1 /* $NetBSD: device-mapper.c,v 1.22 2010/03/26 15:46:04 jakllsch Exp $ */ 2 3 /* 4 * Copyright (c) 2010 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Adam Hamsik. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * I want to say thank you to all people who helped me with this project. 34 */ 35 36 #include <sys/types.h> 37 #include <sys/param.h> 38 39 #include <sys/buf.h> 40 #include <sys/conf.h> 41 #include <sys/device.h> 42 #include <sys/devfs.h> 43 #include <sys/disk.h> 44 #include <sys/disklabel.h> 45 #include <sys/dtype.h> 46 #include <sys/ioccom.h> 47 #include <sys/malloc.h> 48 #include <sys/module.h> 49 #include <sys/sysctl.h> 50 51 #include "netbsd-dm.h" 52 #include "dm.h" 53 54 static d_ioctl_t dmioctl; 55 static d_open_t dmopen; 56 static d_close_t dmclose; 57 static d_psize_t dmsize; 58 static d_strategy_t dmstrategy; 59 static d_dump_t dmdump; 60 61 /* attach and detach routines */ 62 void dmattach(int); 63 static int dm_modcmd(module_t mod, int cmd, void *unused); 64 static int dmdestroy(void); 65 66 static void dm_doinit(void); 67 68 static int dm_cmd_to_fun(prop_dictionary_t); 69 static int disk_ioctl_switch(cdev_t, u_long, void *); 70 static int dm_ioctl_switch(u_long); 71 #if 0 72 static void dmminphys(struct buf *); 73 #endif 74 75 struct devfs_bitmap dm_minor_bitmap; 76 77 /* ***Variable-definitions*** */ 78 struct dev_ops dm_ops = { 79 { "dm", 0, D_DISK | D_MPSAFE }, 80 .d_open = dmopen, 81 .d_close = dmclose, 82 .d_read = physread, 83 .d_write = physwrite, 84 .d_ioctl = dmioctl, 85 .d_strategy = dmstrategy, 86 .d_psize = dmsize, 87 .d_dump = dmdump, 88 /* D_DISK */ 89 }; 90 91 MALLOC_DEFINE(M_DM, "dm", "Device Mapper allocations"); 92 93 int dm_debug_level = 0; 94 95 extern uint64_t dm_dev_counter; 96 97 static cdev_t dmcdev; 98 99 static moduledata_t dm_mod = { 100 "dm", 101 dm_modcmd, 102 NULL 103 }; 104 DECLARE_MODULE(dm, dm_mod, SI_SUB_RAID, SI_ORDER_ANY); 105 106 /* 107 * This array is used to translate cmd to function pointer. 108 * 109 * Interface between libdevmapper and lvm2tools uses different 110 * names for one IOCTL call because libdevmapper do another thing 111 * then. When I run "info" or "mknodes" libdevmapper will send same 112 * ioctl to kernel but will do another things in userspace. 113 * 114 */ 115 static struct cmd_function cmd_fn[] = { 116 { .cmd = "version", .fn = dm_get_version_ioctl}, 117 { .cmd = "targets", .fn = dm_list_versions_ioctl}, 118 { .cmd = "create", .fn = dm_dev_create_ioctl}, 119 { .cmd = "info", .fn = dm_dev_status_ioctl}, 120 { .cmd = "mknodes", .fn = dm_dev_status_ioctl}, 121 { .cmd = "names", .fn = dm_dev_list_ioctl}, 122 { .cmd = "suspend", .fn = dm_dev_suspend_ioctl}, 123 { .cmd = "remove", .fn = dm_dev_remove_ioctl}, 124 { .cmd = "rename", .fn = dm_dev_rename_ioctl}, 125 { .cmd = "resume", .fn = dm_dev_resume_ioctl}, 126 { .cmd = "clear", .fn = dm_table_clear_ioctl}, 127 { .cmd = "deps", .fn = dm_table_deps_ioctl}, 128 { .cmd = "reload", .fn = dm_table_load_ioctl}, 129 { .cmd = "status", .fn = dm_table_status_ioctl}, 130 { .cmd = "table", .fn = dm_table_status_ioctl}, 131 {NULL, NULL} 132 }; 133 134 /* New module handle routine */ 135 static int 136 dm_modcmd(module_t mod, int cmd, void *unused) 137 { 138 int error, bmajor, cmajor; 139 140 error = 0; 141 bmajor = -1; 142 cmajor = -1; 143 144 switch (cmd) { 145 case MOD_LOAD: 146 devfs_clone_bitmap_init(&dm_minor_bitmap); 147 dm_doinit(); 148 kprintf("Device Mapper version %d.%d.%d loaded\n", 149 DM_VERSION_MAJOR, DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL); 150 break; 151 152 case MOD_UNLOAD: 153 /* 154 * Disable unloading of dm module if there are any devices 155 * defined in driver. This is probably too strong we need 156 * to disable auto-unload only if there is mounted dm device 157 * present. 158 */ 159 if (dm_dev_counter > 0) 160 return EBUSY; 161 162 error = dmdestroy(); 163 if (error) 164 break; 165 kprintf("Device Mapper unloaded\n"); 166 break; 167 168 default: 169 break; 170 } 171 172 return error; 173 } 174 175 /* 176 * dm_detach: 177 * 178 * Autoconfiguration detach function for pseudo-device glue. 179 * This routine is called by dm_ioctl::dm_dev_remove_ioctl and by autoconf to 180 * remove devices created in device-mapper. 181 */ 182 int 183 dm_detach(dm_dev_t *dmv) 184 { 185 int minor; 186 187 disable_dev(dmv); 188 189 /* Destroy active table first. */ 190 dm_table_destroy(&dmv->table_head, DM_TABLE_ACTIVE); 191 192 /* Destroy inactive table if exits, too. */ 193 dm_table_destroy(&dmv->table_head, DM_TABLE_INACTIVE); 194 195 dm_table_head_destroy(&dmv->table_head); 196 197 minor = dkunit(dmv->devt); 198 disk_destroy(dmv->diskp); 199 devstat_remove_entry(&dmv->stats); 200 201 release_dev(dmv->devt); 202 devfs_clone_bitmap_put(&dm_minor_bitmap, minor); 203 204 /* Destroy device */ 205 (void)dm_dev_free(dmv); 206 207 /* Decrement device counter After removing device */ 208 --dm_dev_counter; /* XXX: was atomic 64 */ 209 210 return 0; 211 } 212 213 static void 214 dm_doinit(void) 215 { 216 dm_target_init(); 217 dm_dev_init(); 218 dm_pdev_init(); 219 dmcdev = make_dev(&dm_ops, 0, UID_ROOT, GID_OPERATOR, 0640, "mapper/control"); 220 } 221 222 /* Destroy routine */ 223 static int 224 dmdestroy(void) 225 { 226 destroy_dev(dmcdev); 227 228 dm_dev_destroy(); 229 dm_pdev_destroy(); 230 dm_target_destroy(); 231 232 return 0; 233 } 234 235 static int 236 dmopen(struct dev_open_args *ap) 237 { 238 cdev_t dev = ap->a_head.a_dev; 239 dm_dev_t *dmv; 240 241 /* Shortcut for the control device */ 242 if (minor(dev) == 0) 243 return 0; 244 245 if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL) 246 return ENXIO; 247 248 dmv->is_open = 1; 249 dm_dev_unbusy(dmv); 250 251 aprint_debug("dm open routine called %" PRIu32 "\n", 252 minor(ap->a_head.a_dev)); 253 return 0; 254 } 255 256 static int 257 dmclose(struct dev_close_args *ap) 258 { 259 cdev_t dev = ap->a_head.a_dev; 260 dm_dev_t *dmv; 261 262 /* Shortcut for the control device */ 263 if (minor(dev) == 0) 264 return 0; 265 266 if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL) 267 return ENXIO; 268 269 dmv->is_open = 0; 270 dm_dev_unbusy(dmv); 271 272 aprint_debug("dm close routine called %" PRIu32 "\n", 273 minor(ap->a_head.a_dev)); 274 return 0; 275 } 276 277 278 static int 279 dmioctl(struct dev_ioctl_args *ap) 280 { 281 cdev_t dev = ap->a_head.a_dev; 282 u_long cmd = ap->a_cmd; 283 void *data = ap->a_data; 284 285 int r, err; 286 prop_dictionary_t dm_dict_in; 287 288 err = r = 0; 289 290 aprint_debug("dmioctl called\n"); 291 292 KKASSERT(data != NULL); 293 294 if (( r = disk_ioctl_switch(dev, cmd, data)) == ENOTTY) { 295 struct plistref *pref = (struct plistref *) data; 296 297 /* Check if we were called with NETBSD_DM_IOCTL ioctl 298 otherwise quit. */ 299 if ((r = dm_ioctl_switch(cmd)) != 0) 300 return r; 301 302 if((r = prop_dictionary_copyin_ioctl(pref, cmd, &dm_dict_in)) != 0) 303 return r; 304 305 if ((r = dm_check_version(dm_dict_in)) != 0) 306 goto cleanup_exit; 307 308 /* run ioctl routine */ 309 if ((err = dm_cmd_to_fun(dm_dict_in)) != 0) 310 goto cleanup_exit; 311 312 cleanup_exit: 313 r = prop_dictionary_copyout_ioctl(pref, cmd, dm_dict_in); 314 prop_object_release(dm_dict_in); 315 } 316 317 /* 318 * Return the error of the actual command if one one has 319 * happened. Otherwise return 'r' which indicates errors 320 * that occurred during helper operations. 321 */ 322 return (err != 0)?err:r; 323 } 324 325 /* 326 * Translate command sent from libdevmapper to func. 327 */ 328 static int 329 dm_cmd_to_fun(prop_dictionary_t dm_dict){ 330 int i, r; 331 prop_string_t command; 332 333 r = 0; 334 335 if ((command = prop_dictionary_get(dm_dict, DM_IOCTL_COMMAND)) == NULL) 336 return EINVAL; 337 338 for(i = 0; cmd_fn[i].cmd != NULL; i++) 339 if (prop_string_equals_cstring(command, cmd_fn[i].cmd)) 340 break; 341 342 if (cmd_fn[i].cmd == NULL) 343 return EINVAL; 344 345 aprint_debug("ioctl %s called\n", cmd_fn[i].cmd); 346 r = cmd_fn[i].fn(dm_dict); 347 348 return r; 349 } 350 351 /* Call apropriate ioctl handler function. */ 352 static int 353 dm_ioctl_switch(u_long cmd) 354 { 355 356 switch(cmd) { 357 358 case NETBSD_DM_IOCTL: 359 aprint_debug("dm NetBSD_DM_IOCTL called\n"); 360 break; 361 default: 362 aprint_debug("dm unknown ioctl called\n"); 363 return ENOTTY; 364 break; /* NOT REACHED */ 365 } 366 367 return 0; 368 } 369 370 /* 371 * Check for disk specific ioctls. 372 */ 373 374 static int 375 disk_ioctl_switch(cdev_t dev, u_long cmd, void *data) 376 { 377 dm_dev_t *dmv; 378 379 /* disk ioctls make sense only on block devices */ 380 if (minor(dev) == 0) 381 return ENOTTY; 382 383 switch(cmd) { 384 case DIOCGPART: 385 { 386 struct partinfo *dpart; 387 u_int64_t size; 388 dpart = (void *)data; 389 bzero(dpart, sizeof(*dpart)); 390 391 if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL) 392 return ENODEV; 393 if (dmv->diskp->d_info.d_media_blksize == 0) { 394 dm_dev_unbusy(dmv); 395 return ENOTSUP; 396 } else { 397 size = dm_table_size(&dmv->table_head); 398 dpart->media_offset = 0; 399 dpart->media_size = size * DEV_BSIZE; 400 dpart->media_blocks = size; 401 dpart->media_blksize = DEV_BSIZE; 402 dpart->fstype = FS_BSDFFS; 403 } 404 dm_dev_unbusy(dmv); 405 break; 406 } 407 408 default: 409 aprint_debug("unknown disk_ioctl called\n"); 410 return ENOTTY; 411 break; /* NOT REACHED */ 412 } 413 414 return 0; 415 } 416 417 /* 418 * Do all IO operations on dm logical devices. 419 */ 420 static int 421 dmstrategy(struct dev_strategy_args *ap) 422 { 423 cdev_t dev = ap->a_head.a_dev; 424 struct bio *bio = ap->a_bio; 425 struct buf *bp = bio->bio_buf; 426 int bypass; 427 428 dm_dev_t *dmv; 429 dm_table_t *tbl; 430 dm_table_entry_t *table_en; 431 struct buf *nestbuf; 432 433 uint32_t dev_type; 434 435 uint64_t buf_start, buf_len, issued_len; 436 uint64_t table_start, table_end; 437 uint64_t start, end; 438 439 buf_start = bio->bio_offset; 440 buf_len = bp->b_bcount; 441 442 tbl = NULL; 443 444 table_end = 0; 445 dev_type = 0; 446 issued_len = 0; 447 448 if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL) { 449 bp->b_error = EIO; 450 bp->b_resid = bp->b_bcount; 451 biodone(bio); 452 return 0; 453 } 454 455 switch(bp->b_cmd) { 456 case BUF_CMD_READ: 457 case BUF_CMD_WRITE: 458 case BUF_CMD_FREEBLKS: 459 bypass = 0; 460 break; 461 case BUF_CMD_FLUSH: 462 bypass = 1; 463 KKASSERT(buf_len == 0); 464 break; 465 default: 466 dm_dev_unbusy(dmv); 467 bp->b_error = EIO; 468 bp->b_resid = bp->b_bcount; 469 biodone(bio); 470 return 0; 471 } 472 473 if (bypass == 0 && 474 bounds_check_with_mediasize(bio, DEV_BSIZE, 475 dm_table_size(&dmv->table_head)) <= 0) { 476 dm_dev_unbusy(dmv); 477 bp->b_resid = bp->b_bcount; 478 biodone(bio); 479 return 0; 480 } 481 482 /* Select active table */ 483 tbl = dm_table_get_entry(&dmv->table_head, DM_TABLE_ACTIVE); 484 485 nestiobuf_init(bio); 486 devstat_start_transaction(&dmv->stats); 487 488 /* 489 * Find out what tables I want to select. 490 */ 491 SLIST_FOREACH(table_en, tbl, next) { 492 /* 493 * I need need number of bytes not blocks. 494 */ 495 table_start = table_en->start * DEV_BSIZE; 496 table_end = table_start + (table_en->length) * DEV_BSIZE; 497 498 /* 499 * Calculate the start and end 500 */ 501 start = MAX(table_start, buf_start); 502 end = MIN(table_end, buf_start + buf_len); 503 504 aprint_debug("----------------------------------------\n"); 505 aprint_debug("table_start %010" PRIu64", table_end %010" 506 PRIu64 "\n", table_start, table_end); 507 aprint_debug("buf_start %010" PRIu64", buf_len %010" 508 PRIu64"\n", buf_start, buf_len); 509 aprint_debug("start-buf_start %010"PRIu64", end %010" 510 PRIu64"\n", start - buf_start, end); 511 aprint_debug("start %010" PRIu64" , end %010" 512 PRIu64"\n", start, end); 513 aprint_debug("\n----------------------------------------\n"); 514 515 if (bypass) { 516 nestbuf = getpbuf(NULL); 517 nestbuf->b_flags |= bio->bio_buf->b_flags & B_HASBOGUS; 518 519 nestiobuf_add(bio, nestbuf, 0, 0, &dmv->stats); 520 nestbuf->b_bio1.bio_offset = 0; 521 table_en->target->strategy(table_en, nestbuf); 522 } else if (start < end) { 523 nestbuf = getpbuf(NULL); 524 nestbuf->b_flags |= bio->bio_buf->b_flags & B_HASBOGUS; 525 526 nestiobuf_add(bio, nestbuf, 527 start - buf_start, (end - start), 528 &dmv->stats); 529 issued_len += end - start; 530 531 nestbuf->b_bio1.bio_offset = (start - table_start); 532 table_en->target->strategy(table_en, nestbuf); 533 } 534 } 535 536 if (issued_len < buf_len) 537 nestiobuf_error(bio, EINVAL); 538 nestiobuf_start(bio); 539 dm_table_release(&dmv->table_head, DM_TABLE_ACTIVE); 540 dm_dev_unbusy(dmv); 541 542 return 0; 543 } 544 545 static int 546 dmdump(struct dev_dump_args *ap) 547 { 548 cdev_t dev = ap->a_head.a_dev; 549 dm_dev_t *dmv; 550 dm_table_t *tbl; 551 dm_table_entry_t *table_en; 552 uint32_t dev_type; 553 uint64_t buf_start, buf_len, issued_len; 554 uint64_t table_start, table_end; 555 uint64_t start, end, data_offset; 556 off_t offset; 557 size_t length; 558 int error = 0; 559 560 buf_start = ap->a_offset; 561 buf_len = ap->a_length; 562 563 tbl = NULL; 564 565 table_end = 0; 566 dev_type = 0; 567 issued_len = 0; 568 569 if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL) { 570 return EIO; 571 } 572 573 /* Select active table */ 574 tbl = dm_table_get_entry(&dmv->table_head, DM_TABLE_ACTIVE); 575 576 577 /* 578 * Find out what tables I want to select. 579 */ 580 SLIST_FOREACH(table_en, tbl, next) { 581 /* 582 * I need need number of bytes not blocks. 583 */ 584 table_start = table_en->start * DEV_BSIZE; 585 table_end = table_start + (table_en->length) * DEV_BSIZE; 586 587 /* 588 * Calculate the start and end 589 */ 590 start = MAX(table_start, buf_start); 591 end = MIN(table_end, buf_start + buf_len); 592 593 if (ap->a_length == 0) { 594 if (table_en->target->dump == NULL) { 595 error = ENXIO; 596 goto out; 597 } 598 599 table_en->target->dump(table_en, NULL, 0, 0); 600 } else if (start < end) { 601 data_offset = start - buf_start; 602 offset = start - table_start; 603 length = end - start; 604 605 if (table_en->target->dump == NULL) { 606 error = ENXIO; 607 goto out; 608 } 609 610 table_en->target->dump(table_en, 611 (char *)ap->a_virtual + data_offset, 612 length, offset); 613 614 issued_len += end - start; 615 } 616 } 617 618 if (issued_len < buf_len) 619 error = EINVAL; 620 621 out: 622 dm_table_release(&dmv->table_head, DM_TABLE_ACTIVE); 623 dm_dev_unbusy(dmv); 624 625 return error; 626 } 627 628 static int 629 dmsize(struct dev_psize_args *ap) 630 { 631 cdev_t dev = ap->a_head.a_dev; 632 dm_dev_t *dmv; 633 uint64_t size; 634 635 size = 0; 636 637 if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL) 638 return ENOENT; 639 640 size = dm_table_size(&dmv->table_head); 641 dm_dev_unbusy(dmv); 642 643 ap->a_result = (int64_t)size; 644 645 return 0; 646 } 647 648 #if 0 649 static void 650 dmminphys(struct buf *bp) 651 { 652 653 bp->b_bcount = MIN(bp->b_bcount, MAXPHYS); 654 } 655 #endif 656 657 void 658 dmsetdiskinfo(struct disk *disk, dm_table_head_t *head) 659 { 660 struct disk_info info; 661 uint64_t dmp_size; 662 663 dmp_size = dm_table_size(head); 664 665 bzero(&info, sizeof(struct disk_info)); 666 info.d_media_blksize = DEV_BSIZE; 667 info.d_media_blocks = dmp_size; 668 #if 0 669 /* this is set by disk_setdiskinfo */ 670 info.d_media_size = dmp_size * DEV_BSIZE; 671 #endif 672 info.d_dsflags = DSO_MBRQUIET | DSO_DEVICEMAPPER; 673 674 info.d_secpertrack = 32; 675 info.d_nheads = 64; 676 info.d_secpercyl = info.d_secpertrack * info.d_nheads; 677 info.d_ncylinders = dmp_size / info.d_secpercyl; 678 679 disk_setdiskinfo(disk, &info); 680 } 681 682 prop_dictionary_t 683 dmgetdiskinfo(struct disk *disk) 684 { 685 prop_dictionary_t disk_info, geom; 686 struct disk_info *pinfo; 687 688 pinfo = &disk->d_info; 689 690 disk_info = prop_dictionary_create(); 691 geom = prop_dictionary_create(); 692 693 prop_dictionary_set_cstring_nocopy(disk_info, "type", "ESDI"); 694 prop_dictionary_set_uint64(geom, "sectors-per-unit", pinfo->d_media_blocks); 695 prop_dictionary_set_uint32(geom, "sector-size", 696 DEV_BSIZE /* XXX 512? */); 697 prop_dictionary_set_uint32(geom, "sectors-per-track", 32); 698 prop_dictionary_set_uint32(geom, "tracks-per-cylinder", 64); 699 prop_dictionary_set_uint32(geom, "cylinders-per-unit", 700 pinfo->d_media_blocks / 2048); 701 prop_dictionary_set(disk_info, "geometry", geom); 702 prop_object_release(geom); 703 704 return disk_info; 705 } 706 707 void 708 dmgetproperties(struct disk *disk, dm_table_head_t *head) 709 { 710 #if 0 711 prop_dictionary_t disk_info, odisk_info, geom; 712 int dmp_size; 713 714 dmp_size = dm_table_size(head); 715 disk_info = prop_dictionary_create(); 716 geom = prop_dictionary_create(); 717 718 prop_dictionary_set_cstring_nocopy(disk_info, "type", "ESDI"); 719 prop_dictionary_set_uint64(geom, "sectors-per-unit", dmp_size); 720 prop_dictionary_set_uint32(geom, "sector-size", 721 DEV_BSIZE /* XXX 512? */); 722 prop_dictionary_set_uint32(geom, "sectors-per-track", 32); 723 prop_dictionary_set_uint32(geom, "tracks-per-cylinder", 64); 724 prop_dictionary_set_uint32(geom, "cylinders-per-unit", dmp_size / 2048); 725 prop_dictionary_set(disk_info, "geometry", geom); 726 prop_object_release(geom); 727 728 odisk_info = disk->dk_info; 729 disk->dk_info = disk_info; 730 731 if (odisk_info != NULL) 732 prop_object_release(odisk_info); 733 #endif 734 } 735 736 TUNABLE_INT("debug.dm_debug", &dm_debug_level); 737 SYSCTL_INT(_debug, OID_AUTO, dm_debug, CTLFLAG_RW, &dm_debug_level, 738 0, "Eanble device mapper debugging"); 739 740