); 355 pbgetvp(vp, bp); 356 357 bp->b_bcount = 0; 358 bp->b_bufsize = 0; 359 bp->b_xio.xio_npages = 0; 360 361 inc = btodb(size); 362 for (bn = blkno, i = 0; i < run; ++i, bn += inc) { 363 if (i != 0) { 364 if ((bp->b_xio.xio_npages * PAGE_SIZE) + 365 round_page(size) > vp->v_mount->mnt_iosize_max) { 366 break; 367 } 368 369 /* 370 * Shortcut some checks and try to avoid buffers that 371 * would block in the lock. The same checks have to 372 * be made again after we officially get the buffer. 373 */ 374 if ((tbp = incore(vp, lbn + i)) != NULL) { 375 if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) 376 break; 377 BUF_UNLOCK(tbp); 378 379 for (j = 0; j < tbp->b_xio.xio_npages; j++) { 380 if (tbp->b_xio.xio_pages[j]->valid) 381 break; 382 } 383 384 if (j != tbp->b_xio.xio_npages) 385 break; 386 387 if (tbp->b_bcount != size) 388 break; 389 } 390 391 tbp = getblk(vp, lbn + i, size, 0, 0); 392 393 /* 394 * Stop scanning if the buffer is fuly valid 395 * (marked B_CACHE), or locked (may be doing a 396 * background write), or if the buffer is not 397 * VMIO backed. The clustering code can only deal 398 * with VMIO-backed buffers. 399 */ 400 if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || 401 (tbp->b_flags & B_VMIO) == 0) { 402 bqrelse(tbp); 403 break; 404 } 405 406 /* 407 * The buffer must be completely invalid in order to 408 * take part in the cluster. If it is partially valid 409 * then we stop. 410 */ 411 for (j = 0;j < tbp->b_xio.xio_npages; j++) { 412 if (tbp->b_xio.xio_pages[j]->valid) 413 break; 414 } 415 if (j != tbp->b_xio.xio_npages) { 416 bqrelse(tbp); 417 break; 418 } 419 420 /* 421 * Set a read-ahead mark as appropriate 422 */ 423 if ((fbp && (i == 1)) || (i == (run - 1))) 424 tbp->b_flags |= B_RAM; 425 426 /* 427 * Set the buffer up for an async read (XXX should 428 * we do this only if we do not wind up brelse()ing?). 429 * Set the block number if it isn't set, otherwise 430 * if it is make sure it matches the block number we 431 * expect. 432 */ 433 tbp->b_flags |= B_READ | B_ASYNC; 434 if (tbp->b_bio2.bio_blkno == (daddr_t)-1) { 435 tbp->b_bio2.bio_blkno = bn; 436 } else if (tbp->b_bio2.bio_blkno != bn) { 437 brelse(tbp); 438 break; 439 } 440 } 441 /* 442 * XXX fbp from caller may not be B_ASYNC, but we are going 443 * to biodone() it in cluster_callback() anyway 444 */ 445 BUF_KERNPROC(tbp); 446 cluster_append(&bp->b_bio1, tbp); 447 for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { 448 vm_page_t m; 449 m = tbp->b_xio.xio_pages[j]; 450 vm_page_io_start(m); 451 vm_object_pip_add(m->object, 1); 452 if ((bp->b_xio.xio_npages == 0) || 453 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) { 454 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 455 bp->b_xio.xio_npages++; 456 } 457 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 458 tbp->b_xio.xio_pages[j] = bogus_page; 459 } 460 /* 461 * XXX shouldn't this be += size for both, like in 462 * cluster_wbuild()? 463 * 464 * Don't inherit tbp->b_bufsize as it may be larger due to 465 * a non-page-aligned size. Instead just aggregate using 466 * 'size'. 467 */ 468 if (tbp->b_bcount != size) 469 printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); 470 if (tbp->b_bufsize != size) 471 printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); 472 bp->b_bcount += size; 473 bp->b_bufsize += size; 474 } 475 476 /* 477 * Fully valid pages in the cluster are already good and do not need 478 * to be re-read from disk. Replace the page with bogus_page 479 */ 480 for (j = 0; j < bp->b_xio.xio_npages; j++) { 481 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) == 482 VM_PAGE_BITS_ALL) { 483 bp->b_xio.xio_pages[j] = bogus_page; 484 } 485 } 486 if (bp->b_bufsize > bp->b_kvasize) 487 panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)", 488 bp->b_bufsize, bp->b_kvasize); 489 bp->b_kvasize = bp->b_bufsize; 490 491 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 492 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages); 493 return (bp); 494 } 495 496 /* 497 * Cleanup after a clustered read or write. 498 * This is complicated by the fact that any of the buffers might have 499 * extra memory (if there were no empty buffer headers at allocbuf time) 500 * that we will need to shift around. 501 * 502 * The returned bio is &bp->b_bio1 503 */ 504 void 505 cluster_callback(struct bio *bio) 506 { 507 struct buf *bp = bio->bio_buf; 508 struct buf *tbp; 509 int error = 0; 510 511 /* 512 * Must propogate errors to all the components. 513 */ 514 if (bp->b_flags & B_ERROR) 515 error = bp->b_error; 516 517 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages); 518 /* 519 * Move memory from the large cluster buffer into the component 520 * buffers and mark IO as done on these. Since the memory map 521 * is the same, no actual copying is required. 522 */ 523 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) { 524 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next; 525 if (error) { 526 tbp->b_flags |= B_ERROR; 527 tbp->b_error = error; 528 } else { 529 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 530 tbp->b_flags &= ~(B_ERROR|B_INVAL); 531 /* 532 * XXX the bdwrite()/bqrelse() issued during 533 * cluster building clears B_RELBUF (see bqrelse() 534 * comment). If direct I/O was specified, we have 535 * to restore it here to allow the buffer and VM 536 * to be freed. 537 */ 538 if (tbp->b_flags & B_DIRECT) 539 tbp->b_flags |= B_RELBUF; 540 } 541 biodone(&tbp->b_bio1); 542 } 543 relpbuf(bp, &cluster_pbuf_freecnt); 544 } 545 546 /* 547 * cluster_wbuild_wb: 548 * 549 * Implement modified write build for cluster. 550 * 551 * write_behind = 0 write behind disabled 552 * write_behind = 1 write behind normal (default) 553 * write_behind = 2 write behind backed-off 554 */ 555 556 static __inline int 557 cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) 558 { 559 int r = 0; 560 561 switch(write_behind) { 562 case 2: 563 if (start_lbn < len) 564 break; 565 start_lbn -= len; 566 /* fall through */ 567 case 1: 568 r = cluster_wbuild(vp, size, start_lbn, len); 569 /* fall through */ 570 default: 571 /* fall through */ 572 break; 573 } 574 return(r); 575 } 576 577 /* 578 * Do clustered write for FFS. 579 * 580 * Three cases: 581 * 1. Write is not sequential (write asynchronously) 582 * Write is sequential: 583 * 2. beginning of cluster - begin cluster 584 * 3. middle of a cluster - add to cluster 585 * 4. end of a cluster - asynchronously write cluster 586 */ 587 void 588 cluster_write(struct buf *bp, u_quad_t filesize, int seqcount) 589 { 590 struct vnode *vp; 591 daddr_t lbn; 592 int maxclen, cursize; 593 int lblocksize; 594 int async; 595 596 vp = bp->b_vp; 597 if (vp->v_type == VREG) { 598 async = vp->v_mount->mnt_flag & MNT_ASYNC; 599 lblocksize = vp->v_mount->mnt_stat.f_iosize; 600 } else { 601 async = 0; 602 lblocksize = bp->b_bufsize; 603 } 604 lbn = bp->b_lblkno; 605 KASSERT(bp->b_loffset != NOOFFSET, 606 ("cluster_write: no buffer offset")); 607 608 /* Initialize vnode to beginning of file. */ 609 if (lbn == 0) 610 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 611 612 if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || 613 bp->b_bio2.bio_blkno == (daddr_t)-1 || 614 (bp->b_bio2.bio_blkno != vp->v_lasta + btodb(lblocksize))) { 615 maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; 616 if (vp->v_clen != 0) { 617 /* 618 * Next block is not sequential. 619 * 620 * If we are not writing at end of file, the process 621 * seeked to another point in the file since its last 622 * write, or we have reached our maximum cluster size, 623 * then push the previous cluster. Otherwise try 624 * reallocating to make it sequential. 625 * 626 * Change to algorithm: only push previous cluster if 627 * it was sequential from the point of view of the 628 * seqcount heuristic, otherwise leave the buffer 629 * intact so we can potentially optimize the I/O 630 * later on in the buf_daemon or update daemon 631 * flush. 632 */ 633 cursize = vp->v_lastw - vp->v_cstart + 1; 634 if (((u_quad_t) bp->b_loffset + lblocksize) != filesize || 635 lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { 636 if (!async && seqcount > 0) { 637 cluster_wbuild_wb(vp, lblocksize, 638 vp->v_cstart, cursize); 639 } 640 } else { 641 struct buf **bpp, **endbp; 642 struct cluster_save *buflist; 643 644 buflist = cluster_collectbufs(vp, bp); 645 endbp = &buflist->bs_children 646 [buflist->bs_nchildren - 1]; 647 if (VOP_REALLOCBLKS(vp, buflist)) { 648 /* 649 * Failed, push the previous cluster 650 * if *really* writing sequentially 651 * in the logical file (seqcount > 1), 652 * otherwise delay it in the hopes that 653 * the low level disk driver can 654 * optimize the write ordering. 655 */ 656 for (bpp = buflist->bs_children; 657 bpp < endbp; bpp++) 658 brelse(*bpp); 659 free(buflist, M_SEGMENT); 660 if (seqcount > 1) { 661 cluster_wbuild_wb(vp, 662 lblocksize, vp->v_cstart, 663 cursize); 664 } 665 } else { 666 /* 667 * Succeeded, keep building cluster. 668 */ 669 for (bpp = buflist->bs_children; 670 bpp <= endbp; bpp++) 671 bdwrite(*bpp); 672 free(buflist, M_SEGMENT); 673 vp->v_lastw = lbn; 674 vp->v_lasta = bp->b_bio2.bio_blkno; 675 return; 676 } 677 } 678 } 679 /* 680 * Consider beginning a cluster. If at end of file, make 681 * cluster as large as possible, otherwise find size of 682 * existing cluster. 683 */ 684 if ((vp->v_type == VREG) && 685 ((u_quad_t) bp->b_loffset + lblocksize) != filesize && 686 (bp->b_bio2.bio_blkno == (daddr_t)-1) && 687 (VOP_BMAP(vp, lbn, NULL, &bp->b_bio2.bio_blkno, &maxclen, NULL) || 688 bp->b_bio2.bio_blkno == (daddr_t)-1)) { 689 bawrite(bp); 690 vp->v_clen = 0; 691 vp->v_lasta = bp->b_bio2.bio_blkno; 692 vp->v_cstart = lbn + 1; 693 vp->v_lastw = lbn; 694 return; 695 } 696 vp->v_clen = maxclen; 697 if (!async && maxclen == 0) { /* I/O not contiguous */ 698 vp->v_cstart = lbn + 1; 699 bawrite(bp); 700 } else { /* Wait for rest of cluster */ 701 vp->v_cstart = lbn; 702 bdwrite(bp); 703 } 704 } else if (lbn == vp->v_cstart + vp->v_clen) { 705 /* 706 * At end of cluster, write it out if seqcount tells us we 707 * are operating sequentially, otherwise let the buf or 708 * update daemon handle it. 709 */ 710 bdwrite(bp); 711 if (seqcount > 1) 712 cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); 713 vp->v_clen = 0; 714 vp->v_cstart = lbn + 1; 715 } else if (vm_page_count_severe()) { 716 /* 717 * We are low on memory, get it going NOW 718 */ 719 bawrite(bp); 720 } else { 721 /* 722 * In the middle of a cluster, so just delay the I/O for now. 723 */ 724 bdwrite(bp); 725 } 726 vp->v_lastw = lbn; 727 vp->v_lasta = bp->b_bio2.bio_blkno; 728 } 729 730 731 /* 732 * This is an awful lot like cluster_rbuild...wish they could be combined. 733 * The last lbn argument is the current block on which I/O is being 734 * performed. Check to see that it doesn't fall in the middle of 735 * the current block (if last_bp == NULL). 736 */ 737 int 738 cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len) 739 { 740 struct buf *bp, *tbp; 741 int i, j; 742 int totalwritten = 0; 743 int dbsize = btodb(size); 744 745 while (len > 0) { 746 crit_enter(); 747 /* 748 * If the buffer is not delayed-write (i.e. dirty), or it 749 * is delayed-write but either locked or inval, it cannot 750 * partake in the clustered write. 751 */ 752 if (((tbp = gbincore(vp, start_lbn)) == NULL) || 753 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 754 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 755 ++start_lbn; 756 --len; 757 crit_exit(); 758 continue; 759 } 760 bremfree(tbp); 761 tbp->b_flags &= ~B_DONE; 762 crit_exit(); 763 764 /* 765 * Extra memory in the buffer, punt on this buffer. 766 * XXX we could handle this in most cases, but we would 767 * have to push the extra memory down to after our max 768 * possible cluster size and then potentially pull it back 769 * up if the cluster was terminated prematurely--too much 770 * hassle. 771 */ 772 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 773 (tbp->b_bcount != tbp->b_bufsize) || 774 (tbp->b_bcount != size) || 775 (len == 1) || 776 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 777 totalwritten += tbp->b_bufsize; 778 bawrite(tbp); 779 ++start_lbn; 780 --len; 781 continue; 782 } 783 784 /* 785 * We got a pbuf to make the cluster in. 786 * so initialise it. 787 */ 788 bp->b_bcount = 0; 789 bp->b_bufsize = 0; 790 bp->b_xio.xio_npages = 0; 791 bp->b_lblkno = tbp->b_lblkno; 792 bp->b_loffset = tbp->b_loffset; 793 bp->b_bio2.bio_blkno = tbp->b_bio2.bio_blkno; 794 795 /* 796 * We are synthesizing a buffer out of vm_page_t's, but 797 * if the block size is not page aligned then the starting 798 * address may not be either. Inherit the b_data offset 799 * from the original buffer. 800 */ 801 bp->b_data = (char *)((vm_offset_t)bp->b_data | 802 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 803 bp->b_flags |= B_CLUSTER | 804 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN)); 805 bp->b_bio1.bio_done = cluster_callback; 806 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 807 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 808 pbgetvp(vp, bp); 809 /* 810 * From this location in the file, scan forward to see 811 * if there are buffers with adjacent data that need to 812 * be written as well. 813 */ 814 for (i = 0; i < len; ++i, ++start_lbn) { 815 if (i != 0) { /* If not the first buffer */ 816 crit_enter(); 817 /* 818 * If the adjacent data is not even in core it 819 * can't need to be written. 820 */ 821 if ((tbp = gbincore(vp, start_lbn)) == NULL) { 822 crit_exit(); 823 break; 824 } 825 826 /* 827 * If it IS in core, but has different 828 * characteristics, or is locked (which 829 * means it could be undergoing a background 830 * I/O or be in a weird state), then don't 831 * cluster with it. 832 */ 833 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 834 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 835 != (B_DELWRI | B_CLUSTEROK | 836 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 837 (tbp->b_flags & B_LOCKED) || 838 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 839 crit_exit(); 840 break; 841 } 842 843 /* 844 * Check that the combined cluster 845 * would make sense with regard to pages 846 * and would not be too large 847 */ 848 if ((tbp->b_bcount != size) || 849 ((bp->b_bio2.bio_blkno + (dbsize * i)) != 850 tbp->b_bio2.bio_blkno) || 851 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) > 852 (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { 853 BUF_UNLOCK(tbp); 854 crit_exit(); 855 break; 856 } 857 /* 858 * Ok, it's passed all the tests, 859 * so remove it from the free list 860 * and mark it busy. We will use it. 861 */ 862 bremfree(tbp); 863 tbp->b_flags &= ~B_DONE; 864 crit_exit(); 865 } /* end of code for non-first buffers only */ 866 867 /* 868 * check for latent dependencies to be handled 869 */ 870 if (LIST_FIRST(&tbp->b_dep) != NULL && bioops.io_start) 871 (*bioops.io_start)(tbp); 872 873 /* 874 * If the IO is via the VM then we do some 875 * special VM hackery (yuck). Since the buffer's 876 * block size may not be page-aligned it is possible 877 * for a page to be shared between two buffers. We 878 * have to get rid of the duplication when building 879 * the cluster. 880 */ 881 if (tbp->b_flags & B_VMIO) { 882 vm_page_t m; 883 884 if (i != 0) { /* if not first buffer */ 885 for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { 886 m = tbp->b_xio.xio_pages[j]; 887 if (m->flags & PG_BUSY) { 888 bqrelse(tbp); 889 goto finishcluster; 890 } 891 } 892 } 893 894 for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { 895 m = tbp->b_xio.xio_pages[j]; 896 vm_page_io_start(m); 897 vm_object_pip_add(m->object, 1); 898 if ((bp->b_xio.xio_npages == 0) || 899 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) { 900 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 901 bp->b_xio.xio_npages++; 902 } 903 } 904 } 905 bp->b_bcount += size; 906 bp->b_bufsize += size; 907 908 crit_enter(); 909 bundirty(tbp); 910 tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR); 911 tbp->b_flags |= B_ASYNC; 912 reassignbuf(tbp, tbp->b_vp); /* put on clean list */ 913 crit_exit(); 914 BUF_KERNPROC(tbp); 915 cluster_append(&bp->b_bio1, tbp); 916 } 917 finishcluster: 918 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 919 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages); 920 if (bp->b_bufsize > bp->b_kvasize) 921 panic( 922 "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", 923 bp->b_bufsize, bp->b_kvasize); 924 bp->b_kvasize = bp->b_bufsize; 925 totalwritten += bp->b_bufsize; 926 bp->b_dirtyoff = 0; 927 bp->b_dirtyend = bp->b_bufsize; 928 bawrite(bp); 929 930 len -= i; 931 } 932 return totalwritten; 933 } 934 935 /* 936 * Collect together all the buffers in a cluster. 937 * Plus add one additional buffer. 938 */ 939 static struct cluster_save * 940 cluster_collectbufs(struct vnode *vp, struct buf *last_bp) 941 { 942 struct cluster_save *buflist; 943 struct buf *bp; 944 daddr_t lbn; 945 int i, len; 946 947 len = vp->v_lastw - vp->v_cstart + 1; 948 buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 949 M_SEGMENT, M_WAITOK); 950 buflist->bs_nchildren = 0; 951 buflist->bs_children = (struct buf **) (buflist + 1); 952 for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { 953 (void) bread(vp, lbn, last_bp->b_bcount, &bp); 954 buflist->bs_children[i] = bp; 955 if (bp->b_bio2.bio_blkno == (daddr_t)-1) 956 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_bio2.bio_blkno, 957 NULL, NULL); 958 } 959 buflist->bs_children[i] = bp = last_bp; 960 if (bp->b_bio2.bio_blkno == (daddr_t)-1) 961 VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_bio2.bio_blkno, 962 NULL, NULL); 963 buflist->bs_nchildren = i + 1; 964 return (buflist); 965 } 966 967 void 968 cluster_append(struct bio *bio, struct buf *tbp) 969 { 970 tbp->b_cluster_next = NULL; 971 if (bio->bio_caller_info1.cluster_head == NULL) { 972 bio->bio_caller_info1.cluster_head = tbp; 973 bio->bio_caller_info2.cluster_tail = tbp; 974 } else { 975 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp; 976 bio->bio_caller_info2.cluster_tail = tbp; 977 } 978 } 979 980