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 1.40 2008/07/14 03:09:00 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 blksize); 70 static struct buf * 71 cluster_rbuild (struct vnode *vp, off_t filesize, off_t loffset, 72 off_t doffset, int blksize, 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 blksize, 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 = vmaxiosize(vp) / blksize; 110 maxra = 2 * racluster + (totread / blksize); 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, blksize, 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 * blksize))) { 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 * blksize; 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 / blksize; 171 if (nblks) { 172 int burstbytes; 173 174 if (nblks > racluster) 175 nblks = racluster; 176 177 error = VOP_BMAP(vp, loffset, &doffset, 178 &burstbytes, NULL, BUF_CMD_READ); 179 if (error) 180 goto single_block_read; 181 if (doffset == NOOFFSET) 182 goto single_block_read; 183 if (burstbytes < blksize * 2) 184 goto single_block_read; 185 if (nblks > burstbytes / blksize) 186 nblks = burstbytes / blksize; 187 188 bp = cluster_rbuild(vp, filesize, loffset, 189 doffset, blksize, 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 += blksize; 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 if (bp->b_flags & B_ERROR) { 222 if ((error = bp->b_error) == 0) 223 error = EIO; 224 } else { 225 error = 0; 226 } 227 } 228 229 /* 230 * If we have been doing sequential I/O, then do some read-ahead. 231 * 232 * Only mess with buffers which we can immediately lock. HAMMER 233 * will do device-readahead irrespective of what the blocks 234 * represent. 235 */ 236 rbp = NULL; 237 if (!error && 238 seqcount && 239 loffset < origoffset + seqcount * blksize && 240 loffset + blksize <= filesize 241 ) { 242 int nblksread; 243 int ntoread; 244 int burstbytes; 245 int tmp_error; 246 247 rbp = getblk(vp, loffset, blksize, 248 GETBLK_SZMATCH|GETBLK_NOWAIT, 0); 249 if (rbp == NULL) 250 goto no_read_ahead; 251 if ((rbp->b_flags & B_CACHE)) { 252 bqrelse(rbp); 253 goto no_read_ahead; 254 } 255 256 /* 257 * An error from the read-ahead bmap has nothing to do 258 * with the caller's original request. 259 */ 260 tmp_error = VOP_BMAP(vp, loffset, &doffset, 261 &burstbytes, NULL, BUF_CMD_READ); 262 if (tmp_error || doffset == NOOFFSET) { 263 rbp->b_flags |= B_INVAL; 264 brelse(rbp); 265 rbp = NULL; 266 goto no_read_ahead; 267 } 268 ntoread = burstbytes / blksize; 269 nblksread = (totread + blksize - 1) / blksize; 270 if (seqcount < nblksread) 271 seqcount = nblksread; 272 if (ntoread > seqcount) 273 ntoread = seqcount; 274 275 rbp->b_flags |= B_RAM/* | B_AGE*/; 276 if (burstbytes) { 277 rbp = cluster_rbuild(vp, filesize, loffset, 278 doffset, blksize, 279 ntoread, rbp, 1); 280 } else { 281 rbp->b_bio2.bio_offset = doffset; 282 } 283 #if defined(CLUSTERDEBUG) 284 if (rcluster) { 285 if (bp) 286 kprintf("A+(%lld,%d,%lld,%d) ", 287 rbp->b_loffset, rbp->b_bcount, 288 rbp->b_loffset - origoffset, 289 seqcount); 290 else 291 kprintf("A(%lld,%d,%lld,%d) ", 292 rbp->b_loffset, rbp->b_bcount, 293 rbp->b_loffset - origoffset, 294 seqcount); 295 } 296 #endif 297 rbp->b_flags &= ~(B_ERROR|B_INVAL); 298 rbp->b_flags |= B_ASYNC; 299 rbp->b_cmd = BUF_CMD_READ; 300 301 if ((rbp->b_flags & B_CLUSTER) == 0) 302 vfs_busy_pages(vp, rbp); 303 BUF_KERNPROC(rbp); /* B_ASYNC */ 304 vn_strategy(vp, &rbp->b_bio1); 305 } 306 no_read_ahead: 307 308 if (reqbp) 309 return (biowait(reqbp)); 310 else 311 return (error); 312 } 313 314 /* 315 * If blocks are contiguous on disk, use this to provide clustered 316 * read ahead. We will read as many blocks as possible sequentially 317 * and then parcel them up into logical blocks in the buffer hash table. 318 */ 319 static struct buf * 320 cluster_rbuild(struct vnode *vp, off_t filesize, off_t loffset, 321 off_t doffset, int blksize, int run, struct buf *fbp, int doasync) 322 { 323 struct buf *bp, *tbp; 324 off_t boffset; 325 int i, j; 326 int maxiosize = vmaxiosize(vp); 327 328 /* 329 * avoid a division 330 */ 331 while (loffset + run * blksize > filesize) { 332 --run; 333 } 334 335 tbp = fbp; 336 tbp->b_bio2.bio_offset = doffset; 337 if((tbp->b_flags & B_MALLOC) || 338 ((tbp->b_flags & B_VMIO) == 0) || (run <= 1)) { 339 return tbp; 340 } 341 342 bp = trypbuf(&cluster_pbuf_freecnt); 343 if (bp == NULL) 344 return tbp; 345 346 /* 347 * We are synthesizing a buffer out of vm_page_t's, but 348 * if the block size is not page aligned then the starting 349 * address may not be either. Inherit the b_data offset 350 * from the original buffer. 351 */ 352 bp->b_data = (char *)((vm_offset_t)bp->b_data | 353 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 354 bp->b_flags |= B_ASYNC | B_CLUSTER | B_VMIO; 355 bp->b_cmd = BUF_CMD_READ; 356 bp->b_bio1.bio_done = cluster_callback; 357 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 358 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 359 bp->b_loffset = loffset; 360 bp->b_bio2.bio_offset = doffset; 361 KASSERT(bp->b_loffset != NOOFFSET, 362 ("cluster_rbuild: no buffer offset")); 363 364 bp->b_bcount = 0; 365 bp->b_bufsize = 0; 366 bp->b_xio.xio_npages = 0; 367 368 for (boffset = doffset, i = 0; i < run; ++i, boffset += blksize) { 369 if (i) { 370 if ((bp->b_xio.xio_npages * PAGE_SIZE) + 371 round_page(blksize) > maxiosize) { 372 break; 373 } 374 375 /* 376 * Shortcut some checks and try to avoid buffers that 377 * would block in the lock. The same checks have to 378 * be made again after we officially get the buffer. 379 */ 380 tbp = getblk(vp, loffset + i * blksize, blksize, 381 GETBLK_SZMATCH|GETBLK_NOWAIT, 0); 382 if (tbp == NULL) 383 break; 384 for (j = 0; j < tbp->b_xio.xio_npages; j++) { 385 if (tbp->b_xio.xio_pages[j]->valid) 386 break; 387 } 388 if (j != tbp->b_xio.xio_npages) { 389 bqrelse(tbp); 390 break; 391 } 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 (LIST_FIRST(&tbp->b_dep) != NULL && 403 buf_checkread(tbp)) 404 ) { 405 bqrelse(tbp); 406 break; 407 } 408 409 /* 410 * The buffer must be completely invalid in order to 411 * take part in the cluster. If it is partially valid 412 * then we stop. 413 */ 414 for (j = 0;j < tbp->b_xio.xio_npages; j++) { 415 if (tbp->b_xio.xio_pages[j]->valid) 416 break; 417 } 418 if (j != tbp->b_xio.xio_npages) { 419 bqrelse(tbp); 420 break; 421 } 422 423 /* 424 * Set a read-ahead mark as appropriate 425 */ 426 if (i == 1 || i == (run - 1)) 427 tbp->b_flags |= B_RAM; 428 429 /* 430 * Depress the priority of buffers not explicitly 431 * requested. 432 */ 433 /* tbp->b_flags |= B_AGE; */ 434 435 /* 436 * Set the block number if it isn't set, otherwise 437 * if it is make sure it matches the block number we 438 * expect. 439 */ 440 if (tbp->b_bio2.bio_offset == NOOFFSET) { 441 tbp->b_bio2.bio_offset = boffset; 442 } else if (tbp->b_bio2.bio_offset != boffset) { 443 brelse(tbp); 444 break; 445 } 446 } 447 /* 448 * The first buffer is setup async if doasync is specified. 449 * All other buffers in the cluster are setup async. This 450 * way the caller can decide how to deal with the requested 451 * buffer. 452 */ 453 if (i || doasync) 454 tbp->b_flags |= B_ASYNC; 455 tbp->b_cmd = BUF_CMD_READ; 456 BUF_KERNPROC(tbp); 457 cluster_append(&bp->b_bio1, tbp); 458 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 459 vm_page_t m; 460 m = tbp->b_xio.xio_pages[j]; 461 vm_page_io_start(m); 462 vm_object_pip_add(m->object, 1); 463 if ((bp->b_xio.xio_npages == 0) || 464 (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) { 465 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 466 bp->b_xio.xio_npages++; 467 } 468 if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) 469 tbp->b_xio.xio_pages[j] = bogus_page; 470 } 471 /* 472 * XXX shouldn't this be += size for both, like in 473 * cluster_wbuild()? 474 * 475 * Don't inherit tbp->b_bufsize as it may be larger due to 476 * a non-page-aligned size. Instead just aggregate using 477 * 'size'. 478 */ 479 if (tbp->b_bcount != blksize) 480 kprintf("warning: tbp->b_bcount wrong %d vs %d\n", tbp->b_bcount, blksize); 481 if (tbp->b_bufsize != blksize) 482 kprintf("warning: tbp->b_bufsize wrong %d vs %d\n", tbp->b_bufsize, blksize); 483 bp->b_bcount += blksize; 484 bp->b_bufsize += blksize; 485 } 486 487 /* 488 * Fully valid pages in the cluster are already good and do not need 489 * to be re-read from disk. Replace the page with bogus_page 490 */ 491 for (j = 0; j < bp->b_xio.xio_npages; j++) { 492 if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) == 493 VM_PAGE_BITS_ALL) { 494 bp->b_xio.xio_pages[j] = bogus_page; 495 } 496 } 497 if (bp->b_bufsize > bp->b_kvasize) { 498 panic("cluster_rbuild: b_bufsize(%d) > b_kvasize(%d)", 499 bp->b_bufsize, bp->b_kvasize); 500 } 501 502 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 503 (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages); 504 return (bp); 505 } 506 507 /* 508 * Cleanup after a clustered read or write. 509 * This is complicated by the fact that any of the buffers might have 510 * extra memory (if there were no empty buffer headers at allocbuf time) 511 * that we will need to shift around. 512 * 513 * The returned bio is &bp->b_bio1 514 */ 515 void 516 cluster_callback(struct bio *bio) 517 { 518 struct buf *bp = bio->bio_buf; 519 struct buf *tbp; 520 int error = 0; 521 522 /* 523 * Must propogate errors to all the components. A short read (EOF) 524 * is a critical error. 525 */ 526 if (bp->b_flags & B_ERROR) { 527 error = bp->b_error; 528 } else if (bp->b_bcount != bp->b_bufsize) { 529 panic("cluster_callback: unexpected EOF on cluster %p!", bio); 530 } 531 532 pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages); 533 /* 534 * Move memory from the large cluster buffer into the component 535 * buffers and mark IO as done on these. Since the memory map 536 * is the same, no actual copying is required. 537 */ 538 while ((tbp = bio->bio_caller_info1.cluster_head) != NULL) { 539 bio->bio_caller_info1.cluster_head = tbp->b_cluster_next; 540 if (error) { 541 tbp->b_flags |= B_ERROR; 542 tbp->b_error = error; 543 } else { 544 tbp->b_dirtyoff = tbp->b_dirtyend = 0; 545 tbp->b_flags &= ~(B_ERROR|B_INVAL); 546 /* 547 * XXX the bdwrite()/bqrelse() issued during 548 * cluster building clears B_RELBUF (see bqrelse() 549 * comment). If direct I/O was specified, we have 550 * to restore it here to allow the buffer and VM 551 * to be freed. 552 */ 553 if (tbp->b_flags & B_DIRECT) 554 tbp->b_flags |= B_RELBUF; 555 } 556 biodone(&tbp->b_bio1); 557 } 558 relpbuf(bp, &cluster_pbuf_freecnt); 559 } 560 561 /* 562 * cluster_wbuild_wb: 563 * 564 * Implement modified write build for cluster. 565 * 566 * write_behind = 0 write behind disabled 567 * write_behind = 1 write behind normal (default) 568 * write_behind = 2 write behind backed-off 569 */ 570 571 static __inline int 572 cluster_wbuild_wb(struct vnode *vp, int blksize, off_t start_loffset, int len) 573 { 574 int r = 0; 575 576 switch(write_behind) { 577 case 2: 578 if (start_loffset < len) 579 break; 580 start_loffset -= len; 581 /* fall through */ 582 case 1: 583 r = cluster_wbuild(vp, blksize, start_loffset, len); 584 /* fall through */ 585 default: 586 /* fall through */ 587 break; 588 } 589 return(r); 590 } 591 592 /* 593 * Do clustered write for FFS. 594 * 595 * Three cases: 596 * 1. Write is not sequential (write asynchronously) 597 * Write is sequential: 598 * 2. beginning of cluster - begin cluster 599 * 3. middle of a cluster - add to cluster 600 * 4. end of a cluster - asynchronously write cluster 601 */ 602 void 603 cluster_write(struct buf *bp, off_t filesize, int blksize, int seqcount) 604 { 605 struct vnode *vp; 606 off_t loffset; 607 int maxclen, cursize; 608 int async; 609 610 vp = bp->b_vp; 611 if (vp->v_type == VREG) 612 async = vp->v_mount->mnt_flag & MNT_ASYNC; 613 else 614 async = 0; 615 loffset = bp->b_loffset; 616 KASSERT(bp->b_loffset != NOOFFSET, 617 ("cluster_write: no buffer offset")); 618 619 /* Initialize vnode to beginning of file. */ 620 if (loffset == 0) 621 vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; 622 623 if (vp->v_clen == 0 || loffset != vp->v_lastw + blksize || 624 bp->b_bio2.bio_offset == NOOFFSET || 625 (bp->b_bio2.bio_offset != vp->v_lasta + blksize)) { 626 maxclen = vmaxiosize(vp); 627 if (vp->v_clen != 0) { 628 /* 629 * Next block is not sequential. 630 * 631 * If we are not writing at end of file, the process 632 * seeked to another point in the file since its last 633 * write, or we have reached our maximum cluster size, 634 * then push the previous cluster. Otherwise try 635 * reallocating to make it sequential. 636 * 637 * Change to algorithm: only push previous cluster if 638 * it was sequential from the point of view of the 639 * seqcount heuristic, otherwise leave the buffer 640 * intact so we can potentially optimize the I/O 641 * later on in the buf_daemon or update daemon 642 * flush. 643 */ 644 cursize = vp->v_lastw - vp->v_cstart + blksize; 645 if (bp->b_loffset + blksize != filesize || 646 loffset != vp->v_lastw + blksize || vp->v_clen <= cursize) { 647 if (!async && seqcount > 0) { 648 cluster_wbuild_wb(vp, blksize, 649 vp->v_cstart, cursize); 650 } 651 } else { 652 struct buf **bpp, **endbp; 653 struct cluster_save *buflist; 654 655 buflist = cluster_collectbufs(vp, bp, blksize); 656 endbp = &buflist->bs_children 657 [buflist->bs_nchildren - 1]; 658 if (VOP_REALLOCBLKS(vp, buflist)) { 659 /* 660 * Failed, push the previous cluster 661 * if *really* writing sequentially 662 * in the logical file (seqcount > 1), 663 * otherwise delay it in the hopes that 664 * the low level disk driver can 665 * optimize the write ordering. 666 */ 667 for (bpp = buflist->bs_children; 668 bpp < endbp; bpp++) 669 brelse(*bpp); 670 kfree(buflist, M_SEGMENT); 671 if (seqcount > 1) { 672 cluster_wbuild_wb(vp, 673 blksize, vp->v_cstart, 674 cursize); 675 } 676 } else { 677 /* 678 * Succeeded, keep building cluster. 679 */ 680 for (bpp = buflist->bs_children; 681 bpp <= endbp; bpp++) 682 bdwrite(*bpp); 683 kfree(buflist, M_SEGMENT); 684 vp->v_lastw = loffset; 685 vp->v_lasta = bp->b_bio2.bio_offset; 686 return; 687 } 688 } 689 } 690 /* 691 * Consider beginning a cluster. If at end of file, make 692 * cluster as large as possible, otherwise find size of 693 * existing cluster. 694 */ 695 if ((vp->v_type == VREG) && 696 bp->b_loffset + blksize != filesize && 697 (bp->b_bio2.bio_offset == NOOFFSET) && 698 (VOP_BMAP(vp, loffset, &bp->b_bio2.bio_offset, &maxclen, NULL, BUF_CMD_WRITE) || 699 bp->b_bio2.bio_offset == NOOFFSET)) { 700 bawrite(bp); 701 vp->v_clen = 0; 702 vp->v_lasta = bp->b_bio2.bio_offset; 703 vp->v_cstart = loffset + blksize; 704 vp->v_lastw = loffset; 705 return; 706 } 707 if (maxclen > blksize) 708 vp->v_clen = maxclen - blksize; 709 else 710 vp->v_clen = 0; 711 if (!async && vp->v_clen == 0) { /* I/O not contiguous */ 712 vp->v_cstart = loffset + blksize; 713 bawrite(bp); 714 } else { /* Wait for rest of cluster */ 715 vp->v_cstart = loffset; 716 bdwrite(bp); 717 } 718 } else if (loffset == vp->v_cstart + vp->v_clen) { 719 /* 720 * At end of cluster, write it out if seqcount tells us we 721 * are operating sequentially, otherwise let the buf or 722 * update daemon handle it. 723 */ 724 bdwrite(bp); 725 if (seqcount > 1) 726 cluster_wbuild_wb(vp, blksize, vp->v_cstart, 727 vp->v_clen + blksize); 728 vp->v_clen = 0; 729 vp->v_cstart = loffset + blksize; 730 } else if (vm_page_count_severe()) { 731 /* 732 * We are low on memory, get it going NOW 733 */ 734 bawrite(bp); 735 } else { 736 /* 737 * In the middle of a cluster, so just delay the I/O for now. 738 */ 739 bdwrite(bp); 740 } 741 vp->v_lastw = loffset; 742 vp->v_lasta = bp->b_bio2.bio_offset; 743 } 744 745 746 /* 747 * This is an awful lot like cluster_rbuild...wish they could be combined. 748 * The last lbn argument is the current block on which I/O is being 749 * performed. Check to see that it doesn't fall in the middle of 750 * the current block (if last_bp == NULL). 751 */ 752 int 753 cluster_wbuild(struct vnode *vp, int blksize, off_t start_loffset, int bytes) 754 { 755 struct buf *bp, *tbp; 756 int i, j; 757 int totalwritten = 0; 758 int maxiosize = vmaxiosize(vp); 759 760 while (bytes > 0) { 761 crit_enter(); 762 /* 763 * If the buffer is not delayed-write (i.e. dirty), or it 764 * is delayed-write but either locked or inval, it cannot 765 * partake in the clustered write. 766 */ 767 if (((tbp = findblk(vp, start_loffset)) == NULL) || 768 ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || 769 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) || 770 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 771 start_loffset += blksize; 772 bytes -= blksize; 773 crit_exit(); 774 continue; 775 } 776 bremfree(tbp); 777 KKASSERT(tbp->b_cmd == BUF_CMD_DONE); 778 crit_exit(); 779 780 /* 781 * Extra memory in the buffer, punt on this buffer. 782 * XXX we could handle this in most cases, but we would 783 * have to push the extra memory down to after our max 784 * possible cluster size and then potentially pull it back 785 * up if the cluster was terminated prematurely--too much 786 * hassle. 787 */ 788 if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || 789 (tbp->b_bcount != tbp->b_bufsize) || 790 (tbp->b_bcount != blksize) || 791 (bytes == blksize) || 792 ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { 793 totalwritten += tbp->b_bufsize; 794 bawrite(tbp); 795 start_loffset += blksize; 796 bytes -= blksize; 797 continue; 798 } 799 800 /* 801 * Set up the pbuf. Track our append point with b_bcount 802 * and b_bufsize. b_bufsize is not used by the device but 803 * our caller uses it to loop clusters and we use it to 804 * detect a premature EOF on the block device. 805 */ 806 bp->b_bcount = 0; 807 bp->b_bufsize = 0; 808 bp->b_xio.xio_npages = 0; 809 bp->b_loffset = tbp->b_loffset; 810 bp->b_bio2.bio_offset = tbp->b_bio2.bio_offset; 811 812 /* 813 * We are synthesizing a buffer out of vm_page_t's, but 814 * if the block size is not page aligned then the starting 815 * address may not be either. Inherit the b_data offset 816 * from the original buffer. 817 */ 818 bp->b_data = (char *)((vm_offset_t)bp->b_data | 819 ((vm_offset_t)tbp->b_data & PAGE_MASK)); 820 bp->b_flags &= ~B_ERROR; 821 bp->b_flags |= B_CLUSTER | B_BNOCLIP | 822 (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT)); 823 bp->b_bio1.bio_done = cluster_callback; 824 bp->b_bio1.bio_caller_info1.cluster_head = NULL; 825 bp->b_bio1.bio_caller_info2.cluster_tail = NULL; 826 /* 827 * From this location in the file, scan forward to see 828 * if there are buffers with adjacent data that need to 829 * be written as well. 830 */ 831 for (i = 0; i < bytes; (i += blksize), (start_loffset += blksize)) { 832 if (i != 0) { /* If not the first buffer */ 833 crit_enter(); 834 /* 835 * If the adjacent data is not even in core it 836 * can't need to be written. 837 */ 838 if ((tbp = findblk(vp, start_loffset)) == NULL) { 839 crit_exit(); 840 break; 841 } 842 843 /* 844 * If it IS in core, but has different 845 * characteristics, or is locked (which 846 * means it could be undergoing a background 847 * I/O or be in a weird state), then don't 848 * cluster with it. 849 */ 850 if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | 851 B_INVAL | B_DELWRI | B_NEEDCOMMIT)) 852 != (B_DELWRI | B_CLUSTEROK | 853 (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || 854 (tbp->b_flags & B_LOCKED) || 855 (LIST_FIRST(&tbp->b_dep) != NULL && buf_checkwrite(tbp)) || 856 BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { 857 crit_exit(); 858 break; 859 } 860 861 /* 862 * Check that the combined cluster 863 * would make sense with regard to pages 864 * and would not be too large 865 */ 866 if ((tbp->b_bcount != blksize) || 867 ((bp->b_bio2.bio_offset + i) != 868 tbp->b_bio2.bio_offset) || 869 ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) > 870 (maxiosize / PAGE_SIZE))) { 871 BUF_UNLOCK(tbp); 872 crit_exit(); 873 break; 874 } 875 /* 876 * Ok, it's passed all the tests, 877 * so remove it from the free list 878 * and mark it busy. We will use it. 879 */ 880 bremfree(tbp); 881 KKASSERT(tbp->b_cmd == BUF_CMD_DONE); 882 crit_exit(); 883 } /* end of code for non-first buffers only */ 884 885 /* 886 * If the IO is via the VM then we do some 887 * special VM hackery (yuck). Since the buffer's 888 * block size may not be page-aligned it is possible 889 * for a page to be shared between two buffers. We 890 * have to get rid of the duplication when building 891 * the cluster. 892 */ 893 if (tbp->b_flags & B_VMIO) { 894 vm_page_t m; 895 896 if (i != 0) { /* if not first buffer */ 897 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 898 m = tbp->b_xio.xio_pages[j]; 899 if (m->flags & PG_BUSY) { 900 bqrelse(tbp); 901 goto finishcluster; 902 } 903 } 904 } 905 906 for (j = 0; j < tbp->b_xio.xio_npages; ++j) { 907 m = tbp->b_xio.xio_pages[j]; 908 vm_page_io_start(m); 909 vm_object_pip_add(m->object, 1); 910 if ((bp->b_xio.xio_npages == 0) || 911 (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) { 912 bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; 913 bp->b_xio.xio_npages++; 914 } 915 } 916 } 917 bp->b_bcount += blksize; 918 bp->b_bufsize += blksize; 919 920 crit_enter(); 921 bundirty(tbp); 922 tbp->b_flags &= ~B_ERROR; 923 tbp->b_flags |= B_ASYNC; 924 tbp->b_cmd = BUF_CMD_WRITE; 925 crit_exit(); 926 BUF_KERNPROC(tbp); 927 cluster_append(&bp->b_bio1, tbp); 928 929 /* 930 * check for latent dependencies to be handled 931 */ 932 if (LIST_FIRST(&tbp->b_dep) != NULL) 933 buf_start(tbp); 934 } 935 finishcluster: 936 pmap_qenter(trunc_page((vm_offset_t) bp->b_data), 937 (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages); 938 if (bp->b_bufsize > bp->b_kvasize) { 939 panic( 940 "cluster_wbuild: b_bufsize(%d) > b_kvasize(%d)\n", 941 bp->b_bufsize, bp->b_kvasize); 942 } 943 totalwritten += bp->b_bufsize; 944 bp->b_dirtyoff = 0; 945 bp->b_dirtyend = bp->b_bufsize; 946 bp->b_flags |= B_ASYNC; 947 bp->b_cmd = BUF_CMD_WRITE; 948 vfs_busy_pages(vp, bp); 949 bp->b_runningbufspace = bp->b_bufsize; 950 if (bp->b_runningbufspace) { 951 runningbufspace += bp->b_runningbufspace; 952 ++runningbufcount; 953 } 954 BUF_KERNPROC(bp); /* B_ASYNC */ 955 vn_strategy(vp, &bp->b_bio1); 956 957 bytes -= i; 958 } 959 return totalwritten; 960 } 961 962 /* 963 * Collect together all the buffers in a cluster. 964 * Plus add one additional buffer. 965 */ 966 static struct cluster_save * 967 cluster_collectbufs(struct vnode *vp, struct buf *last_bp, int blksize) 968 { 969 struct cluster_save *buflist; 970 struct buf *bp; 971 off_t loffset; 972 int i, len; 973 974 len = (int)(vp->v_lastw - vp->v_cstart + blksize) / blksize; 975 buflist = kmalloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), 976 M_SEGMENT, M_WAITOK); 977 buflist->bs_nchildren = 0; 978 buflist->bs_children = (struct buf **) (buflist + 1); 979 for (loffset = vp->v_cstart, i = 0; i < len; (loffset += blksize), i++) { 980 (void) bread(vp, loffset, last_bp->b_bcount, &bp); 981 buflist->bs_children[i] = bp; 982 if (bp->b_bio2.bio_offset == NOOFFSET) { 983 VOP_BMAP(bp->b_vp, bp->b_loffset, 984 &bp->b_bio2.bio_offset, 985 NULL, NULL, BUF_CMD_WRITE); 986 } 987 } 988 buflist->bs_children[i] = bp = last_bp; 989 if (bp->b_bio2.bio_offset == NOOFFSET) { 990 VOP_BMAP(bp->b_vp, bp->b_loffset, &bp->b_bio2.bio_offset, 991 NULL, NULL, BUF_CMD_WRITE); 992 } 993 buflist->bs_nchildren = i + 1; 994 return (buflist); 995 } 996 997 void 998 cluster_append(struct bio *bio, struct buf *tbp) 999 { 1000 tbp->b_cluster_next = NULL; 1001 if (bio->bio_caller_info1.cluster_head == NULL) { 1002 bio->bio_caller_info1.cluster_head = tbp; 1003 bio->bio_caller_info2.cluster_tail = tbp; 1004 } else { 1005 bio->bio_caller_info2.cluster_tail->b_cluster_next = tbp; 1006 bio->bio_caller_info2.cluster_tail = tbp; 1007 } 1008 } 1009 1010