| 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 1.12 2005/02/19 00:47:03 joerg 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 | |
| 73 | static int write_behind = 1; |
| 74 | SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, ""); |
| 75 | |
| 76 | extern vm_page_t bogus_page; |
| 77 | |
| 78 | extern int cluster_pbuf_freecnt; |
| 79 | |
| 80 | /* |
| 81 | * Maximum number of blocks for read-ahead. |
| 82 | */ |
| 83 | #define MAXRA 32 |
| 84 | |
| 85 | /* |
| 86 | * This replaces bread. |
| 87 | */ |
| 88 | int |
| 89 | cluster_read(struct vnode *vp, u_quad_t filesize, daddr_t lblkno, |
| 90 | long size, long totread, int seqcount, struct buf **bpp) |
| 91 | { |
| 92 | struct buf *bp, *rbp, *reqbp; |
| 93 | daddr_t blkno, origblkno; |
| 94 | int error, num_ra; |
| 95 | int i; |
| 96 | int maxra, racluster; |
| 97 | long origtotread; |
| 98 | |
| 99 | error = 0; |
| 100 | |
| 101 | /* |
| 102 | * Try to limit the amount of read-ahead by a few |
| 103 | * ad-hoc parameters. This needs work!!! |
| 104 | */ |
| 105 | racluster = vp->v_mount->mnt_iosize_max / size; |
| 106 | maxra = 2 * racluster + (totread / size); |
| 107 | if (maxra > MAXRA) |
| 108 | maxra = MAXRA; |
| 109 | if (maxra > nbuf/8) |
| 110 | maxra = nbuf/8; |
| 111 | |
| 112 | /* |
| 113 | * get the requested block |
| 114 | */ |
| 115 | *bpp = reqbp = bp = getblk(vp, lblkno, size, 0, 0); |
| 116 | origblkno = lblkno; |
| 117 | origtotread = totread; |
| 118 | |
| 119 | /* |
| 120 | * if it is in the cache, then check to see if the reads have been |
| 121 | * sequential. If they have, then try some read-ahead, otherwise |
| 122 | * back-off on prospective read-aheads. |
| 123 | */ |
| 124 | if (bp->b_flags & B_CACHE) { |
| 125 | if (!seqcount) { |
| 126 | return 0; |
| 127 | } else if ((bp->b_flags & B_RAM) == 0) { |
| 128 | return 0; |
| 129 | } else { |
| 130 | int s; |
| 131 | struct buf *tbp; |
| 132 | bp->b_flags &= ~B_RAM; |
| 133 | /* |
| 134 | * We do the spl here so that there is no window |
| 135 | * between the incore and the b_usecount increment |
| 136 | * below. We opt to keep the spl out of the loop |
| 137 | * for efficiency. |
| 138 | */ |
| 139 | s = splbio(); |
| 140 | for (i = 1; i < maxra; i++) { |
| 141 | |
| 142 | if (!(tbp = incore(vp, lblkno+i))) { |
| 143 | break; |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * Set another read-ahead mark so we know |
| 148 | * to check again. |
| 149 | */ |
| 150 | if (((i % racluster) == (racluster - 1)) || |
| 151 | (i == (maxra - 1))) |
| 152 | tbp->b_flags |= B_RAM; |
| 153 | } |
| 154 | splx(s); |
| 155 | if (i >= maxra) { |
| 156 | return 0; |
| 157 | } |
| 158 | lblkno += i; |
| 159 | } |
| 160 | reqbp = bp = NULL; |
| 161 | } else { |
| 162 | off_t firstread = bp->b_offset; |
| 163 | |
| 164 | KASSERT(bp->b_offset != NOOFFSET, |
| 165 | ("cluster_read: no buffer offset")); |
| 166 | if (firstread + totread > filesize) |
| 167 | totread = filesize - firstread; |
| 168 | if (totread > size) { |
| 169 | int nblks = 0; |
| 170 | int ncontigafter; |
| 171 | while (totread > 0) { |
| 172 | nblks++; |
| 173 | totread -= size; |
| 174 | } |
| 175 | if (nblks == 1) |
| 176 | goto single_block_read; |
| 177 | if (nblks > racluster) |
| 178 | nblks = racluster; |
| 179 | |
| 180 | error = VOP_BMAP(vp, lblkno, NULL, |
| 181 | &blkno, &ncontigafter, NULL); |
| 182 | if (error) |
| 183 | goto single_block_read; |
| 184 | if (blkno == -1) |
| 185 | goto single_block_read; |
| 186 | if (ncontigafter == 0) |
| 187 | goto single_block_read; |
| 188 | if (ncontigafter + 1 < nblks) |
| 189 | nblks = ncontigafter + 1; |
| 190 | |
| 191 | bp = cluster_rbuild(vp, filesize, lblkno, |
| 192 | blkno, size, nblks, bp); |
| 193 | lblkno += (bp->b_bufsize / size); |
| 194 | } else { |
| 195 | single_block_read: |
| 196 | /* |
| 197 | * if it isn't in the cache, then get a chunk from |
| 198 | * disk if sequential, otherwise just get the block. |
| 199 | */ |
| 200 | bp->b_flags |= B_READ | B_RAM; |
| 201 | lblkno += 1; |
| 202 | } |
| 203 | } |
| 204 | |
| 205 | /* |
| 206 | * if we have been doing sequential I/O, then do some read-ahead |
| 207 | */ |
| 208 | rbp = NULL; |
| 209 | if (seqcount && (lblkno < (origblkno + seqcount))) { |
| 210 | /* |
| 211 | * we now build the read-ahead buffer if it is desirable. |
| 212 | */ |
| 213 | if (((u_quad_t)(lblkno + 1) * size) <= filesize && |
| 214 | !(error = VOP_BMAP(vp, lblkno, NULL, &blkno, &num_ra, NULL)) && |
| 215 | blkno != -1) { |
| 216 | int nblksread; |
| 217 | int ntoread = num_ra + 1; |
| 218 | nblksread = (origtotread + size - 1) / size; |
| 219 | if (seqcount < nblksread) |
| 220 | seqcount = nblksread; |
| 221 | if (seqcount < ntoread) |
| 222 | ntoread = seqcount; |
| 223 | if (num_ra) { |
| 224 | rbp = cluster_rbuild(vp, filesize, lblkno, |
| 225 | blkno, size, ntoread, NULL); |
| 226 | } else { |
| 227 | rbp = getblk(vp, lblkno, size, 0, 0); |
| 228 | rbp->b_flags |= B_READ | B_ASYNC | B_RAM; |
| 229 | rbp->b_blkno = blkno; |
| 230 | } |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * handle the synchronous read |
| 236 | */ |
| 237 | if (bp) { |
| 238 | #if defined(CLUSTERDEBUG) |
| 239 | if (rcluster) |
| 240 | printf("S(%ld,%ld,%d) ", |
| 241 | (long)bp->b_lblkno, bp->b_bcount, seqcount); |
| 242 | #endif |
| 243 | if ((bp->b_flags & B_CLUSTER) == 0) { |
| 244 | vfs_busy_pages(bp, 0); |
| 245 | } |
| 246 | bp->b_flags &= ~(B_ERROR|B_INVAL); |
| 247 | if (bp->b_flags & (B_ASYNC|B_CALL)) |
| 248 | BUF_KERNPROC(bp); |
| 249 | error = VOP_STRATEGY(vp, bp); |
| 250 | } |
| 251 | |
| 252 | /* |
| 253 | * and if we have read-aheads, do them too |
| 254 | */ |
| 255 | if (rbp) { |
| 256 | if (error) { |
| 257 | rbp->b_flags &= ~(B_ASYNC | B_READ); |
| 258 | brelse(rbp); |
| 259 | } else if (rbp->b_flags & B_CACHE) { |
| 260 | rbp->b_flags &= ~(B_ASYNC | B_READ); |
| 261 | bqrelse(rbp); |
| 262 | } else { |
| 263 | #if defined(CLUSTERDEBUG) |
| 264 | if (rcluster) { |
| 265 | if (bp) |
| 266 | printf("A+(%ld,%ld,%ld,%d) ", |
| 267 | (long)rbp->b_lblkno, rbp->b_bcount, |
| 268 | (long)(rbp->b_lblkno - origblkno), |
| 269 | seqcount); |
| 270 | else |
| 271 | printf("A(%ld,%ld,%ld,%d) ", |
| 272 | (long)rbp->b_lblkno, rbp->b_bcount, |
| 273 | (long)(rbp->b_lblkno - origblkno), |
| 274 | seqcount); |
| 275 | } |
| 276 | #endif |
| 277 | |
| 278 | if ((rbp->b_flags & B_CLUSTER) == 0) { |
| 279 | vfs_busy_pages(rbp, 0); |
| 280 | } |
| 281 | rbp->b_flags &= ~(B_ERROR|B_INVAL); |
| 282 | if (rbp->b_flags & (B_ASYNC|B_CALL)) |
| 283 | BUF_KERNPROC(rbp); |
| 284 | (void) VOP_STRATEGY(vp, rbp); |
| 285 | } |
| 286 | } |
| 287 | if (reqbp) |
| 288 | return (biowait(reqbp)); |
| 289 | else |
| 290 | return (error); |
| 291 | } |
| 292 | |
| 293 | /* |
| 294 | * If blocks are contiguous on disk, use this to provide clustered |
| 295 | * read ahead. We will read as many blocks as possible sequentially |
| 296 | * and then parcel them up into logical blocks in the buffer hash table. |
| 297 | */ |
| 298 | static struct buf * |
| 299 | cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn, |
| 300 | daddr_t blkno, long size, int run, struct buf *fbp) |
| 301 | { |
| 302 | struct buf *bp, *tbp; |
| 303 | daddr_t bn; |
| 304 | int i, inc, j; |
| 305 | |
| 306 | KASSERT(size == vp->v_mount->mnt_stat.f_iosize, |
| 307 | ("cluster_rbuild: size %ld != filesize %ld\n", |
| 308 | size, vp->v_mount->mnt_stat.f_iosize)); |
| 309 | |
| 310 | /* |
| 311 | * avoid a division |
| 312 | */ |
| 313 | while ((u_quad_t) size * (lbn + run) > filesize) { |
| 314 | --run; |
| 315 | } |
| 316 | |
| 317 | if (fbp) { |
| 318 | tbp = fbp; |
| 319 | tbp->b_flags |= B_READ; |
| 320 | } else { |
| 321 | tbp = getblk(vp, lbn, size, 0, 0); |
| 322 | if (tbp->b_flags & B_CACHE) |
| 323 | return tbp; |
| 324 | tbp->b_flags |= B_ASYNC | B_READ | B_RAM; |
| 325 | } |
| 326 | |
| 327 | tbp->b_blkno = blkno; |
| 328 | if( (tbp->b_flags & B_MALLOC) || |
| 329 | ((tbp->b_flags & B_VMIO) == 0) || (run <= 1) ) |
| 330 | return tbp; |
| 331 | |
| 332 | bp = trypbuf(&cluster_pbuf_freecnt); |
| 333 | if (bp == 0) |
| 334 | return tbp; |
| 335 | |
| 336 | /* |
| 337 | * We are synthesizing a buffer out of vm_page_t's, but |
| 338 | * if the block size is not page aligned then the starting |
| 339 | * address may not be either. Inherit the b_data offset |
| 340 | * from the original buffer. |
| 341 | */ |
| 342 | bp->b_data = (char *)((vm_offset_t)bp->b_data | |
| 343 | ((vm_offset_t)tbp->b_data & PAGE_MASK)); |
| 344 | bp->b_flags = B_ASYNC | B_READ | B_CALL | B_CLUSTER | B_VMIO; |
| 345 | bp->b_iodone = cluster_callback; |
| 346 | bp->b_blkno = blkno; |
| 347 | bp->b_lblkno = lbn; |
| 348 | bp->b_offset = tbp->b_offset; |
| 349 | KASSERT(bp->b_offset != NOOFFSET, ("cluster_rbuild: no buffer offset")); |
| 350 | pbgetvp(vp, bp); |
| 351 | |
| 352 | TAILQ_INIT(&bp->b_cluster.cluster_head); |
| 353 | |
| 354 | bp->b_bcount = 0; |
| 355 | bp->b_bufsize = 0; |
| 356 | bp->b_xio.xio_npages = 0; |
| 357 | |
| 358 | inc = btodb(size); |
| 359 | for (bn = blkno, i = 0; i < run; ++i, bn += inc) { |
| 360 | if (i != 0) { |
| 361 | if ((bp->b_xio.xio_npages * PAGE_SIZE) + |
| 362 | round_page(size) > vp->v_mount->mnt_iosize_max) { |
| 363 | break; |
| 364 | } |
| 365 | |
| 366 | /* |
| 367 | * Shortcut some checks and try to avoid buffers that |
| 368 | * would block in the lock. The same checks have to |
| 369 | * be made again after we officially get the buffer. |
| 370 | */ |
| 371 | if ((tbp = incore(vp, lbn + i)) != NULL) { |
| 372 | if (BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) |
| 373 | break; |
| 374 | BUF_UNLOCK(tbp); |
| 375 | |
| 376 | for (j = 0; j < tbp->b_xio.xio_npages; j++) { |
| 377 | if (tbp->b_xio.xio_pages[j]->valid) |
| 378 | break; |
| 379 | } |
| 380 | |
| 381 | if (j != tbp->b_xio.xio_npages) |
| 382 | break; |
| 383 | |
| 384 | if (tbp->b_bcount != size) |
| 385 | break; |
| 386 | } |
| 387 | |
| 388 | tbp = getblk(vp, lbn + i, size, 0, 0); |
| 389 | |
| 390 | /* |
| 391 | * Stop scanning if the buffer is fuly valid |
| 392 | * (marked B_CACHE), or locked (may be doing a |
| 393 | * background write), or if the buffer is not |
| 394 | * VMIO backed. The clustering code can only deal |
| 395 | * with VMIO-backed buffers. |
| 396 | */ |
| 397 | if ((tbp->b_flags & (B_CACHE|B_LOCKED)) || |
| 398 | (tbp->b_flags & B_VMIO) == 0) { |
| 399 | bqrelse(tbp); |
| 400 | break; |
| 401 | } |
| 402 | |
| 403 | /* |
| 404 | * The buffer must be completely invalid in order to |
| 405 | * take part in the cluster. If it is partially valid |
| 406 | * then we stop. |
| 407 | */ |
| 408 | for (j = 0;j < tbp->b_xio.xio_npages; j++) { |
| 409 | if (tbp->b_xio.xio_pages[j]->valid) |
| 410 | break; |
| 411 | } |
| 412 | if (j != tbp->b_xio.xio_npages) { |
| 413 | bqrelse(tbp); |
| 414 | break; |
| 415 | } |
| 416 | |
| 417 | /* |
| 418 | * Set a read-ahead mark as appropriate |
| 419 | */ |
| 420 | if ((fbp && (i == 1)) || (i == (run - 1))) |
| 421 | tbp->b_flags |= B_RAM; |
| 422 | |
| 423 | /* |
| 424 | * Set the buffer up for an async read (XXX should |
| 425 | * we do this only if we do not wind up brelse()ing?). |
| 426 | * Set the block number if it isn't set, otherwise |
| 427 | * if it is make sure it matches the block number we |
| 428 | * expect. |
| 429 | */ |
| 430 | tbp->b_flags |= B_READ | B_ASYNC; |
| 431 | if (tbp->b_blkno == tbp->b_lblkno) { |
| 432 | tbp->b_blkno = bn; |
| 433 | } else if (tbp->b_blkno != bn) { |
| 434 | brelse(tbp); |
| 435 | break; |
| 436 | } |
| 437 | } |
| 438 | /* |
| 439 | * XXX fbp from caller may not be B_ASYNC, but we are going |
| 440 | * to biodone() it in cluster_callback() anyway |
| 441 | */ |
| 442 | BUF_KERNPROC(tbp); |
| 443 | TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, |
| 444 | tbp, b_cluster.cluster_entry); |
| 445 | for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { |
| 446 | vm_page_t m; |
| 447 | m = tbp->b_xio.xio_pages[j]; |
| 448 | vm_page_io_start(m); |
| 449 | vm_object_pip_add(m->object, 1); |
| 450 | if ((bp->b_xio.xio_npages == 0) || |
| 451 | (bp->b_xio.xio_pages[bp->b_xio.xio_npages-1] != m)) { |
| 452 | bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; |
| 453 | bp->b_xio.xio_npages++; |
| 454 | } |
| 455 | if ((m->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL) |
| 456 | tbp->b_xio.xio_pages[j] = bogus_page; |
| 457 | } |
| 458 | /* |
| 459 | * XXX shouldn't this be += size for both, like in |
| 460 | * cluster_wbuild()? |
| 461 | * |
| 462 | * Don't inherit tbp->b_bufsize as it may be larger due to |
| 463 | * a non-page-aligned size. Instead just aggregate using |
| 464 | * 'size'. |
| 465 | */ |
| 466 | if (tbp->b_bcount != size) |
| 467 | printf("warning: tbp->b_bcount wrong %ld vs %ld\n", tbp->b_bcount, size); |
| 468 | if (tbp->b_bufsize != size) |
| 469 | printf("warning: tbp->b_bufsize wrong %ld vs %ld\n", tbp->b_bufsize, size); |
| 470 | bp->b_bcount += size; |
| 471 | bp->b_bufsize += size; |
| 472 | } |
| 473 | |
| 474 | /* |
| 475 | * Fully valid pages in the cluster are already good and do not need |
| 476 | * to be re-read from disk. Replace the page with bogus_page |
| 477 | */ |
| 478 | for (j = 0; j < bp->b_xio.xio_npages; j++) { |
| 479 | if ((bp->b_xio.xio_pages[j]->valid & VM_PAGE_BITS_ALL) == |
| 480 | VM_PAGE_BITS_ALL) { |
| 481 | bp->b_xio.xio_pages[j] = bogus_page; |
| 482 | } |
| 483 | } |
| 484 | if (bp->b_bufsize > bp->b_kvasize) |
| 485 | panic("cluster_rbuild: b_bufsize(%ld) > b_kvasize(%d)", |
| 486 | bp->b_bufsize, bp->b_kvasize); |
| 487 | bp->b_kvasize = bp->b_bufsize; |
| 488 | |
| 489 | pmap_qenter(trunc_page((vm_offset_t) bp->b_data), |
| 490 | (vm_page_t *)bp->b_xio.xio_pages, bp->b_xio.xio_npages); |
| 491 | return (bp); |
| 492 | } |
| 493 | |
| 494 | /* |
| 495 | * Cleanup after a clustered read or write. |
| 496 | * This is complicated by the fact that any of the buffers might have |
| 497 | * extra memory (if there were no empty buffer headers at allocbuf time) |
| 498 | * that we will need to shift around. |
| 499 | */ |
| 500 | void |
| 501 | cluster_callback(struct buf *bp) |
| 502 | { |
| 503 | struct buf *nbp, *tbp; |
| 504 | int error = 0; |
| 505 | |
| 506 | /* |
| 507 | * Must propogate errors to all the components. |
| 508 | */ |
| 509 | if (bp->b_flags & B_ERROR) |
| 510 | error = bp->b_error; |
| 511 | |
| 512 | pmap_qremove(trunc_page((vm_offset_t) bp->b_data), bp->b_xio.xio_npages); |
| 513 | /* |
| 514 | * Move memory from the large cluster buffer into the component |
| 515 | * buffers and mark IO as done on these. |
| 516 | */ |
| 517 | for (tbp = TAILQ_FIRST(&bp->b_cluster.cluster_head); |
| 518 | tbp; tbp = nbp) { |
| 519 | nbp = TAILQ_NEXT(&tbp->b_cluster, cluster_entry); |
| 520 | if (error) { |
| 521 | tbp->b_flags |= B_ERROR; |
| 522 | tbp->b_error = error; |
| 523 | } else { |
| 524 | tbp->b_dirtyoff = tbp->b_dirtyend = 0; |
| 525 | tbp->b_flags &= ~(B_ERROR|B_INVAL); |
| 526 | /* |
| 527 | * XXX the bdwrite()/bqrelse() issued during |
| 528 | * cluster building clears B_RELBUF (see bqrelse() |
| 529 | * comment). If direct I/O was specified, we have |
| 530 | * to restore it here to allow the buffer and VM |
| 531 | * to be freed. |
| 532 | */ |
| 533 | if (tbp->b_flags & B_DIRECT) |
| 534 | tbp->b_flags |= B_RELBUF; |
| 535 | } |
| 536 | biodone(tbp); |
| 537 | } |
| 538 | relpbuf(bp, &cluster_pbuf_freecnt); |
| 539 | } |
| 540 | |
| 541 | /* |
| 542 | * cluster_wbuild_wb: |
| 543 | * |
| 544 | * Implement modified write build for cluster. |
| 545 | * |
| 546 | * write_behind = 0 write behind disabled |
| 547 | * write_behind = 1 write behind normal (default) |
| 548 | * write_behind = 2 write behind backed-off |
| 549 | */ |
| 550 | |
| 551 | static __inline int |
| 552 | cluster_wbuild_wb(struct vnode *vp, long size, daddr_t start_lbn, int len) |
| 553 | { |
| 554 | int r = 0; |
| 555 | |
| 556 | switch(write_behind) { |
| 557 | case 2: |
| 558 | if (start_lbn < len) |
| 559 | break; |
| 560 | start_lbn -= len; |
| 561 | /* fall through */ |
| 562 | case 1: |
| 563 | r = cluster_wbuild(vp, size, start_lbn, len); |
| 564 | /* fall through */ |
| 565 | default: |
| 566 | /* fall through */ |
| 567 | break; |
| 568 | } |
| 569 | return(r); |
| 570 | } |
| 571 | |
| 572 | /* |
| 573 | * Do clustered write for FFS. |
| 574 | * |
| 575 | * Three cases: |
| 576 | * 1. Write is not sequential (write asynchronously) |
| 577 | * Write is sequential: |
| 578 | * 2. beginning of cluster - begin cluster |
| 579 | * 3. middle of a cluster - add to cluster |
| 580 | * 4. end of a cluster - asynchronously write cluster |
| 581 | */ |
| 582 | void |
| 583 | cluster_write(struct buf *bp, u_quad_t filesize, int seqcount) |
| 584 | { |
| 585 | struct vnode *vp; |
| 586 | daddr_t lbn; |
| 587 | int maxclen, cursize; |
| 588 | int lblocksize; |
| 589 | int async; |
| 590 | |
| 591 | vp = bp->b_vp; |
| 592 | if (vp->v_type == VREG) { |
| 593 | async = vp->v_mount->mnt_flag & MNT_ASYNC; |
| 594 | lblocksize = vp->v_mount->mnt_stat.f_iosize; |
| 595 | } else { |
| 596 | async = 0; |
| 597 | lblocksize = bp->b_bufsize; |
| 598 | } |
| 599 | lbn = bp->b_lblkno; |
| 600 | KASSERT(bp->b_offset != NOOFFSET, ("cluster_write: no buffer offset")); |
| 601 | |
| 602 | /* Initialize vnode to beginning of file. */ |
| 603 | if (lbn == 0) |
| 604 | vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0; |
| 605 | |
| 606 | if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 || |
| 607 | (bp->b_blkno != vp->v_lasta + btodb(lblocksize))) { |
| 608 | maxclen = vp->v_mount->mnt_iosize_max / lblocksize - 1; |
| 609 | if (vp->v_clen != 0) { |
| 610 | /* |
| 611 | * Next block is not sequential. |
| 612 | * |
| 613 | * If we are not writing at end of file, the process |
| 614 | * seeked to another point in the file since its last |
| 615 | * write, or we have reached our maximum cluster size, |
| 616 | * then push the previous cluster. Otherwise try |
| 617 | * reallocating to make it sequential. |
| 618 | * |
| 619 | * Change to algorithm: only push previous cluster if |
| 620 | * it was sequential from the point of view of the |
| 621 | * seqcount heuristic, otherwise leave the buffer |
| 622 | * intact so we can potentially optimize the I/O |
| 623 | * later on in the buf_daemon or update daemon |
| 624 | * flush. |
| 625 | */ |
| 626 | cursize = vp->v_lastw - vp->v_cstart + 1; |
| 627 | if (((u_quad_t) bp->b_offset + lblocksize) != filesize || |
| 628 | lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) { |
| 629 | if (!async && seqcount > 0) { |
| 630 | cluster_wbuild_wb(vp, lblocksize, |
| 631 | vp->v_cstart, cursize); |
| 632 | } |
| 633 | } else { |
| 634 | struct buf **bpp, **endbp; |
| 635 | struct cluster_save *buflist; |
| 636 | |
| 637 | buflist = cluster_collectbufs(vp, bp); |
| 638 | endbp = &buflist->bs_children |
| 639 | [buflist->bs_nchildren - 1]; |
| 640 | if (VOP_REALLOCBLKS(vp, buflist)) { |
| 641 | /* |
| 642 | * Failed, push the previous cluster |
| 643 | * if *really* writing sequentially |
| 644 | * in the logical file (seqcount > 1), |
| 645 | * otherwise delay it in the hopes that |
| 646 | * the low level disk driver can |
| 647 | * optimize the write ordering. |
| 648 | */ |
| 649 | for (bpp = buflist->bs_children; |
| 650 | bpp < endbp; bpp++) |
| 651 | brelse(*bpp); |
| 652 | free(buflist, M_SEGMENT); |
| 653 | if (seqcount > 1) { |
| 654 | cluster_wbuild_wb(vp, |
| 655 | lblocksize, vp->v_cstart, |
| 656 | cursize); |
| 657 | } |
| 658 | } else { |
| 659 | /* |
| 660 | * Succeeded, keep building cluster. |
| 661 | */ |
| 662 | for (bpp = buflist->bs_children; |
| 663 | bpp <= endbp; bpp++) |
| 664 | bdwrite(*bpp); |
| 665 | free(buflist, M_SEGMENT); |
| 666 | vp->v_lastw = lbn; |
| 667 | vp->v_lasta = bp->b_blkno; |
| 668 | return; |
| 669 | } |
| 670 | } |
| 671 | } |
| 672 | /* |
| 673 | * Consider beginning a cluster. If at end of file, make |
| 674 | * cluster as large as possible, otherwise find size of |
| 675 | * existing cluster. |
| 676 | */ |
| 677 | if ((vp->v_type == VREG) && |
| 678 | ((u_quad_t) bp->b_offset + lblocksize) != filesize && |
| 679 | (bp->b_blkno == bp->b_lblkno) && |
| 680 | (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen, NULL) || |
| 681 | bp->b_blkno == -1)) { |
| 682 | bawrite(bp); |
| 683 | vp->v_clen = 0; |
| 684 | vp->v_lasta = bp->b_blkno; |
| 685 | vp->v_cstart = lbn + 1; |
| 686 | vp->v_lastw = lbn; |
| 687 | return; |
| 688 | } |
| 689 | vp->v_clen = maxclen; |
| 690 | if (!async && maxclen == 0) { /* I/O not contiguous */ |
| 691 | vp->v_cstart = lbn + 1; |
| 692 | bawrite(bp); |
| 693 | } else { /* Wait for rest of cluster */ |
| 694 | vp->v_cstart = lbn; |
| 695 | bdwrite(bp); |
| 696 | } |
| 697 | } else if (lbn == vp->v_cstart + vp->v_clen) { |
| 698 | /* |
| 699 | * At end of cluster, write it out if seqcount tells us we |
| 700 | * are operating sequentially, otherwise let the buf or |
| 701 | * update daemon handle it. |
| 702 | */ |
| 703 | bdwrite(bp); |
| 704 | if (seqcount > 1) |
| 705 | cluster_wbuild_wb(vp, lblocksize, vp->v_cstart, vp->v_clen + 1); |
| 706 | vp->v_clen = 0; |
| 707 | vp->v_cstart = lbn + 1; |
| 708 | } else if (vm_page_count_severe()) { |
| 709 | /* |
| 710 | * We are low on memory, get it going NOW |
| 711 | */ |
| 712 | bawrite(bp); |
| 713 | } else { |
| 714 | /* |
| 715 | * In the middle of a cluster, so just delay the I/O for now. |
| 716 | */ |
| 717 | bdwrite(bp); |
| 718 | } |
| 719 | vp->v_lastw = lbn; |
| 720 | vp->v_lasta = bp->b_blkno; |
| 721 | } |
| 722 | |
| 723 | |
| 724 | /* |
| 725 | * This is an awful lot like cluster_rbuild...wish they could be combined. |
| 726 | * The last lbn argument is the current block on which I/O is being |
| 727 | * performed. Check to see that it doesn't fall in the middle of |
| 728 | * the current block (if last_bp == NULL). |
| 729 | */ |
| 730 | int |
| 731 | cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len) |
| 732 | { |
| 733 | struct buf *bp, *tbp; |
| 734 | int i, j, s; |
| 735 | int totalwritten = 0; |
| 736 | int dbsize = btodb(size); |
| 737 | |
| 738 | while (len > 0) { |
| 739 | s = splbio(); |
| 740 | /* |
| 741 | * If the buffer is not delayed-write (i.e. dirty), or it |
| 742 | * is delayed-write but either locked or inval, it cannot |
| 743 | * partake in the clustered write. |
| 744 | */ |
| 745 | if (((tbp = gbincore(vp, start_lbn)) == NULL) || |
| 746 | ((tbp->b_flags & (B_LOCKED | B_INVAL | B_DELWRI)) != B_DELWRI) || |
| 747 | BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { |
| 748 | ++start_lbn; |
| 749 | --len; |
| 750 | splx(s); |
| 751 | continue; |
| 752 | } |
| 753 | bremfree(tbp); |
| 754 | tbp->b_flags &= ~B_DONE; |
| 755 | splx(s); |
| 756 | |
| 757 | /* |
| 758 | * Extra memory in the buffer, punt on this buffer. |
| 759 | * XXX we could handle this in most cases, but we would |
| 760 | * have to push the extra memory down to after our max |
| 761 | * possible cluster size and then potentially pull it back |
| 762 | * up if the cluster was terminated prematurely--too much |
| 763 | * hassle. |
| 764 | */ |
| 765 | if (((tbp->b_flags & (B_CLUSTEROK|B_MALLOC)) != B_CLUSTEROK) || |
| 766 | (tbp->b_bcount != tbp->b_bufsize) || |
| 767 | (tbp->b_bcount != size) || |
| 768 | (len == 1) || |
| 769 | ((bp = getpbuf(&cluster_pbuf_freecnt)) == NULL)) { |
| 770 | totalwritten += tbp->b_bufsize; |
| 771 | bawrite(tbp); |
| 772 | ++start_lbn; |
| 773 | --len; |
| 774 | continue; |
| 775 | } |
| 776 | |
| 777 | /* |
| 778 | * We got a pbuf to make the cluster in. |
| 779 | * so initialise it. |
| 780 | */ |
| 781 | TAILQ_INIT(&bp->b_cluster.cluster_head); |
| 782 | bp->b_bcount = 0; |
| 783 | bp->b_bufsize = 0; |
| 784 | bp->b_xio.xio_npages = 0; |
| 785 | bp->b_blkno = tbp->b_blkno; |
| 786 | bp->b_lblkno = tbp->b_lblkno; |
| 787 | bp->b_offset = tbp->b_offset; |
| 788 | |
| 789 | /* |
| 790 | * We are synthesizing a buffer out of vm_page_t's, but |
| 791 | * if the block size is not page aligned then the starting |
| 792 | * address may not be either. Inherit the b_data offset |
| 793 | * from the original buffer. |
| 794 | */ |
| 795 | bp->b_data = (char *)((vm_offset_t)bp->b_data | |
| 796 | ((vm_offset_t)tbp->b_data & PAGE_MASK)); |
| 797 | bp->b_flags |= B_CALL | B_CLUSTER | |
| 798 | (tbp->b_flags & (B_VMIO | B_NEEDCOMMIT | B_NOWDRAIN)); |
| 799 | bp->b_iodone = cluster_callback; |
| 800 | pbgetvp(vp, bp); |
| 801 | /* |
| 802 | * From this location in the file, scan forward to see |
| 803 | * if there are buffers with adjacent data that need to |
| 804 | * be written as well. |
| 805 | */ |
| 806 | for (i = 0; i < len; ++i, ++start_lbn) { |
| 807 | if (i != 0) { /* If not the first buffer */ |
| 808 | s = splbio(); |
| 809 | /* |
| 810 | * If the adjacent data is not even in core it |
| 811 | * can't need to be written. |
| 812 | */ |
| 813 | if ((tbp = gbincore(vp, start_lbn)) == NULL) { |
| 814 | splx(s); |
| 815 | break; |
| 816 | } |
| 817 | |
| 818 | /* |
| 819 | * If it IS in core, but has different |
| 820 | * characteristics, or is locked (which |
| 821 | * means it could be undergoing a background |
| 822 | * I/O or be in a weird state), then don't |
| 823 | * cluster with it. |
| 824 | */ |
| 825 | if ((tbp->b_flags & (B_VMIO | B_CLUSTEROK | |
| 826 | B_INVAL | B_DELWRI | B_NEEDCOMMIT)) |
| 827 | != (B_DELWRI | B_CLUSTEROK | |
| 828 | (bp->b_flags & (B_VMIO | B_NEEDCOMMIT))) || |
| 829 | (tbp->b_flags & B_LOCKED) || |
| 830 | BUF_LOCK(tbp, LK_EXCLUSIVE | LK_NOWAIT)) { |
| 831 | splx(s); |
| 832 | break; |
| 833 | } |
| 834 | |
| 835 | /* |
| 836 | * Check that the combined cluster |
| 837 | * would make sense with regard to pages |
| 838 | * and would not be too large |
| 839 | */ |
| 840 | if ((tbp->b_bcount != size) || |
| 841 | ((bp->b_blkno + (dbsize * i)) != |
| 842 | tbp->b_blkno) || |
| 843 | ((tbp->b_xio.xio_npages + bp->b_xio.xio_npages) > |
| 844 | (vp->v_mount->mnt_iosize_max / PAGE_SIZE))) { |
| 845 | BUF_UNLOCK(tbp); |
| 846 | splx(s); |
| 847 | break; |
| 848 | } |
| 849 | /* |
| 850 | * Ok, it's passed all the tests, |
| 851 | * so remove it from the free list |
| 852 | * and mark it busy. We will use it. |
| 853 | */ |
| 854 | bremfree(tbp); |
| 855 | tbp->b_flags &= ~B_DONE; |
| 856 | splx(s); |
| 857 | } /* end of code for non-first buffers only */ |
| 858 | /* check for latent dependencies to be handled */ |
| 859 | if ((LIST_FIRST(&tbp->b_dep)) != NULL && |
| 860 | bioops.io_start) |
| 861 | (*bioops.io_start)(tbp); |
| 862 | /* |
| 863 | * If the IO is via the VM then we do some |
| 864 | * special VM hackery (yuck). Since the buffer's |
| 865 | * block size may not be page-aligned it is possible |
| 866 | * for a page to be shared between two buffers. We |
| 867 | * have to get rid of the duplication when building |
| 868 | * the cluster. |
| 869 | */ |
| 870 | if (tbp->b_flags & B_VMIO) { |
| 871 | vm_page_t m; |
| 872 | |
| 873 | if (i != 0) { /* if not first buffer */ |
| 874 | for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { |
| 875 | m = tbp->b_xio.xio_pages[j]; |
| 876 | if (m->flags & PG_BUSY) { |
| 877 | bqrelse(tbp); |
| 878 | goto finishcluster; |
| 879 | } |
| 880 | } |
| 881 | } |
| 882 | |
| 883 | for (j = 0; j < tbp->b_xio.xio_npages; j += 1) { |
| 884 | m = tbp->b_xio.xio_pages[j]; |
| 885 | vm_page_io_start(m); |
| 886 | vm_object_pip_add(m->object, 1); |
| 887 | if ((bp->b_xio.xio_npages == 0) || |
| 888 | (bp->b_xio.xio_pages[bp->b_xio.xio_npages - 1] != m)) { |
| 889 | bp->b_xio.xio_pages[bp->b_xio.xio_npages] = m; |
| 890 | bp->b_xio.xio_npages++; |
| 891 | } |
| 892 | } |
| 893 | } |
| 894 | bp->b_bcount += size; |
| 895 | bp->b_bufsize += size; |
| 896 | |
| 897 | s = splbio(); |
| 898 | bundirty(tbp); |
| 899 | tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR); |
| 900 | tbp->b_flags |= B_ASYNC; |
| 901 | reassignbuf(tbp, tbp->b_vp); /* put on clean list */ |
| 902 | ++tbp->b_vp->v_numoutput; |
| 903 | splx(s); |
| 904 | BUF_KERNPROC(tbp); |
| 905 | TAILQ_INSERT_TAIL(&bp->b_cluster.cluster_head, |
| 906 | tbp, b_cluster.cluster_entry); |
| 907 | } |
| 908 | finishcluster: |
| 909 | pmap_qenter(trunc_page((vm_offset_t) bp->b_data), |
| 910 | (vm_page_t *) bp->b_xio.xio_pages, bp->b_xio.xio_npages); |
| 911 | if (bp->b_bufsize > bp->b_kvasize) |
| 912 | panic( |
| 913 | "cluster_wbuild: b_bufsize(%ld) > b_kvasize(%d)\n", |
| 914 | bp->b_bufsize, bp->b_kvasize); |
| 915 | bp->b_kvasize = bp->b_bufsize; |
| 916 | totalwritten += bp->b_bufsize; |
| 917 | bp->b_dirtyoff = 0; |
| 918 | bp->b_dirtyend = bp->b_bufsize; |
| 919 | bawrite(bp); |
| 920 | |
| 921 | len -= i; |
| 922 | } |
| 923 | return totalwritten; |
| 924 | } |
| 925 | |
| 926 | /* |
| 927 | * Collect together all the buffers in a cluster. |
| 928 | * Plus add one additional buffer. |
| 929 | */ |
| 930 | static struct cluster_save * |
| 931 | cluster_collectbufs(struct vnode *vp, struct buf *last_bp) |
| 932 | { |
| 933 | struct cluster_save *buflist; |
| 934 | struct buf *bp; |
| 935 | daddr_t lbn; |
| 936 | int i, len; |
| 937 | |
| 938 | len = vp->v_lastw - vp->v_cstart + 1; |
| 939 | buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist), |
| 940 | M_SEGMENT, M_WAITOK); |
| 941 | buflist->bs_nchildren = 0; |
| 942 | buflist->bs_children = (struct buf **) (buflist + 1); |
| 943 | for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++) { |
| 944 | (void) bread(vp, lbn, last_bp->b_bcount, &bp); |
| 945 | buflist->bs_children[i] = bp; |
| 946 | if (bp->b_blkno == bp->b_lblkno) |
| 947 | VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, |
| 948 | NULL, NULL); |
| 949 | } |
| 950 | buflist->bs_children[i] = bp = last_bp; |
| 951 | if (bp->b_blkno == bp->b_lblkno) |
| 952 | VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno, |
| 953 | NULL, NULL); |
| 954 | buflist->bs_nchildren = i + 1; |
| 955 | return (buflist); |
| 956 | } |