drivers/md/dm-ioctl.c

   1 /*
   2  * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
   3  * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #include "dm.h"
   9
  10 #include <linux/module.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/miscdevice.h>
  13 #include <linux/init.h>
  14 #include <linux/wait.h>
  15 #include <linux/slab.h>
  16 #include <linux/dm-ioctl.h>
  17 #include <linux/hdreg.h>
  18 #include <linux/compat.h>
  19
  20 #include <asm/uaccess.h>
  21
  22 #define DM_MSG_PREFIX "ioctl"
  23 #define DM_DRIVER_EMAIL "dm-devel@redhat.com"
  24
  25 /*-----------------------------------------------------------------
  26  * The ioctl interface needs to be able to look up devices by
  27  * name or uuid.
  28  *---------------------------------------------------------------*/
  29 struct hash_cell {
  30         struct list_head name_list;
  31         struct list_head uuid_list;
  32
  33         char *name;
  34         char *uuid;
  35         struct mapped_device *md;
  36         struct dm_table *new_map;
  37 };
  38
  39 struct vers_iter {
  40     size_t param_size;
  41     struct dm_target_versions *vers, *old_vers;
  42     char *end;
  43     uint32_t flags;
  44 };
  45
  46
  47 #define NUM_BUCKETS 64
  48 #define MASK_BUCKETS (NUM_BUCKETS - 1)
  49 static struct list_head _name_buckets[NUM_BUCKETS];
  50 static struct list_head _uuid_buckets[NUM_BUCKETS];
  51
  52 static void dm_hash_remove_all(int keep_open_devices);
  53
  54 /*
  55  * Guards access to both hash tables.
  56  */
  57 static DECLARE_RWSEM(_hash_lock);
  58
  59 static void init_buckets(struct list_head *buckets)
  60 {
  61         unsigned int i;
  62
  63         for (i = 0; i < NUM_BUCKETS; i++)
  64                 INIT_LIST_HEAD(buckets + i);
  65 }
  66
  67 static int dm_hash_init(void)
  68 {
  69         init_buckets(_name_buckets);
  70         init_buckets(_uuid_buckets);
  71         return 0;
  72 }
  73
  74 static void dm_hash_exit(void)
  75 {
  76         dm_hash_remove_all(0);
  77 }
  78
  79 /*-----------------------------------------------------------------
  80  * Hash function:
  81  * We're not really concerned with the str hash function being
  82  * fast since it's only used by the ioctl interface.
  83  *---------------------------------------------------------------*/
  84 static unsigned int hash_str(const char *str)
  85 {
  86         const unsigned int hash_mult = 2654435387U;
  87         unsigned int h = 0;
  88
  89         while (*str)
  90                 h = (h + (unsigned int) *str++) * hash_mult;
  91
  92         return h & MASK_BUCKETS;
  93 }
  94
  95 /*-----------------------------------------------------------------
  96  * Code for looking up a device by name
  97  *---------------------------------------------------------------*/
  98 static struct hash_cell *__get_name_cell(const char *str)
  99 {
 100         struct hash_cell *hc;
 101         unsigned int h = hash_str(str);
 102
 103         list_for_each_entry (hc, _name_buckets + h, name_list)
 104                 if (!strcmp(hc->name, str)) {
 105                         dm_get(hc->md);
 106                         return hc;
 107                 }
 108
 109         return NULL;
 110 }
 111
 112 static struct hash_cell *__get_uuid_cell(const char *str)
 113 {
 114         struct hash_cell *hc;
 115         unsigned int h = hash_str(str);
 116
 117         list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
 118                 if (!strcmp(hc->uuid, str)) {
 119                         dm_get(hc->md);
 120                         return hc;
 121                 }
 122
 123         return NULL;
 124 }
 125
 126 /*-----------------------------------------------------------------
 127  * Inserting, removing and renaming a device.
 128  *---------------------------------------------------------------*/
 129 static struct hash_cell *alloc_cell(const char *name, const char *uuid,
 130                                     struct mapped_device *md)
 131 {
 132         struct hash_cell *hc;
 133
 134         hc = kmalloc(sizeof(*hc), GFP_KERNEL);
 135         if (!hc)
 136                 return NULL;
 137
 138         hc->name = kstrdup(name, GFP_KERNEL);
 139         if (!hc->name) {
 140                 kfree(hc);
 141                 return NULL;
 142         }
 143
 144         if (!uuid)
 145                 hc->uuid = NULL;
 146
 147         else {
 148                 hc->uuid = kstrdup(uuid, GFP_KERNEL);
 149                 if (!hc->uuid) {
 150                         kfree(hc->name);
 151                         kfree(hc);
 152                         return NULL;
 153                 }
 154         }
 155
 156         INIT_LIST_HEAD(&hc->name_list);
 157         INIT_LIST_HEAD(&hc->uuid_list);
 158         hc->md = md;
 159         hc->new_map = NULL;
 160         return hc;
 161 }
 162
 163 static void free_cell(struct hash_cell *hc)
 164 {
 165         if (hc) {
 166                 kfree(hc->name);
 167                 kfree(hc->uuid);
 168                 kfree(hc);
 169         }
 170 }
 171
 172 /*
 173  * The kdev_t and uuid of a device can never change once it is
 174  * initially inserted.
 175  */
 176 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
 177 {
 178         struct hash_cell *cell, *hc;
 179
 180         /*
 181          * Allocate the new cells.
 182          */
 183         cell = alloc_cell(name, uuid, md);
 184         if (!cell)
 185                 return -ENOMEM;
 186
 187         /*
 188          * Insert the cell into both hash tables.
 189          */
 190         down_write(&_hash_lock);
 191         hc = __get_name_cell(name);
 192         if (hc) {
 193                 dm_put(hc->md);
 194                 goto bad;
 195         }
 196
 197         list_add(&cell->name_list, _name_buckets + hash_str(name));
 198
 199         if (uuid) {
 200                 hc = __get_uuid_cell(uuid);
 201                 if (hc) {
 202                         list_del(&cell->name_list);
 203                         dm_put(hc->md);
 204                         goto bad;
 205                 }
 206                 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
 207         }
 208         dm_get(md);
 209         dm_set_mdptr(md, cell);
 210         up_write(&_hash_lock);
 211
 212         return 0;
 213
 214  bad:
 215         up_write(&_hash_lock);
 216         free_cell(cell);
 217         return -EBUSY;
 218 }
 219
 220 static void __hash_remove(struct hash_cell *hc)
 221 {
 222         struct dm_table *table;
 223
 224         /* remove from the dev hash */
 225         list_del(&hc->uuid_list);
 226         list_del(&hc->name_list);
 227         dm_set_mdptr(hc->md, NULL);
 228
 229         table = dm_get_table(hc->md);
 230         if (table) {
 231                 dm_table_event(table);
 232                 dm_table_put(table);
 233         }
 234
 235         if (hc->new_map)
 236                 dm_table_put(hc->new_map);
 237         dm_put(hc->md);
 238         free_cell(hc);
 239 }
 240
 241 static void dm_hash_remove_all(int keep_open_devices)
 242 {
 243         int i, dev_skipped, dev_removed;
 244         struct hash_cell *hc;
 245         struct list_head *tmp, *n;
 246
 247         down_write(&_hash_lock);
 248
 249 retry:
 250         dev_skipped = dev_removed = 0;
 251         for (i = 0; i < NUM_BUCKETS; i++) {
 252                 list_for_each_safe (tmp, n, _name_buckets + i) {
 253                         hc = list_entry(tmp, struct hash_cell, name_list);
 254
 255                         if (keep_open_devices &&
 256                             dm_lock_for_deletion(hc->md)) {
 257                                 dev_skipped++;
 258                                 continue;
 259                         }
 260                         __hash_remove(hc);
 261                         dev_removed = 1;
 262                 }
 263         }
 264
 265         /*
 266          * Some mapped devices may be using other mapped devices, so if any
 267          * still exist, repeat until we make no further progress.
 268          */
 269         if (dev_skipped) {
 270                 if (dev_removed)
 271                         goto retry;
 272
 273                 DMWARN("remove_all left %d open device(s)", dev_skipped);
 274         }
 275
 276         up_write(&_hash_lock);
 277 }
 278
 279 static int dm_hash_rename(const char *old, const char *new)
 280 {
 281         char *new_name, *old_name;
 282         struct hash_cell *hc;
 283         struct dm_table *table;
 284
 285         /*
 286          * duplicate new.
 287          */
 288         new_name = kstrdup(new, GFP_KERNEL);
 289         if (!new_name)
 290                 return -ENOMEM;
 291
 292         down_write(&_hash_lock);
 293
 294         /*
 295          * Is new free ?
 296          */
 297         hc = __get_name_cell(new);
 298         if (hc) {
 299                 DMWARN("asked to rename to an already existing name %s -> %s",
 300                        old, new);
 301                 dm_put(hc->md);
 302                 up_write(&_hash_lock);
 303                 kfree(new_name);
 304                 return -EBUSY;
 305         }
 306
 307         /*
 308          * Is there such a device as 'old' ?
 309          */
 310         hc = __get_name_cell(old);
 311         if (!hc) {
 312                 DMWARN("asked to rename a non existent device %s -> %s",
 313                        old, new);
 314                 up_write(&_hash_lock);
 315                 kfree(new_name);
 316                 return -ENXIO;
 317         }
 318
 319         /*
 320          * rename and move the name cell.
 321          */
 322         list_del(&hc->name_list);
 323         old_name = hc->name;
 324         hc->name = new_name;
 325         list_add(&hc->name_list, _name_buckets + hash_str(new_name));
 326
 327         /*
 328          * Wake up any dm event waiters.
 329          */
 330         table = dm_get_table(hc->md);
 331         if (table) {
 332                 dm_table_event(table);
 333                 dm_table_put(table);
 334         }
 335
 336         dm_kobject_uevent(hc->md);
 337
 338         dm_put(hc->md);
 339         up_write(&_hash_lock);
 340         kfree(old_name);
 341         return 0;
 342 }
 343
 344 /*-----------------------------------------------------------------
 345  * Implementation of the ioctl commands
 346  *---------------------------------------------------------------*/
 347 /*
 348  * All the ioctl commands get dispatched to functions with this
 349  * prototype.
 350  */
 351 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
 352
 353 static int remove_all(struct dm_ioctl *param, size_t param_size)
 354 {
 355         dm_hash_remove_all(1);
 356         param->data_size = 0;
 357         return 0;
 358 }
 359
 360 /*
 361  * Round up the ptr to an 8-byte boundary.
 362  */
 363 #define ALIGN_MASK 7
 364 static inline void *align_ptr(void *ptr)
 365 {
 366         return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
 367 }
 368
 369 /*
 370  * Retrieves the data payload buffer from an already allocated
 371  * struct dm_ioctl.
 372  */
 373 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
 374                                size_t *len)
 375 {
 376         param->data_start = align_ptr(param + 1) - (void *) param;
 377
 378         if (param->data_start < param_size)
 379                 *len = param_size - param->data_start;
 380         else
 381                 *len = 0;
 382
 383         return ((void *) param) + param->data_start;
 384 }
 385
 386 static int list_devices(struct dm_ioctl *param, size_t param_size)
 387 {
 388         unsigned int i;
 389         struct hash_cell *hc;
 390         size_t len, needed = 0;
 391         struct gendisk *disk;
 392         struct dm_name_list *nl, *old_nl = NULL;
 393
 394         down_write(&_hash_lock);
 395
 396         /*
 397          * Loop through all the devices working out how much
 398          * space we need.
 399          */
 400         for (i = 0; i < NUM_BUCKETS; i++) {
 401                 list_for_each_entry (hc, _name_buckets + i, name_list) {
 402                         needed += sizeof(struct dm_name_list);
 403                         needed += strlen(hc->name) + 1;
 404                         needed += ALIGN_MASK;
 405                 }
 406         }
 407
 408         /*
 409          * Grab our output buffer.
 410          */
 411         nl = get_result_buffer(param, param_size, &len);
 412         if (len < needed) {
 413                 param->flags |= DM_BUFFER_FULL_FLAG;
 414                 goto out;
 415         }
 416         param->data_size = param->data_start + needed;
 417
 418         nl->dev = 0;    /* Flags no data */
 419
 420         /*
 421          * Now loop through filling out the names.
 422          */
 423         for (i = 0; i < NUM_BUCKETS; i++) {
 424                 list_for_each_entry (hc, _name_buckets + i, name_list) {
 425                         if (old_nl)
 426                                 old_nl->next = (uint32_t) ((void *) nl -
 427                                                            (void *) old_nl);
 428                         disk = dm_disk(hc->md);
 429                         nl->dev = huge_encode_dev(disk_devt(disk));
 430                         nl->next = 0;
 431                         strcpy(nl->name, hc->name);
 432
 433                         old_nl = nl;
 434                         nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
 435                 }
 436         }
 437
 438  out:
 439         up_write(&_hash_lock);
 440         return 0;
 441 }
 442
 443 static void list_version_get_needed(struct target_type *tt, void *needed_param)
 444 {
 445     size_t *needed = needed_param;
 446
 447     *needed += sizeof(struct dm_target_versions);
 448     *needed += strlen(tt->name);
 449     *needed += ALIGN_MASK;
 450 }
 451
 452 static void list_version_get_info(struct target_type *tt, void *param)
 453 {
 454     struct vers_iter *info = param;
 455
 456     /* Check space - it might have changed since the first iteration */
 457     if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
 458         info->end) {
 459
 460         info->flags = DM_BUFFER_FULL_FLAG;
 461         return;
 462     }
 463
 464     if (info->old_vers)
 465         info->old_vers->next = (uint32_t) ((void *)info->vers -
 466                                            (void *)info->old_vers);
 467     info->vers->version[0] = tt->version[0];
 468     info->vers->version[1] = tt->version[1];
 469     info->vers->version[2] = tt->version[2];
 470     info->vers->next = 0;
 471     strcpy(info->vers->name, tt->name);
 472
 473     info->old_vers = info->vers;
 474     info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
 475 }
 476
 477 static int list_versions(struct dm_ioctl *param, size_t param_size)
 478 {
 479         size_t len, needed = 0;
 480         struct dm_target_versions *vers;
 481         struct vers_iter iter_info;
 482
 483         /*
 484          * Loop through all the devices working out how much
 485          * space we need.
 486          */
 487         dm_target_iterate(list_version_get_needed, &needed);
 488
 489         /*
 490          * Grab our output buffer.
 491          */
 492         vers = get_result_buffer(param, param_size, &len);
 493         if (len < needed) {
 494                 param->flags |= DM_BUFFER_FULL_FLAG;
 495                 goto out;
 496         }
 497         param->data_size = param->data_start + needed;
 498
 499         iter_info.param_size = param_size;
 500         iter_info.old_vers = NULL;
 501         iter_info.vers = vers;
 502         iter_info.flags = 0;
 503         iter_info.end = (char *)vers+len;
 504
 505         /*
 506          * Now loop through filling out the names & versions.
 507          */
 508         dm_target_iterate(list_version_get_info, &iter_info);
 509         param->flags |= iter_info.flags;
 510
 511  out:
 512         return 0;
 513 }
 514
 515
 516
 517 static int check_name(const char *name)
 518 {
 519         if (strchr(name, '/')) {
 520                 DMWARN("invalid device name");
 521                 return -EINVAL;
 522         }
 523
 524         return 0;
 525 }
 526
 527 /*
 528  * Fills in a dm_ioctl structure, ready for sending back to
 529  * userland.
 530  */
 531 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 532 {
 533         struct gendisk *disk = dm_disk(md);
 534         struct dm_table *table;
 535
 536         param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
 537                           DM_ACTIVE_PRESENT_FLAG);
 538
 539         if (dm_suspended(md))
 540                 param->flags |= DM_SUSPEND_FLAG;
 541
 542         param->dev = huge_encode_dev(disk_devt(disk));
 543
 544         /*
 545          * Yes, this will be out of date by the time it gets back
 546          * to userland, but it is still very useful for
 547          * debugging.
 548          */
 549         param->open_count = dm_open_count(md);
 550
 551         if (get_disk_ro(disk))
 552                 param->flags |= DM_READONLY_FLAG;
 553
 554         param->event_nr = dm_get_event_nr(md);
 555
 556         table = dm_get_table(md);
 557         if (table) {
 558                 param->flags |= DM_ACTIVE_PRESENT_FLAG;
 559                 param->target_count = dm_table_get_num_targets(table);
 560                 dm_table_put(table);
 561         } else
 562                 param->target_count = 0;
 563
 564         return 0;
 565 }
 566
 567 static int dev_create(struct dm_ioctl *param, size_t param_size)
 568 {
 569         int r, m = DM_ANY_MINOR;
 570         struct mapped_device *md;
 571
 572         r = check_name(param->name);
 573         if (r)
 574                 return r;
 575
 576         if (param->flags & DM_PERSISTENT_DEV_FLAG)
 577                 m = MINOR(huge_decode_dev(param->dev));
 578
 579         r = dm_create(m, &md);
 580         if (r)
 581                 return r;
 582
 583         r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
 584         if (r) {
 585                 dm_put(md);
 586                 return r;
 587         }
 588
 589         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 590
 591         r = __dev_status(md, param);
 592         dm_put(md);
 593
 594         return r;
 595 }
 596
 597 /*
 598  * Always use UUID for lookups if it's present, otherwise use name or dev.
 599  */
 600 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
 601 {
 602         struct mapped_device *md;
 603         void *mdptr = NULL;
 604
 605         if (*param->uuid)
 606                 return __get_uuid_cell(param->uuid);
 607
 608         if (*param->name)
 609                 return __get_name_cell(param->name);
 610
 611         md = dm_get_md(huge_decode_dev(param->dev));
 612         if (!md)
 613                 goto out;
 614
 615         mdptr = dm_get_mdptr(md);
 616         if (!mdptr)
 617                 dm_put(md);
 618
 619 out:
 620         return mdptr;
 621 }
 622
 623 static struct mapped_device *find_device(struct dm_ioctl *param)
 624 {
 625         struct hash_cell *hc;
 626         struct mapped_device *md = NULL;
 627
 628         down_read(&_hash_lock);
 629         hc = __find_device_hash_cell(param);
 630         if (hc) {
 631                 md = hc->md;
 632
 633                 /*
 634                  * Sneakily write in both the name and the uuid
 635                  * while we have the cell.
 636                  */
 637                 strncpy(param->name, hc->name, sizeof(param->name));
 638                 if (hc->uuid)
 639                         strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
 640                 else
 641                         param->uuid[0] = '\0';
 642
 643                 if (hc->new_map)
 644                         param->flags |= DM_INACTIVE_PRESENT_FLAG;
 645                 else
 646                         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 647         }
 648         up_read(&_hash_lock);
 649
 650         return md;
 651 }
 652
 653 static int dev_remove(struct dm_ioctl *param, size_t param_size)
 654 {
 655         struct hash_cell *hc;
 656         struct mapped_device *md;
 657         int r;
 658
 659         down_write(&_hash_lock);
 660         hc = __find_device_hash_cell(param);
 661
 662         if (!hc) {
 663                 DMWARN("device doesn't appear to be in the dev hash table.");
 664                 up_write(&_hash_lock);
 665                 return -ENXIO;
 666         }
 667
 668         md = hc->md;
 669
 670         /*
 671          * Ensure the device is not open and nothing further can open it.
 672          */
 673         r = dm_lock_for_deletion(md);
 674         if (r) {
 675                 DMWARN("unable to remove open device %s", hc->name);
 676                 up_write(&_hash_lock);
 677                 dm_put(md);
 678                 return r;
 679         }
 680
 681         __hash_remove(hc);
 682         up_write(&_hash_lock);
 683         dm_put(md);
 684         param->data_size = 0;
 685         return 0;
 686 }
 687
 688 /*
 689  * Check a string doesn't overrun the chunk of
 690  * memory we copied from userland.
 691  */
 692 static int invalid_str(char *str, void *end)
 693 {
 694         while ((void *) str < end)
 695                 if (!*str++)
 696                         return 0;
 697
 698         return -EINVAL;
 699 }
 700
 701 static int dev_rename(struct dm_ioctl *param, size_t param_size)
 702 {
 703         int r;
 704         char *new_name = (char *) param + param->data_start;
 705
 706         if (new_name < param->data ||
 707             invalid_str(new_name, (void *) param + param_size)) {
 708                 DMWARN("Invalid new logical volume name supplied.");
 709                 return -EINVAL;
 710         }
 711
 712         r = check_name(new_name);
 713         if (r)
 714                 return r;
 715
 716         param->data_size = 0;
 717         return dm_hash_rename(param->name, new_name);
 718 }
 719
 720 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
 721 {
 722         int r = -EINVAL, x;
 723         struct mapped_device *md;
 724         struct hd_geometry geometry;
 725         unsigned long indata[4];
 726         char *geostr = (char *) param + param->data_start;
 727
 728         md = find_device(param);
 729         if (!md)
 730                 return -ENXIO;
 731
 732         if (geostr < param->data ||
 733             invalid_str(geostr, (void *) param + param_size)) {
 734                 DMWARN("Invalid geometry supplied.");
 735                 goto out;
 736         }
 737
 738         x = sscanf(geostr, "%lu %lu %lu %lu", indata,
 739                    indata + 1, indata + 2, indata + 3);
 740
 741         if (x != 4) {
 742                 DMWARN("Unable to interpret geometry settings.");
 743                 goto out;
 744         }
 745
 746         if (indata[0] > 65535 || indata[1] > 255 ||
 747             indata[2] > 255 || indata[3] > ULONG_MAX) {
 748                 DMWARN("Geometry exceeds range limits.");
 749                 goto out;
 750         }
 751
 752         geometry.cylinders = indata[0];
 753         geometry.heads = indata[1];
 754         geometry.sectors = indata[2];
 755         geometry.start = indata[3];
 756
 757         r = dm_set_geometry(md, &geometry);
 758         if (!r)
 759                 r = __dev_status(md, param);
 760
 761         param->data_size = 0;
 762
 763 out:
 764         dm_put(md);
 765         return r;
 766 }
 767
 768 static int do_suspend(struct dm_ioctl *param)
 769 {
 770         int r = 0;
 771         unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
 772         struct mapped_device *md;
 773
 774         md = find_device(param);
 775         if (!md)
 776                 return -ENXIO;
 777
 778         if (param->flags & DM_SKIP_LOCKFS_FLAG)
 779                 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
 780         if (param->flags & DM_NOFLUSH_FLAG)
 781                 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 782
 783         if (!dm_suspended(md))
 784                 r = dm_suspend(md, suspend_flags);
 785
 786         if (!r)
 787                 r = __dev_status(md, param);
 788
 789         dm_put(md);
 790         return r;
 791 }
 792
 793 static int do_resume(struct dm_ioctl *param)
 794 {
 795         int r = 0;
 796         unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
 797         struct hash_cell *hc;
 798         struct mapped_device *md;
 799         struct dm_table *new_map;
 800
 801         down_write(&_hash_lock);
 802
 803         hc = __find_device_hash_cell(param);
 804         if (!hc) {
 805                 DMWARN("device doesn't appear to be in the dev hash table.");
 806                 up_write(&_hash_lock);
 807                 return -ENXIO;
 808         }
 809
 810         md = hc->md;
 811
 812         new_map = hc->new_map;
 813         hc->new_map = NULL;
 814         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 815
 816         up_write(&_hash_lock);
 817
 818         /* Do we need to load a new map ? */
 819         if (new_map) {
 820                 /* Suspend if it isn't already suspended */
 821                 if (param->flags & DM_SKIP_LOCKFS_FLAG)
 822                         suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
 823                 if (param->flags & DM_NOFLUSH_FLAG)
 824                         suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
 825                 if (!dm_suspended(md))
 826                         dm_suspend(md, suspend_flags);
 827
 828                 r = dm_swap_table(md, new_map);
 829                 if (r) {
 830                         dm_put(md);
 831                         dm_table_put(new_map);
 832                         return r;
 833                 }
 834
 835                 if (dm_table_get_mode(new_map) & FMODE_WRITE)
 836                         set_disk_ro(dm_disk(md), 0);
 837                 else
 838                         set_disk_ro(dm_disk(md), 1);
 839
 840                 dm_table_put(new_map);
 841         }
 842
 843         if (dm_suspended(md))
 844                 r = dm_resume(md);
 845
 846         if (!r)
 847                 r = __dev_status(md, param);
 848
 849         dm_put(md);
 850         return r;
 851 }
 852
 853 /*
 854  * Set or unset the suspension state of a device.
 855  * If the device already is in the requested state we just return its status.
 856  */
 857 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
 858 {
 859         if (param->flags & DM_SUSPEND_FLAG)
 860                 return do_suspend(param);
 861
 862         return do_resume(param);
 863 }
 864
 865 /*
 866  * Copies device info back to user space, used by
 867  * the create and info ioctls.
 868  */
 869 static int dev_status(struct dm_ioctl *param, size_t param_size)
 870 {
 871         int r;
 872         struct mapped_device *md;
 873
 874         md = find_device(param);
 875         if (!md)
 876                 return -ENXIO;
 877
 878         r = __dev_status(md, param);
 879         dm_put(md);
 880         return r;
 881 }
 882
 883 /*
 884  * Build up the status struct for each target
 885  */
 886 static void retrieve_status(struct dm_table *table,
 887                             struct dm_ioctl *param, size_t param_size)
 888 {
 889         unsigned int i, num_targets;
 890         struct dm_target_spec *spec;
 891         char *outbuf, *outptr;
 892         status_type_t type;
 893         size_t remaining, len, used = 0;
 894
 895         outptr = outbuf = get_result_buffer(param, param_size, &len);
 896
 897         if (param->flags & DM_STATUS_TABLE_FLAG)
 898                 type = STATUSTYPE_TABLE;
 899         else
 900                 type = STATUSTYPE_INFO;
 901
 902         /* Get all the target info */
 903         num_targets = dm_table_get_num_targets(table);
 904         for (i = 0; i < num_targets; i++) {
 905                 struct dm_target *ti = dm_table_get_target(table, i);
 906
 907                 remaining = len - (outptr - outbuf);
 908                 if (remaining <= sizeof(struct dm_target_spec)) {
 909                         param->flags |= DM_BUFFER_FULL_FLAG;
 910                         break;
 911                 }
 912
 913                 spec = (struct dm_target_spec *) outptr;
 914
 915                 spec->status = 0;
 916                 spec->sector_start = ti->begin;
 917                 spec->length = ti->len;
 918                 strncpy(spec->target_type, ti->type->name,
 919                         sizeof(spec->target_type));
 920
 921                 outptr += sizeof(struct dm_target_spec);
 922                 remaining = len - (outptr - outbuf);
 923                 if (remaining <= 0) {
 924                         param->flags |= DM_BUFFER_FULL_FLAG;
 925                         break;
 926                 }
 927
 928                 /* Get the status/table string from the target driver */
 929                 if (ti->type->status) {
 930                         if (ti->type->status(ti, type, outptr, remaining)) {
 931                                 param->flags |= DM_BUFFER_FULL_FLAG;
 932                                 break;
 933                         }
 934                 } else
 935                         outptr[0] = '\0';
 936
 937                 outptr += strlen(outptr) + 1;
 938                 used = param->data_start + (outptr - outbuf);
 939
 940                 outptr = align_ptr(outptr);
 941                 spec->next = outptr - outbuf;
 942         }
 943
 944         if (used)
 945                 param->data_size = used;
 946
 947         param->target_count = num_targets;
 948 }
 949
 950 /*
 951  * Wait for a device to report an event
 952  */
 953 static int dev_wait(struct dm_ioctl *param, size_t param_size)
 954 {
 955         int r;
 956         struct mapped_device *md;
 957         struct dm_table *table;
 958
 959         md = find_device(param);
 960         if (!md)
 961                 return -ENXIO;
 962
 963         /*
 964          * Wait for a notification event
 965          */
 966         if (dm_wait_event(md, param->event_nr)) {
 967                 r = -ERESTARTSYS;
 968                 goto out;
 969         }
 970
 971         /*
 972          * The userland program is going to want to know what
 973          * changed to trigger the event, so we may as well tell
 974          * him and save an ioctl.
 975          */
 976         r = __dev_status(md, param);
 977         if (r)
 978                 goto out;
 979
 980         table = dm_get_table(md);
 981         if (table) {
 982                 retrieve_status(table, param, param_size);
 983                 dm_table_put(table);
 984         }
 985
 986  out:
 987         dm_put(md);
 988         return r;
 989 }
 990
 991 static inline fmode_t get_mode(struct dm_ioctl *param)
 992 {
 993         fmode_t mode = FMODE_READ | FMODE_WRITE;
 994
 995         if (param->flags & DM_READONLY_FLAG)
 996                 mode = FMODE_READ;
 997
 998         return mode;
 999 }
1000
1001 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
1002                        struct dm_target_spec **spec, char **target_params)
1003 {
1004         *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1005         *target_params = (char *) (*spec + 1);
1006
1007         if (*spec < (last + 1))
1008                 return -EINVAL;
1009
1010         return invalid_str(*target_params, end);
1011 }
1012
1013 static int populate_table(struct dm_table *table,
1014                           struct dm_ioctl *param, size_t param_size)
1015 {
1016         int r;
1017         unsigned int i = 0;
1018         struct dm_target_spec *spec = (struct dm_target_spec *) param;
1019         uint32_t next = param->data_start;
1020         void *end = (void *) param + param_size;
1021         char *target_params;
1022
1023         if (!param->target_count) {
1024                 DMWARN("populate_table: no targets specified");
1025                 return -EINVAL;
1026         }
1027
1028         for (i = 0; i < param->target_count; i++) {
1029
1030                 r = next_target(spec, next, end, &spec, &target_params);
1031                 if (r) {
1032                         DMWARN("unable to find target");
1033                         return r;
1034                 }
1035
1036                 r = dm_table_add_target(table, spec->target_type,
1037                                         (sector_t) spec->sector_start,
1038                                         (sector_t) spec->length,
1039                                         target_params);
1040                 if (r) {
1041                         DMWARN("error adding target to table");
1042                         return r;
1043                 }
1044
1045                 next = spec->next;
1046         }
1047
1048         return dm_table_complete(table);
1049 }
1050
1051 static int table_load(struct dm_ioctl *param, size_t param_size)
1052 {
1053         int r;
1054         struct hash_cell *hc;
1055         struct dm_table *t;
1056         struct mapped_device *md;
1057
1058         md = find_device(param);
1059         if (!md)
1060                 return -ENXIO;
1061
1062         r = dm_table_create(&t, get_mode(param), param->target_count, md);
1063         if (r)
1064                 goto out;
1065
1066         r = populate_table(t, param, param_size);
1067         if (r) {
1068                 dm_table_put(t);
1069                 goto out;
1070         }
1071
1072         down_write(&_hash_lock);
1073         hc = dm_get_mdptr(md);
1074         if (!hc || hc->md != md) {
1075                 DMWARN("device has been removed from the dev hash table.");
1076                 dm_table_put(t);
1077                 up_write(&_hash_lock);
1078                 r = -ENXIO;
1079                 goto out;
1080         }
1081
1082         if (hc->new_map)
1083                 dm_table_put(hc->new_map);
1084         hc->new_map = t;
1085         up_write(&_hash_lock);
1086
1087         param->flags |= DM_INACTIVE_PRESENT_FLAG;
1088         r = __dev_status(md, param);
1089
1090 out:
1091         dm_put(md);
1092
1093         return r;
1094 }
1095
1096 static int table_clear(struct dm_ioctl *param, size_t param_size)
1097 {
1098         int r;
1099         struct hash_cell *hc;
1100         struct mapped_device *md;
1101
1102         down_write(&_hash_lock);
1103
1104         hc = __find_device_hash_cell(param);
1105         if (!hc) {
1106                 DMWARN("device doesn't appear to be in the dev hash table.");
1107                 up_write(&_hash_lock);
1108                 return -ENXIO;
1109         }
1110
1111         if (hc->new_map) {
1112                 dm_table_put(hc->new_map);
1113                 hc->new_map = NULL;
1114         }
1115
1116         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1117
1118         r = __dev_status(hc->md, param);
1119         md = hc->md;
1120         up_write(&_hash_lock);
1121         dm_put(md);
1122         return r;
1123 }
1124
1125 /*
1126  * Retrieves a list of devices used by a particular dm device.
1127  */
1128 static void retrieve_deps(struct dm_table *table,
1129                           struct dm_ioctl *param, size_t param_size)
1130 {
1131         unsigned int count = 0;
1132         struct list_head *tmp;
1133         size_t len, needed;
1134         struct dm_dev_internal *dd;
1135         struct dm_target_deps *deps;
1136
1137         deps = get_result_buffer(param, param_size, &len);
1138
1139         /*
1140          * Count the devices.
1141          */
1142         list_for_each (tmp, dm_table_get_devices(table))
1143                 count++;
1144
1145         /*
1146          * Check we have enough space.
1147          */
1148         needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1149         if (len < needed) {
1150                 param->flags |= DM_BUFFER_FULL_FLAG;
1151                 return;
1152         }
1153
1154         /*
1155          * Fill in the devices.
1156          */
1157         deps->count = count;
1158         count = 0;
1159         list_for_each_entry (dd, dm_table_get_devices(table), list)
1160                 deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
1161
1162         param->data_size = param->data_start + needed;
1163 }
1164
1165 static int table_deps(struct dm_ioctl *param, size_t param_size)
1166 {
1167         int r = 0;
1168         struct mapped_device *md;
1169         struct dm_table *table;
1170
1171         md = find_device(param);
1172         if (!md)
1173                 return -ENXIO;
1174
1175         r = __dev_status(md, param);
1176         if (r)
1177                 goto out;
1178
1179         table = dm_get_table(md);
1180         if (table) {
1181                 retrieve_deps(table, param, param_size);
1182                 dm_table_put(table);
1183         }
1184
1185  out:
1186         dm_put(md);
1187         return r;
1188 }
1189
1190 /*
1191  * Return the status of a device as a text string for each
1192  * target.
1193  */
1194 static int table_status(struct dm_ioctl *param, size_t param_size)
1195 {
1196         int r;
1197         struct mapped_device *md;
1198         struct dm_table *table;
1199
1200         md = find_device(param);
1201         if (!md)
1202                 return -ENXIO;
1203
1204         r = __dev_status(md, param);
1205         if (r)
1206                 goto out;
1207
1208         table = dm_get_table(md);
1209         if (table) {
1210                 retrieve_status(table, param, param_size);
1211                 dm_table_put(table);
1212         }
1213
1214  out:
1215         dm_put(md);
1216         return r;
1217 }
1218
1219 /*
1220  * Pass a message to the target that's at the supplied device offset.
1221  */
1222 static int target_message(struct dm_ioctl *param, size_t param_size)
1223 {
1224         int r, argc;
1225         char **argv;
1226         struct mapped_device *md;
1227         struct dm_table *table;
1228         struct dm_target *ti;
1229         struct dm_target_msg *tmsg = (void *) param + param->data_start;
1230
1231         md = find_device(param);
1232         if (!md)
1233                 return -ENXIO;
1234
1235         r = __dev_status(md, param);
1236         if (r)
1237                 goto out;
1238
1239         if (tmsg < (struct dm_target_msg *) param->data ||
1240             invalid_str(tmsg->message, (void *) param + param_size)) {
1241                 DMWARN("Invalid target message parameters.");
1242                 r = -EINVAL;
1243                 goto out;
1244         }
1245
1246         r = dm_split_args(&argc, &argv, tmsg->message);
1247         if (r) {
1248                 DMWARN("Failed to split target message parameters");
1249                 goto out;
1250         }
1251
1252         table = dm_get_table(md);
1253         if (!table)
1254                 goto out_argv;
1255
1256         ti = dm_table_find_target(table, tmsg->sector);
1257         if (!dm_target_is_valid(ti)) {
1258                 DMWARN("Target message sector outside device.");
1259                 r = -EINVAL;
1260         } else if (ti->type->message)
1261                 r = ti->type->message(ti, argc, argv);
1262         else {
1263                 DMWARN("Target type does not support messages");
1264                 r = -EINVAL;
1265         }
1266
1267         dm_table_put(table);
1268  out_argv:
1269         kfree(argv);
1270  out:
1271         param->data_size = 0;
1272         dm_put(md);
1273         return r;
1274 }
1275
1276 /*-----------------------------------------------------------------
1277  * Implementation of open/close/ioctl on the special char
1278  * device.
1279  *---------------------------------------------------------------*/
1280 static ioctl_fn lookup_ioctl(unsigned int cmd)
1281 {
1282         static struct {
1283                 int cmd;
1284                 ioctl_fn fn;
1285         } _ioctls[] = {
1286                 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1287                 {DM_REMOVE_ALL_CMD, remove_all},
1288                 {DM_LIST_DEVICES_CMD, list_devices},
1289
1290                 {DM_DEV_CREATE_CMD, dev_create},
1291                 {DM_DEV_REMOVE_CMD, dev_remove},
1292                 {DM_DEV_RENAME_CMD, dev_rename},
1293                 {DM_DEV_SUSPEND_CMD, dev_suspend},
1294                 {DM_DEV_STATUS_CMD, dev_status},
1295                 {DM_DEV_WAIT_CMD, dev_wait},
1296
1297                 {DM_TABLE_LOAD_CMD, table_load},
1298                 {DM_TABLE_CLEAR_CMD, table_clear},
1299                 {DM_TABLE_DEPS_CMD, table_deps},
1300                 {DM_TABLE_STATUS_CMD, table_status},
1301
1302                 {DM_LIST_VERSIONS_CMD, list_versions},
1303
1304                 {DM_TARGET_MSG_CMD, target_message},
1305                 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
1306         };
1307
1308         return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1309 }
1310
1311 /*
1312  * As well as checking the version compatibility this always
1313  * copies the kernel interface version out.
1314  */
1315 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1316 {
1317         uint32_t version[3];
1318         int r = 0;
1319
1320         if (copy_from_user(version, user->version, sizeof(version)))
1321                 return -EFAULT;
1322
1323         if ((DM_VERSION_MAJOR != version[0]) ||
1324             (DM_VERSION_MINOR < version[1])) {
1325                 DMWARN("ioctl interface mismatch: "
1326                        "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1327                        DM_VERSION_MAJOR, DM_VERSION_MINOR,
1328                        DM_VERSION_PATCHLEVEL,
1329                        version[0], version[1], version[2], cmd);
1330                 r = -EINVAL;
1331         }
1332
1333         /*
1334          * Fill in the kernel version.
1335          */
1336         version[0] = DM_VERSION_MAJOR;
1337         version[1] = DM_VERSION_MINOR;
1338         version[2] = DM_VERSION_PATCHLEVEL;
1339         if (copy_to_user(user->version, version, sizeof(version)))
1340                 return -EFAULT;
1341
1342         return r;
1343 }
1344
1345 static void free_params(struct dm_ioctl *param)
1346 {
1347         vfree(param);
1348 }
1349
1350 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1351 {
1352         struct dm_ioctl tmp, *dmi;
1353
1354         if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
1355                 return -EFAULT;
1356
1357         if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
1358                 return -EINVAL;
1359
1360         dmi = vmalloc(tmp.data_size);
1361         if (!dmi)
1362                 return -ENOMEM;
1363
1364         if (copy_from_user(dmi, user, tmp.data_size)) {
1365                 vfree(dmi);
1366                 return -EFAULT;
1367         }
1368
1369         *param = dmi;
1370         return 0;
1371 }
1372
1373 static int validate_params(uint cmd, struct dm_ioctl *param)
1374 {
1375         /* Always clear this flag */
1376         param->flags &= ~DM_BUFFER_FULL_FLAG;
1377
1378         /* Ignores parameters */
1379         if (cmd == DM_REMOVE_ALL_CMD ||
1380             cmd == DM_LIST_DEVICES_CMD ||
1381             cmd == DM_LIST_VERSIONS_CMD)
1382                 return 0;
1383
1384         if ((cmd == DM_DEV_CREATE_CMD)) {
1385                 if (!*param->name) {
1386                         DMWARN("name not supplied when creating device");
1387                         return -EINVAL;
1388                 }
1389         } else if ((*param->uuid && *param->name)) {
1390                 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1391                 return -EINVAL;
1392         }
1393
1394         /* Ensure strings are terminated */
1395         param->name[DM_NAME_LEN - 1] = '\0';
1396         param->uuid[DM_UUID_LEN - 1] = '\0';
1397
1398         return 0;
1399 }
1400
1401 static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
1402 {
1403         int r = 0;
1404         unsigned int cmd;
1405         struct dm_ioctl *uninitialized_var(param);
1406         ioctl_fn fn = NULL;
1407         size_t param_size;
1408
1409         /* only root can play with this */
1410         if (!capable(CAP_SYS_ADMIN))
1411                 return -EACCES;
1412
1413         if (_IOC_TYPE(command) != DM_IOCTL)
1414                 return -ENOTTY;
1415
1416         cmd = _IOC_NR(command);
1417
1418         /*
1419          * Check the interface version passed in.  This also
1420          * writes out the kernel's interface version.
1421          */
1422         r = check_version(cmd, user);
1423         if (r)
1424                 return r;
1425
1426         /*
1427          * Nothing more to do for the version command.
1428          */
1429         if (cmd == DM_VERSION_CMD)
1430                 return 0;
1431
1432         fn = lookup_ioctl(cmd);
1433         if (!fn) {
1434                 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1435                 return -ENOTTY;
1436         }
1437
1438         /*
1439          * Trying to avoid low memory issues when a device is
1440          * suspended.
1441          */
1442         current->flags |= PF_MEMALLOC;
1443
1444         /*
1445          * Copy the parameters into kernel space.
1446          */
1447         r = copy_params(user, &param);
1448
1449         current->flags &= ~PF_MEMALLOC;
1450
1451         if (r)
1452                 return r;
1453
1454         r = validate_params(cmd, param);
1455         if (r)
1456                 goto out;
1457
1458         param_size = param->data_size;
1459         param->data_size = sizeof(*param);
1460         r = fn(param, param_size);
1461
1462         /*
1463          * Copy the results back to userland.
1464          */
1465         if (!r && copy_to_user(user, param, param->data_size))
1466                 r = -EFAULT;
1467
1468  out:
1469         free_params(param);
1470         return r;
1471 }
1472
1473 static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
1474 {
1475         return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
1476 }
1477
1478 #ifdef CONFIG_COMPAT
1479 static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
1480 {
1481         return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
1482 }
1483 #else
1484 #define dm_compat_ctl_ioctl NULL
1485 #endif
1486
1487 static const struct file_operations _ctl_fops = {
1488         .unlocked_ioctl  = dm_ctl_ioctl,
1489         .compat_ioctl = dm_compat_ctl_ioctl,
1490         .owner   = THIS_MODULE,
1491 };
1492
1493 static struct miscdevice _dm_misc = {
1494         .minor          = MISC_DYNAMIC_MINOR,
1495         .name           = DM_NAME,
1496         .fops           = &_ctl_fops
1497 };
1498
1499 /*
1500  * Create misc character device and link to DM_DIR/control.
1501  */
1502 int __init dm_interface_init(void)
1503 {
1504         int r;
1505
1506         r = dm_hash_init();
1507         if (r)
1508                 return r;
1509
1510         r = misc_register(&_dm_misc);
1511         if (r) {
1512                 DMERR("misc_register failed for control device");
1513                 dm_hash_exit();
1514                 return r;
1515         }
1516
1517         DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1518                DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1519                DM_DRIVER_EMAIL);
1520         return 0;
1521 }
1522
1523 void dm_interface_exit(void)
1524 {
1525         if (misc_deregister(&_dm_misc) < 0)
1526                 DMERR("misc_deregister failed for control device");
1527
1528         dm_hash_exit();
1529 }
1530
1531 /**
1532  * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
1533  * @md: Pointer to mapped_device
1534  * @name: Buffer (size DM_NAME_LEN) for name
1535  * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
1536  */
1537 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
1538 {
1539         int r = 0;
1540         struct hash_cell *hc;
1541
1542         if (!md)
1543                 return -ENXIO;
1544
1545         dm_get(md);
1546         down_read(&_hash_lock);
1547         hc = dm_get_mdptr(md);
1548         if (!hc || hc->md != md) {
1549                 r = -ENXIO;
1550                 goto out;
1551         }
1552
1553         strcpy(name, hc->name);
1554         strcpy(uuid, hc->uuid ? : "");
1555
1556 out:
1557         up_read(&_hash_lock);
1558         dm_put(md);
1559
1560         return r;
1561 }