rumpblk.c revision 1.64.2.3
1 /* $NetBSD: rumpblk.c,v 1.64.2.3 2016/07/26 05:54:40 pgoyette Exp $ */ 2 3 /* 4 * Copyright (c) 2009 Antti Kantee. All Rights Reserved. 5 * 6 * Development of this software was supported by the 7 * Finnish Cultural Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 19 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 21 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 24 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 /* 32 * Block device emulation. Presents a block device interface and 33 * uses rumpuser system calls to satisfy I/O requests. 34 * 35 * We provide fault injection. The driver can be made to fail 36 * I/O occasionally. 37 */ 38 39 #include <sys/cdefs.h> 40 __KERNEL_RCSID(0, "$NetBSD: rumpblk.c,v 1.64.2.3 2016/07/26 05:54:40 pgoyette Exp $"); 41 42 #include <sys/param.h> 43 #include <sys/buf.h> 44 #include <sys/conf.h> 45 #include <sys/condvar.h> 46 #include <sys/disklabel.h> 47 #include <sys/evcnt.h> 48 #include <sys/fcntl.h> 49 #include <sys/kmem.h> 50 #include <sys/malloc.h> 51 #include <sys/queue.h> 52 #include <sys/stat.h> 53 #include <sys/cprng.h> 54 #include <sys/localcount.h> 55 56 #include <rump-sys/kern.h> 57 #include <rump-sys/vfs.h> 58 59 #include <rump/rumpuser.h> 60 61 #if 0 62 #define DPRINTF(x) printf x 63 #else 64 #define DPRINTF(x) 65 #endif 66 67 #define RUMPBLK_SIZE 16 68 static struct rblkdev { 69 char *rblk_path; 70 int rblk_fd; 71 int rblk_mode; 72 73 uint64_t rblk_size; 74 uint64_t rblk_hostoffset; 75 uint64_t rblk_hostsize; 76 int rblk_ftype; 77 78 struct disklabel rblk_label; 79 } minors[RUMPBLK_SIZE]; 80 81 static struct evcnt ev_io_total; 82 static struct evcnt ev_io_async; 83 84 static struct evcnt ev_bwrite_total; 85 static struct evcnt ev_bwrite_async; 86 static struct evcnt ev_bread_total; 87 88 dev_type_open(rumpblk_open); 89 dev_type_close(rumpblk_close); 90 dev_type_read(rumpblk_read); 91 dev_type_write(rumpblk_write); 92 dev_type_ioctl(rumpblk_ioctl); 93 dev_type_strategy(rumpblk_strategy); 94 dev_type_strategy(rumpblk_strategy_fail); 95 dev_type_dump(rumpblk_dump); 96 dev_type_size(rumpblk_size); 97 98 static const struct bdevsw rumpblk_bdevsw = { 99 DEVSW_MODULE_INIT 100 .d_open = rumpblk_open, 101 .d_close = rumpblk_close, 102 .d_strategy = rumpblk_strategy, 103 .d_ioctl = rumpblk_ioctl, 104 .d_dump = nodump, 105 .d_psize = nosize, 106 .d_discard = nodiscard, 107 .d_flag = D_DISK 108 }; 109 110 static const struct bdevsw rumpblk_bdevsw_fail = { 111 DEVSW_MODULE_INIT 112 .d_open = rumpblk_open, 113 .d_close = rumpblk_close, 114 .d_strategy = rumpblk_strategy_fail, 115 .d_ioctl = rumpblk_ioctl, 116 .d_dump = nodump, 117 .d_psize = nosize, 118 .d_discard = nodiscard, 119 .d_flag = D_DISK 120 }; 121 122 static const struct cdevsw rumpblk_cdevsw = { 123 DEVSW_MODULE_INIT 124 .d_open = rumpblk_open, 125 .d_close = rumpblk_close, 126 .d_read = rumpblk_read, 127 .d_write = rumpblk_write, 128 .d_ioctl = rumpblk_ioctl, 129 .d_stop = nostop, 130 .d_tty = notty, 131 .d_poll = nopoll, 132 .d_mmap = nommap, 133 .d_kqfilter = nokqfilter, 134 .d_discard = nodiscard, 135 .d_flag = D_DISK 136 }; 137 138 static int backend_open(struct rblkdev *, const char *); 139 static int backend_close(struct rblkdev *); 140 141 /* fail every n out of BLKFAIL_MAX */ 142 #define BLKFAIL_MAX 10000 143 static int blkfail; 144 static unsigned randstate; 145 static kmutex_t rumpblk_lock; 146 static int sectshift = DEV_BSHIFT; 147 148 static void 149 makedefaultlabel(struct disklabel *lp, off_t size, int part) 150 { 151 int i; 152 153 memset(lp, 0, sizeof(*lp)); 154 155 lp->d_secperunit = size; 156 lp->d_secsize = 1 << sectshift; 157 lp->d_nsectors = size >> sectshift; 158 lp->d_ntracks = 1; 159 lp->d_ncylinders = 1; 160 lp->d_secpercyl = lp->d_nsectors; 161 162 /* oh dear oh dear */ 163 strncpy(lp->d_typename, "rumpd", sizeof(lp->d_typename)); 164 strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname)); 165 166 lp->d_type = DKTYPE_RUMPD; 167 lp->d_rpm = 11; 168 lp->d_interleave = 1; 169 lp->d_flags = 0; 170 171 /* XXX: RAW_PART handling? */ 172 for (i = 0; i < part; i++) { 173 lp->d_partitions[i].p_fstype = FS_UNUSED; 174 } 175 lp->d_partitions[part].p_size = size >> sectshift; 176 lp->d_npartitions = part+1; 177 /* XXX: file system type? */ 178 179 lp->d_magic = DISKMAGIC; 180 lp->d_magic2 = DISKMAGIC; 181 lp->d_checksum = 0; /* XXX */ 182 } 183 184 int 185 rumpblk_init(void) 186 { 187 char buf[64]; 188 devmajor_t rumpblkmaj = RUMPBLK_DEVMAJOR; 189 unsigned tmp; 190 int i; 191 192 mutex_init(&rumpblk_lock, MUTEX_DEFAULT, IPL_NONE); 193 194 if (rumpuser_getparam("RUMP_BLKFAIL", buf, sizeof(buf)) == 0) { 195 blkfail = strtoul(buf, NULL, 10); 196 /* fail everything */ 197 if (blkfail > BLKFAIL_MAX) 198 blkfail = BLKFAIL_MAX; 199 if (rumpuser_getparam("RUMP_BLKFAIL_SEED", 200 buf, sizeof(buf)) == 0) { 201 randstate = strtoul(buf, NULL, 10); 202 } else { 203 randstate = cprng_fast32(); 204 } 205 printf("rumpblk: FAULT INJECTION ACTIVE! fail %d/%d. " 206 "seed %u\n", blkfail, BLKFAIL_MAX, randstate); 207 } else { 208 blkfail = 0; 209 } 210 211 if (rumpuser_getparam("RUMP_BLKSECTSHIFT", buf, sizeof(buf)) == 0) { 212 printf("rumpblk: "); 213 tmp = strtoul(buf, NULL, 10); 214 if (tmp >= DEV_BSHIFT) 215 sectshift = tmp; 216 else 217 printf("RUMP_BLKSECTSHIFT must be least %d (now %d), ", 218 DEV_BSHIFT, tmp); 219 printf("using %d for sector shift (size %d)\n", 220 sectshift, 1<<sectshift); 221 } 222 223 memset(minors, 0, sizeof(minors)); 224 for (i = 0; i < RUMPBLK_SIZE; i++) { 225 minors[i].rblk_fd = -1; 226 } 227 228 evcnt_attach_dynamic(&ev_io_total, EVCNT_TYPE_MISC, NULL, 229 "rumpblk", "I/O reqs"); 230 evcnt_attach_dynamic(&ev_io_async, EVCNT_TYPE_MISC, NULL, 231 "rumpblk", "async I/O"); 232 233 evcnt_attach_dynamic(&ev_bread_total, EVCNT_TYPE_MISC, NULL, 234 "rumpblk", "bytes read"); 235 evcnt_attach_dynamic(&ev_bwrite_total, EVCNT_TYPE_MISC, NULL, 236 "rumpblk", "bytes written"); 237 evcnt_attach_dynamic(&ev_bwrite_async, EVCNT_TYPE_MISC, NULL, 238 "rumpblk", "bytes written async"); 239 240 if (blkfail) { 241 return devsw_attach("rumpblk", 242 &rumpblk_bdevsw_fail, &rumpblkmaj, 243 &rumpblk_cdevsw, &rumpblkmaj); 244 } else { 245 return devsw_attach("rumpblk", 246 &rumpblk_bdevsw, &rumpblkmaj, 247 &rumpblk_cdevsw, &rumpblkmaj); 248 } 249 } 250 251 int 252 rumpblk_register(const char *path, devminor_t *dmin, 253 uint64_t offset, uint64_t size) 254 { 255 struct rblkdev *rblk; 256 uint64_t flen; 257 size_t len; 258 int ftype, error, i; 259 260 /* devices might not report correct size unless they're open */ 261 if ((error = rumpuser_getfileinfo(path, &flen, &ftype)) != 0) 262 return error; 263 264 /* verify host file is of supported type */ 265 if (!(ftype == RUMPUSER_FT_REG 266 || ftype == RUMPUSER_FT_BLK 267 || ftype == RUMPUSER_FT_CHR)) 268 return EINVAL; 269 270 mutex_enter(&rumpblk_lock); 271 for (i = 0; i < RUMPBLK_SIZE; i++) { 272 if (minors[i].rblk_path&&strcmp(minors[i].rblk_path, path)==0) { 273 mutex_exit(&rumpblk_lock); 274 *dmin = i; 275 return 0; 276 } 277 } 278 279 for (i = 0; i < RUMPBLK_SIZE; i++) 280 if (minors[i].rblk_path == NULL) 281 break; 282 if (i == RUMPBLK_SIZE) { 283 mutex_exit(&rumpblk_lock); 284 return EBUSY; 285 } 286 287 rblk = &minors[i]; 288 rblk->rblk_path = __UNCONST("taken"); 289 mutex_exit(&rumpblk_lock); 290 291 len = strlen(path); 292 rblk->rblk_path = malloc(len + 1, M_TEMP, M_WAITOK); 293 strcpy(rblk->rblk_path, path); 294 rblk->rblk_hostoffset = offset; 295 if (size != RUMPBLK_SIZENOTSET) { 296 KASSERT(size + offset <= flen); 297 rblk->rblk_size = size; 298 } else { 299 KASSERT(offset < flen); 300 rblk->rblk_size = flen - offset; 301 } 302 rblk->rblk_hostsize = flen; 303 rblk->rblk_ftype = ftype; 304 makedefaultlabel(&rblk->rblk_label, rblk->rblk_size, i); 305 306 if ((error = backend_open(rblk, path)) != 0) { 307 memset(&rblk->rblk_label, 0, sizeof(rblk->rblk_label)); 308 free(rblk->rblk_path, M_TEMP); 309 rblk->rblk_path = NULL; 310 return error; 311 } 312 313 *dmin = i; 314 return 0; 315 } 316 317 /* 318 * Unregister rumpblk. It's the callers responsibility to make 319 * sure it's no longer in use. 320 */ 321 int 322 rumpblk_deregister(const char *path) 323 { 324 struct rblkdev *rblk; 325 int i; 326 327 mutex_enter(&rumpblk_lock); 328 for (i = 0; i < RUMPBLK_SIZE; i++) { 329 if (minors[i].rblk_path&&strcmp(minors[i].rblk_path, path)==0) { 330 break; 331 } 332 } 333 mutex_exit(&rumpblk_lock); 334 335 if (i == RUMPBLK_SIZE) 336 return ENOENT; 337 338 rblk = &minors[i]; 339 backend_close(rblk); 340 341 free(rblk->rblk_path, M_TEMP); 342 memset(&rblk->rblk_label, 0, sizeof(rblk->rblk_label)); 343 rblk->rblk_path = NULL; 344 345 return 0; 346 } 347 348 /* 349 * Release all backend resources, to be called only when the rump 350 * kernel is being shut down. 351 * This routine does not do a full "fini" since we're going down anyway. 352 */ 353 void 354 rumpblk_fini(void) 355 { 356 int i; 357 358 for (i = 0; i < RUMPBLK_SIZE; i++) { 359 struct rblkdev *rblk; 360 361 rblk = &minors[i]; 362 if (rblk->rblk_fd != -1) 363 backend_close(rblk); 364 } 365 } 366 367 static int 368 backend_open(struct rblkdev *rblk, const char *path) 369 { 370 int error, fd; 371 372 KASSERT(rblk->rblk_fd == -1); 373 error = rumpuser_open(path, 374 RUMPUSER_OPEN_RDWR | RUMPUSER_OPEN_BIO, &fd); 375 if (error) { 376 error = rumpuser_open(path, 377 RUMPUSER_OPEN_RDONLY | RUMPUSER_OPEN_BIO, &fd); 378 if (error) 379 return error; 380 rblk->rblk_mode = FREAD; 381 } else { 382 rblk->rblk_mode = FREAD|FWRITE; 383 } 384 385 rblk->rblk_fd = fd; 386 KASSERT(rblk->rblk_fd != -1); 387 return 0; 388 } 389 390 static int 391 backend_close(struct rblkdev *rblk) 392 { 393 394 rumpuser_close(rblk->rblk_fd); 395 rblk->rblk_fd = -1; 396 397 return 0; 398 } 399 400 int 401 rumpblk_open(dev_t dev, int flag, int fmt, struct lwp *l) 402 { 403 struct rblkdev *rblk = &minors[minor(dev)]; 404 405 if (rblk->rblk_fd == -1) 406 return ENXIO; 407 408 if (((flag & (FREAD|FWRITE)) & ~rblk->rblk_mode) != 0) { 409 return EACCES; 410 } 411 412 return 0; 413 } 414 415 int 416 rumpblk_close(dev_t dev, int flag, int fmt, struct lwp *l) 417 { 418 419 return 0; 420 } 421 422 int 423 rumpblk_ioctl(dev_t dev, u_long xfer, void *addr, int flag, struct lwp *l) 424 { 425 devminor_t dmin = minor(dev); 426 struct rblkdev *rblk = &minors[dmin]; 427 struct partinfo *pi; 428 struct partition *dp; 429 int error = 0; 430 431 /* well, me should support a few more, but we don't for now */ 432 switch (xfer) { 433 case DIOCGDINFO: 434 *(struct disklabel *)addr = rblk->rblk_label; 435 break; 436 437 case DIOCGPARTINFO: 438 dp = &rblk->rblk_label.d_partitions[DISKPART(dmin)]; 439 pi = addr; 440 pi->pi_offset = dp->p_offset; 441 pi->pi_size = dp->p_size; 442 pi->pi_secsize = rblk->rblk_label.d_secsize; 443 pi->pi_bsize = BLKDEV_IOSIZE; 444 pi->pi_fstype = dp->p_fstype; 445 pi->pi_fsize = dp->p_fsize; 446 pi->pi_frag = dp->p_frag; 447 pi->pi_cpg = dp->p_cpg; 448 break; 449 450 /* it's synced enough along the write path */ 451 case DIOCCACHESYNC: 452 break; 453 454 case DIOCGMEDIASIZE: 455 *(off_t *)addr = (off_t)rblk->rblk_size; 456 break; 457 458 default: 459 error = ENOTTY; 460 break; 461 } 462 463 return error; 464 } 465 466 static int 467 do_physio(dev_t dev, struct uio *uio, int which) 468 { 469 void (*strat)(struct buf *); 470 471 if (blkfail) 472 strat = rumpblk_strategy_fail; 473 else 474 strat = rumpblk_strategy; 475 476 return physio(strat, NULL, dev, which, minphys, uio); 477 } 478 479 int 480 rumpblk_read(dev_t dev, struct uio *uio, int flags) 481 { 482 483 return do_physio(dev, uio, B_READ); 484 } 485 486 int 487 rumpblk_write(dev_t dev, struct uio *uio, int flags) 488 { 489 490 return do_physio(dev, uio, B_WRITE); 491 } 492 493 static void 494 dostrategy(struct buf *bp) 495 { 496 struct rblkdev *rblk = &minors[minor(bp->b_dev)]; 497 off_t off; 498 int async = bp->b_flags & B_ASYNC; 499 int op; 500 501 if (bp->b_bcount % (1<<sectshift) != 0) { 502 rump_biodone(bp, 0, EINVAL); 503 return; 504 } 505 506 /* collect statistics */ 507 ev_io_total.ev_count++; 508 if (async) 509 ev_io_async.ev_count++; 510 if (BUF_ISWRITE(bp)) { 511 ev_bwrite_total.ev_count += bp->b_bcount; 512 if (async) 513 ev_bwrite_async.ev_count += bp->b_bcount; 514 } else { 515 ev_bread_total.ev_count++; 516 } 517 518 /* 519 * b_blkno is always in terms of DEV_BSIZE, and since we need 520 * to translate to a byte offset for the host read, this 521 * calculation does not need sectshift. 522 */ 523 off = bp->b_blkno << DEV_BSHIFT; 524 525 /* 526 * Do bounds checking if we're working on a file. Otherwise 527 * invalid file systems might attempt to read beyond EOF. This 528 * is bad(tm) especially on mmapped images. This is essentially 529 * the kernel bounds_check() routines. 530 */ 531 if (off + bp->b_bcount > rblk->rblk_size) { 532 int64_t sz = rblk->rblk_size - off; 533 534 /* EOF */ 535 if (sz == 0) { 536 rump_biodone(bp, 0, 0); 537 return; 538 } 539 /* beyond EOF ==> error */ 540 if (sz < 0) { 541 rump_biodone(bp, 0, EINVAL); 542 return; 543 } 544 545 /* truncate to device size */ 546 bp->b_bcount = sz; 547 } 548 549 off += rblk->rblk_hostoffset; 550 DPRINTF(("rumpblk_strategy: 0x%x bytes %s off 0x%" PRIx64 551 " (0x%" PRIx64 " - 0x%" PRIx64 "), %ssync\n", 552 bp->b_bcount, BUF_ISREAD(bp) ? "READ" : "WRITE", 553 off, off, (off + bp->b_bcount), async ? "a" : "")); 554 555 op = BUF_ISREAD(bp) ? RUMPUSER_BIO_READ : RUMPUSER_BIO_WRITE; 556 if (BUF_ISWRITE(bp) && !async) 557 op |= RUMPUSER_BIO_SYNC; 558 559 rumpuser_bio(rblk->rblk_fd, op, bp->b_data, bp->b_bcount, off, 560 rump_biodone, bp); 561 } 562 563 void 564 rumpblk_strategy(struct buf *bp) 565 { 566 567 dostrategy(bp); 568 } 569 570 /* 571 * Simple random number generator. This is private so that we can 572 * very repeatedly control which blocks will fail. 573 * 574 * <mlelstv> pooka, rand() 575 * <mlelstv> [paste] 576 */ 577 static unsigned 578 gimmerand(void) 579 { 580 581 return (randstate = randstate * 1103515245 + 12345) % (0x80000000L); 582 } 583 584 /* 585 * Block device with very simple fault injection. Fails every 586 * n out of BLKFAIL_MAX I/O with EIO. n is determined by the env 587 * variable RUMP_BLKFAIL. 588 */ 589 void 590 rumpblk_strategy_fail(struct buf *bp) 591 { 592 593 if (gimmerand() % BLKFAIL_MAX >= blkfail) { 594 dostrategy(bp); 595 } else { 596 printf("block fault injection: failing I/O on block %lld\n", 597 (long long)bp->b_blkno); 598 bp->b_error = EIO; 599 biodone(bp); 600 } 601 } 602
Indexes created Thu Oct 02 14:10:14 GMT 2025