1 /*- 2 * Copyright (c) 2013 Peter Grehan <grehan@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/queue.h> 34 #include <sys/errno.h> 35 #include <sys/stat.h> 36 #include <sys/ioctl.h> 37 #include <sys/disk.h> 38 39 #include <assert.h> 40 #include <fcntl.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <pthread.h> 45 #include <pthread_np.h> 46 #include <signal.h> 47 #include <unistd.h> 48 49 #include <machine/atomic.h> 50 51 #include "bhyverun.h" 52 #include "mevent.h" 53 #include "block_if.h" 54 55 #define BLOCKIF_SIG 0xb109b109 56 57 #define BLOCKIF_NUMTHR 8 58 #define BLOCKIF_MAXREQ (64 + BLOCKIF_NUMTHR) 59 60 enum blockop { 61 BOP_READ, 62 BOP_WRITE, 63 BOP_FLUSH, 64 BOP_DELETE 65 }; 66 67 enum blockstat { 68 BST_FREE, 69 BST_BLOCK, 70 BST_PEND, 71 BST_BUSY, 72 BST_DONE 73 }; 74 75 struct blockif_elem { 76 TAILQ_ENTRY(blockif_elem) be_link; 77 struct blockif_req *be_req; 78 enum blockop be_op; 79 enum blockstat be_status; 80 pthread_t be_tid; 81 off_t be_block; 82 }; 83 84 struct blockif_ctxt { 85 int bc_magic; 86 int bc_fd; 87 int bc_ischr; 88 int bc_isgeom; 89 int bc_candelete; 90 int bc_rdonly; 91 off_t bc_size; 92 int bc_sectsz; 93 int bc_psectsz; 94 int bc_psectoff; 95 int bc_closing; 96 pthread_t bc_btid[BLOCKIF_NUMTHR]; 97 pthread_mutex_t bc_mtx; 98 pthread_cond_t bc_cond; 99 100 /* Request elements and free/pending/busy queues */ 101 TAILQ_HEAD(, blockif_elem) bc_freeq; 102 TAILQ_HEAD(, blockif_elem) bc_pendq; 103 TAILQ_HEAD(, blockif_elem) bc_busyq; 104 struct blockif_elem bc_reqs[BLOCKIF_MAXREQ]; 105 }; 106 107 static pthread_once_t blockif_once = PTHREAD_ONCE_INIT; 108 109 struct blockif_sig_elem { 110 pthread_mutex_t bse_mtx; 111 pthread_cond_t bse_cond; 112 int bse_pending; 113 struct blockif_sig_elem *bse_next; 114 }; 115 116 static struct blockif_sig_elem *blockif_bse_head; 117 118 static int 119 blockif_enqueue(struct blockif_ctxt *bc, struct blockif_req *breq, 120 enum blockop op) 121 { 122 struct blockif_elem *be, *tbe; 123 off_t off; 124 int i; 125 126 be = TAILQ_FIRST(&bc->bc_freeq); 127 assert(be != NULL); 128 assert(be->be_status == BST_FREE); 129 TAILQ_REMOVE(&bc->bc_freeq, be, be_link); 130 be->be_req = breq; 131 be->be_op = op; 132 switch (op) { 133 case BOP_READ: 134 case BOP_WRITE: 135 case BOP_DELETE: 136 off = breq->br_offset; 137 for (i = 0; i < breq->br_iovcnt; i++) 138 off += breq->br_iov[i].iov_len; 139 break; 140 default: 141 off = OFF_MAX; 142 } 143 be->be_block = off; 144 TAILQ_FOREACH(tbe, &bc->bc_pendq, be_link) { 145 if (tbe->be_block == breq->br_offset) 146 break; 147 } 148 if (tbe == NULL) { 149 TAILQ_FOREACH(tbe, &bc->bc_busyq, be_link) { 150 if (tbe->be_block == breq->br_offset) 151 break; 152 } 153 } 154 if (tbe == NULL) 155 be->be_status = BST_PEND; 156 else 157 be->be_status = BST_BLOCK; 158 TAILQ_INSERT_TAIL(&bc->bc_pendq, be, be_link); 159 return (be->be_status == BST_PEND); 160 } 161 162 static int 163 blockif_dequeue(struct blockif_ctxt *bc, pthread_t t, struct blockif_elem **bep) 164 { 165 struct blockif_elem *be; 166 167 TAILQ_FOREACH(be, &bc->bc_pendq, be_link) { 168 if (be->be_status == BST_PEND) 169 break; 170 assert(be->be_status == BST_BLOCK); 171 } 172 if (be == NULL) 173 return (0); 174 TAILQ_REMOVE(&bc->bc_pendq, be, be_link); 175 be->be_status = BST_BUSY; 176 be->be_tid = t; 177 TAILQ_INSERT_TAIL(&bc->bc_busyq, be, be_link); 178 *bep = be; 179 return (1); 180 } 181 182 static void 183 blockif_complete(struct blockif_ctxt *bc, struct blockif_elem *be) 184 { 185 struct blockif_elem *tbe; 186 187 if (be->be_status == BST_DONE || be->be_status == BST_BUSY) 188 TAILQ_REMOVE(&bc->bc_busyq, be, be_link); 189 else 190 TAILQ_REMOVE(&bc->bc_pendq, be, be_link); 191 TAILQ_FOREACH(tbe, &bc->bc_pendq, be_link) { 192 if (tbe->be_req->br_offset == be->be_block) 193 tbe->be_status = BST_PEND; 194 } 195 be->be_tid = 0; 196 be->be_status = BST_FREE; 197 be->be_req = NULL; 198 TAILQ_INSERT_TAIL(&bc->bc_freeq, be, be_link); 199 } 200 201 static void 202 blockif_proc(struct blockif_ctxt *bc, struct blockif_elem *be, uint8_t *buf) 203 { 204 struct blockif_req *br; 205 off_t arg[2]; 206 ssize_t clen, len, off, boff, voff; 207 int i, err; 208 209 br = be->be_req; 210 if (br->br_iovcnt <= 1) 211 buf = NULL; 212 err = 0; 213 switch (be->be_op) { 214 case BOP_READ: 215 if (buf == NULL) { 216 if ((len = preadv(bc->bc_fd, br->br_iov, br->br_iovcnt, 217 br->br_offset)) < 0) 218 err = errno; 219 else 220 br->br_resid -= len; 221 break; 222 } 223 i = 0; 224 off = voff = 0; 225 while (br->br_resid > 0) { 226 len = MIN(br->br_resid, MAXPHYS); 227 if (pread(bc->bc_fd, buf, len, br->br_offset + 228 off) < 0) { 229 err = errno; 230 break; 231 } 232 boff = 0; 233 do { 234 clen = MIN(len - boff, br->br_iov[i].iov_len - 235 voff); 236 memcpy(br->br_iov[i].iov_base + voff, 237 buf + boff, clen); 238 if (clen < br->br_iov[i].iov_len - voff) 239 voff += clen; 240 else { 241 i++; 242 voff = 0; 243 } 244 boff += clen; 245 } while (boff < len); 246 off += len; 247 br->br_resid -= len; 248 } 249 break; 250 case BOP_WRITE: 251 if (bc->bc_rdonly) { 252 err = EROFS; 253 break; 254 } 255 if (buf == NULL) { 256 if ((len = pwritev(bc->bc_fd, br->br_iov, br->br_iovcnt, 257 br->br_offset)) < 0) 258 err = errno; 259 else 260 br->br_resid -= len; 261 break; 262 } 263 i = 0; 264 off = voff = 0; 265 while (br->br_resid > 0) { 266 len = MIN(br->br_resid, MAXPHYS); 267 boff = 0; 268 do { 269 clen = MIN(len - boff, br->br_iov[i].iov_len - 270 voff); 271 memcpy(buf + boff, 272 br->br_iov[i].iov_base + voff, clen); 273 if (clen < br->br_iov[i].iov_len - voff) 274 voff += clen; 275 else { 276 i++; 277 voff = 0; 278 } 279 boff += clen; 280 } while (boff < len); 281 if (pwrite(bc->bc_fd, buf, len, br->br_offset + 282 off) < 0) { 283 err = errno; 284 break; 285 } 286 off += len; 287 br->br_resid -= len; 288 } 289 break; 290 case BOP_FLUSH: 291 if (bc->bc_ischr) { 292 if (ioctl(bc->bc_fd, DIOCGFLUSH)) 293 err = errno; 294 } else if (fsync(bc->bc_fd)) 295 err = errno; 296 break; 297 case BOP_DELETE: 298 if (!bc->bc_candelete) 299 err = EOPNOTSUPP; 300 else if (bc->bc_rdonly) 301 err = EROFS; 302 else if (bc->bc_ischr) { 303 arg[0] = br->br_offset; 304 arg[1] = br->br_resid; 305 if (ioctl(bc->bc_fd, DIOCGDELETE, arg)) 306 err = errno; 307 else 308 br->br_resid = 0; 309 } else 310 err = EOPNOTSUPP; 311 break; 312 default: 313 err = EINVAL; 314 break; 315 } 316 317 be->be_status = BST_DONE; 318 319 (*br->br_callback)(br, err); 320 } 321 322 static void * 323 blockif_thr(void *arg) 324 { 325 struct blockif_ctxt *bc; 326 struct blockif_elem *be; 327 pthread_t t; 328 uint8_t *buf; 329 330 bc = arg; 331 if (bc->bc_isgeom) 332 buf = malloc(MAXPHYS); 333 else 334 buf = NULL; 335 t = pthread_self(); 336 337 pthread_mutex_lock(&bc->bc_mtx); 338 for (;;) { 339 while (blockif_dequeue(bc, t, &be)) { 340 pthread_mutex_unlock(&bc->bc_mtx); 341 blockif_proc(bc, be, buf); 342 pthread_mutex_lock(&bc->bc_mtx); 343 blockif_complete(bc, be); 344 } 345 /* Check ctxt status here to see if exit requested */ 346 if (bc->bc_closing) 347 break; 348 pthread_cond_wait(&bc->bc_cond, &bc->bc_mtx); 349 } 350 pthread_mutex_unlock(&bc->bc_mtx); 351 352 if (buf) 353 free(buf); 354 pthread_exit(NULL); 355 return (NULL); 356 } 357 358 static void 359 blockif_sigcont_handler(int signal, enum ev_type type, void *arg) 360 { 361 struct blockif_sig_elem *bse; 362 363 for (;;) { 364 /* 365 * Process the entire list even if not intended for 366 * this thread. 367 */ 368 do { 369 bse = blockif_bse_head; 370 if (bse == NULL) 371 return; 372 } while (!atomic_cmpset_ptr((uintptr_t *)&blockif_bse_head, 373 (uintptr_t)bse, 374 (uintptr_t)bse->bse_next)); 375 376 pthread_mutex_lock(&bse->bse_mtx); 377 bse->bse_pending = 0; 378 pthread_cond_signal(&bse->bse_cond); 379 pthread_mutex_unlock(&bse->bse_mtx); 380 } 381 } 382 383 static void 384 blockif_init(void) 385 { 386 mevent_add(SIGCONT, EVF_SIGNAL, blockif_sigcont_handler, NULL); 387 (void) signal(SIGCONT, SIG_IGN); 388 } 389 390 struct blockif_ctxt * 391 blockif_open(const char *optstr, const char *ident) 392 { 393 char tname[MAXCOMLEN + 1]; 394 char name[MAXPATHLEN]; 395 char *nopt, *xopts, *cp; 396 struct blockif_ctxt *bc; 397 struct stat sbuf; 398 struct diocgattr_arg arg; 399 off_t size, psectsz, psectoff; 400 int extra, fd, i, sectsz; 401 int nocache, sync, ro, candelete, geom, ssopt, pssopt; 402 403 pthread_once(&blockif_once, blockif_init); 404 405 fd = -1; 406 ssopt = 0; 407 nocache = 0; 408 sync = 0; 409 ro = 0; 410 411 /* 412 * The first element in the optstring is always a pathname. 413 * Optional elements follow 414 */ 415 nopt = xopts = strdup(optstr); 416 while (xopts != NULL) { 417 cp = strsep(&xopts, ","); 418 if (cp == nopt) /* file or device pathname */ 419 continue; 420 else if (!strcmp(cp, "nocache")) 421 nocache = 1; 422 else if (!strcmp(cp, "sync") || !strcmp(cp, "direct")) 423 sync = 1; 424 else if (!strcmp(cp, "ro")) 425 ro = 1; 426 else if (sscanf(cp, "sectorsize=%d/%d", &ssopt, &pssopt) == 2) 427 ; 428 else if (sscanf(cp, "sectorsize=%d", &ssopt) == 1) 429 pssopt = ssopt; 430 else { 431 fprintf(stderr, "Invalid device option \"%s\"\n", cp); 432 goto err; 433 } 434 } 435 436 extra = 0; 437 if (nocache) 438 extra |= O_DIRECT; 439 if (sync) 440 extra |= O_SYNC; 441 442 fd = open(nopt, (ro ? O_RDONLY : O_RDWR) | extra); 443 if (fd < 0 && !ro) { 444 /* Attempt a r/w fail with a r/o open */ 445 fd = open(nopt, O_RDONLY | extra); 446 ro = 1; 447 } 448 449 if (fd < 0) { 450 perror("Could not open backing file"); 451 goto err; 452 } 453 454 if (fstat(fd, &sbuf) < 0) { 455 perror("Could not stat backing file"); 456 goto err; 457 } 458 459 /* 460 * Deal with raw devices 461 */ 462 size = sbuf.st_size; 463 sectsz = DEV_BSIZE; 464 psectsz = psectoff = 0; 465 candelete = geom = 0; 466 if (S_ISCHR(sbuf.st_mode)) { 467 if (ioctl(fd, DIOCGMEDIASIZE, &size) < 0 || 468 ioctl(fd, DIOCGSECTORSIZE, §sz)) { 469 perror("Could not fetch dev blk/sector size"); 470 goto err; 471 } 472 assert(size != 0); 473 assert(sectsz != 0); 474 if (ioctl(fd, DIOCGSTRIPESIZE, &psectsz) == 0 && psectsz > 0) 475 ioctl(fd, DIOCGSTRIPEOFFSET, &psectoff); 476 strlcpy(arg.name, "GEOM::candelete", sizeof(arg.name)); 477 arg.len = sizeof(arg.value.i); 478 if (ioctl(fd, DIOCGATTR, &arg) == 0) 479 candelete = arg.value.i; 480 if (ioctl(fd, DIOCGPROVIDERNAME, name) == 0) 481 geom = 1; 482 } else 483 psectsz = sbuf.st_blksize; 484 485 if (ssopt != 0) { 486 if (!powerof2(ssopt) || !powerof2(pssopt) || ssopt < 512 || 487 ssopt > pssopt) { 488 fprintf(stderr, "Invalid sector size %d/%d\n", 489 ssopt, pssopt); 490 goto err; 491 } 492 493 /* 494 * Some backend drivers (e.g. cd0, ada0) require that the I/O 495 * size be a multiple of the device's sector size. 496 * 497 * Validate that the emulated sector size complies with this 498 * requirement. 499 */ 500 if (S_ISCHR(sbuf.st_mode)) { 501 if (ssopt < sectsz || (ssopt % sectsz) != 0) { 502 fprintf(stderr, "Sector size %d incompatible " 503 "with underlying device sector size %d\n", 504 ssopt, sectsz); 505 goto err; 506 } 507 } 508 509 sectsz = ssopt; 510 psectsz = pssopt; 511 psectoff = 0; 512 } 513 514 bc = calloc(1, sizeof(struct blockif_ctxt)); 515 if (bc == NULL) { 516 perror("calloc"); 517 goto err; 518 } 519 520 bc->bc_magic = BLOCKIF_SIG; 521 bc->bc_fd = fd; 522 bc->bc_ischr = S_ISCHR(sbuf.st_mode); 523 bc->bc_isgeom = geom; 524 bc->bc_candelete = candelete; 525 bc->bc_rdonly = ro; 526 bc->bc_size = size; 527 bc->bc_sectsz = sectsz; 528 bc->bc_psectsz = psectsz; 529 bc->bc_psectoff = psectoff; 530 pthread_mutex_init(&bc->bc_mtx, NULL); 531 pthread_cond_init(&bc->bc_cond, NULL); 532 TAILQ_INIT(&bc->bc_freeq); 533 TAILQ_INIT(&bc->bc_pendq); 534 TAILQ_INIT(&bc->bc_busyq); 535 for (i = 0; i < BLOCKIF_MAXREQ; i++) { 536 bc->bc_reqs[i].be_status = BST_FREE; 537 TAILQ_INSERT_HEAD(&bc->bc_freeq, &bc->bc_reqs[i], be_link); 538 } 539 540 for (i = 0; i < BLOCKIF_NUMTHR; i++) { 541 pthread_create(&bc->bc_btid[i], NULL, blockif_thr, bc); 542 snprintf(tname, sizeof(tname), "blk-%s-%d", ident, i); 543 pthread_set_name_np(bc->bc_btid[i], tname); 544 } 545 546 return (bc); 547 err: 548 if (fd >= 0) 549 close(fd); 550 return (NULL); 551 } 552 553 static int 554 blockif_request(struct blockif_ctxt *bc, struct blockif_req *breq, 555 enum blockop op) 556 { 557 int err; 558 559 err = 0; 560 561 pthread_mutex_lock(&bc->bc_mtx); 562 if (!TAILQ_EMPTY(&bc->bc_freeq)) { 563 /* 564 * Enqueue and inform the block i/o thread 565 * that there is work available 566 */ 567 if (blockif_enqueue(bc, breq, op)) 568 pthread_cond_signal(&bc->bc_cond); 569 } else { 570 /* 571 * Callers are not allowed to enqueue more than 572 * the specified blockif queue limit. Return an 573 * error to indicate that the queue length has been 574 * exceeded. 575 */ 576 err = E2BIG; 577 } 578 pthread_mutex_unlock(&bc->bc_mtx); 579 580 return (err); 581 } 582 583 int 584 blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq) 585 { 586 587 assert(bc->bc_magic == BLOCKIF_SIG); 588 return (blockif_request(bc, breq, BOP_READ)); 589 } 590 591 int 592 blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq) 593 { 594 595 assert(bc->bc_magic == BLOCKIF_SIG); 596 return (blockif_request(bc, breq, BOP_WRITE)); 597 } 598 599 int 600 blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq) 601 { 602 603 assert(bc->bc_magic == BLOCKIF_SIG); 604 return (blockif_request(bc, breq, BOP_FLUSH)); 605 } 606 607 int 608 blockif_delete(struct blockif_ctxt *bc, struct blockif_req *breq) 609 { 610 611 assert(bc->bc_magic == BLOCKIF_SIG); 612 return (blockif_request(bc, breq, BOP_DELETE)); 613 } 614 615 int 616 blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq) 617 { 618 struct blockif_elem *be; 619 620 assert(bc->bc_magic == BLOCKIF_SIG); 621 622 pthread_mutex_lock(&bc->bc_mtx); 623 /* 624 * Check pending requests. 625 */ 626 TAILQ_FOREACH(be, &bc->bc_pendq, be_link) { 627 if (be->be_req == breq) 628 break; 629 } 630 if (be != NULL) { 631 /* 632 * Found it. 633 */ 634 blockif_complete(bc, be); 635 pthread_mutex_unlock(&bc->bc_mtx); 636 637 return (0); 638 } 639 640 /* 641 * Check in-flight requests. 642 */ 643 TAILQ_FOREACH(be, &bc->bc_busyq, be_link) { 644 if (be->be_req == breq) 645 break; 646 } 647 if (be == NULL) { 648 /* 649 * Didn't find it. 650 */ 651 pthread_mutex_unlock(&bc->bc_mtx); 652 return (EINVAL); 653 } 654 655 /* 656 * Interrupt the processing thread to force it return 657 * prematurely via it's normal callback path. 658 */ 659 while (be->be_status == BST_BUSY) { 660 struct blockif_sig_elem bse, *old_head; 661 662 pthread_mutex_init(&bse.bse_mtx, NULL); 663 pthread_cond_init(&bse.bse_cond, NULL); 664 665 bse.bse_pending = 1; 666 667 do { 668 old_head = blockif_bse_head; 669 bse.bse_next = old_head; 670 } while (!atomic_cmpset_ptr((uintptr_t *)&blockif_bse_head, 671 (uintptr_t)old_head, 672 (uintptr_t)&bse)); 673 674 pthread_kill(be->be_tid, SIGCONT); 675 676 pthread_mutex_lock(&bse.bse_mtx); 677 while (bse.bse_pending) 678 pthread_cond_wait(&bse.bse_cond, &bse.bse_mtx); 679 pthread_mutex_unlock(&bse.bse_mtx); 680 } 681 682 pthread_mutex_unlock(&bc->bc_mtx); 683 684 /* 685 * The processing thread has been interrupted. Since it's not 686 * clear if the callback has been invoked yet, return EBUSY. 687 */ 688 return (EBUSY); 689 } 690 691 int 692 blockif_close(struct blockif_ctxt *bc) 693 { 694 void *jval; 695 int err, i; 696 697 err = 0; 698 699 assert(bc->bc_magic == BLOCKIF_SIG); 700 701 /* 702 * Stop the block i/o thread 703 */ 704 pthread_mutex_lock(&bc->bc_mtx); 705 bc->bc_closing = 1; 706 pthread_mutex_unlock(&bc->bc_mtx); 707 pthread_cond_broadcast(&bc->bc_cond); 708 for (i = 0; i < BLOCKIF_NUMTHR; i++) 709 pthread_join(bc->bc_btid[i], &jval); 710 711 /* XXX Cancel queued i/o's ??? */ 712 713 /* 714 * Release resources 715 */ 716 bc->bc_magic = 0; 717 close(bc->bc_fd); 718 free(bc); 719 720 return (0); 721 } 722 723 /* 724 * Return virtual C/H/S values for a given block. Use the algorithm 725 * outlined in the VHD specification to calculate values. 726 */ 727 void 728 blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h, uint8_t *s) 729 { 730 off_t sectors; /* total sectors of the block dev */ 731 off_t hcyl; /* cylinders times heads */ 732 uint16_t secpt; /* sectors per track */ 733 uint8_t heads; 734 735 assert(bc->bc_magic == BLOCKIF_SIG); 736 737 sectors = bc->bc_size / bc->bc_sectsz; 738 739 /* Clamp the size to the largest possible with CHS */ 740 if (sectors > 65535UL*16*255) 741 sectors = 65535UL*16*255; 742 743 if (sectors >= 65536UL*16*63) { 744 secpt = 255; 745 heads = 16; 746 hcyl = sectors / secpt; 747 } else { 748 secpt = 17; 749 hcyl = sectors / secpt; 750 heads = (hcyl + 1023) / 1024; 751 752 if (heads < 4) 753 heads = 4; 754 755 if (hcyl >= (heads * 1024) || heads > 16) { 756 secpt = 31; 757 heads = 16; 758 hcyl = sectors / secpt; 759 } 760 if (hcyl >= (heads * 1024)) { 761 secpt = 63; 762 heads = 16; 763 hcyl = sectors / secpt; 764 } 765 } 766 767 *c = hcyl / heads; 768 *h = heads; 769 *s = secpt; 770 } 771 772 /* 773 * Accessors 774 */ 775 off_t 776 blockif_size(struct blockif_ctxt *bc) 777 { 778 779 assert(bc->bc_magic == BLOCKIF_SIG); 780 return (bc->bc_size); 781 } 782 783 int 784 blockif_sectsz(struct blockif_ctxt *bc) 785 { 786 787 assert(bc->bc_magic == BLOCKIF_SIG); 788 return (bc->bc_sectsz); 789 } 790 791 void 792 blockif_psectsz(struct blockif_ctxt *bc, int *size, int *off) 793 { 794 795 assert(bc->bc_magic == BLOCKIF_SIG); 796 *size = bc->bc_psectsz; 797 *off = bc->bc_psectoff; 798 } 799 800 int 801 blockif_queuesz(struct blockif_ctxt *bc) 802 { 803 804 assert(bc->bc_magic == BLOCKIF_SIG); 805 return (BLOCKIF_MAXREQ - 1); 806 } 807 808 int 809 blockif_is_ro(struct blockif_ctxt *bc) 810 { 811 812 assert(bc->bc_magic == BLOCKIF_SIG); 813 return (bc->bc_rdonly); 814 } 815 816 int 817 blockif_candelete(struct blockif_ctxt *bc) 818 { 819 820 assert(bc->bc_magic == BLOCKIF_SIG); 821 return (bc->bc_candelete); 822 } 823