drivers/md/dm-ioctl.c

   1 /*
   2  * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
   3  * Copyright (C) 2004 - 2005 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/devfs_fs_kernel.h>
  17 #include <linux/dm-ioctl.h>
  18
  19 #include <asm/uaccess.h>
  20
  21 #define DM_DRIVER_EMAIL "dm-devel@redhat.com"
  22
  23 /*-----------------------------------------------------------------
  24  * The ioctl interface needs to be able to look up devices by
  25  * name or uuid.
  26  *---------------------------------------------------------------*/
  27 struct hash_cell {
  28         struct list_head name_list;
  29         struct list_head uuid_list;
  30
  31         char *name;
  32         char *uuid;
  33         struct mapped_device *md;
  34         struct dm_table *new_map;
  35 };
  36
  37 struct vers_iter {
  38     size_t param_size;
  39     struct dm_target_versions *vers, *old_vers;
  40     char *end;
  41     uint32_t flags;
  42 };
  43
  44
  45 #define NUM_BUCKETS 64
  46 #define MASK_BUCKETS (NUM_BUCKETS - 1)
  47 static struct list_head _name_buckets[NUM_BUCKETS];
  48 static struct list_head _uuid_buckets[NUM_BUCKETS];
  49
  50 static void dm_hash_remove_all(void);
  51
  52 /*
  53  * Guards access to both hash tables.
  54  */
  55 static DECLARE_RWSEM(_hash_lock);
  56
  57 static void init_buckets(struct list_head *buckets)
  58 {
  59         unsigned int i;
  60
  61         for (i = 0; i < NUM_BUCKETS; i++)
  62                 INIT_LIST_HEAD(buckets + i);
  63 }
  64
  65 static int dm_hash_init(void)
  66 {
  67         init_buckets(_name_buckets);
  68         init_buckets(_uuid_buckets);
  69         devfs_mk_dir(DM_DIR);
  70         return 0;
  71 }
  72
  73 static void dm_hash_exit(void)
  74 {
  75         dm_hash_remove_all();
  76         devfs_remove(DM_DIR);
  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                         return hc;
 106
 107         return NULL;
 108 }
 109
 110 static struct hash_cell *__get_uuid_cell(const char *str)
 111 {
 112         struct hash_cell *hc;
 113         unsigned int h = hash_str(str);
 114
 115         list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
 116                 if (!strcmp(hc->uuid, str))
 117                         return hc;
 118
 119         return NULL;
 120 }
 121
 122 /*-----------------------------------------------------------------
 123  * Inserting, removing and renaming a device.
 124  *---------------------------------------------------------------*/
 125 static struct hash_cell *alloc_cell(const char *name, const char *uuid,
 126                                     struct mapped_device *md)
 127 {
 128         struct hash_cell *hc;
 129
 130         hc = kmalloc(sizeof(*hc), GFP_KERNEL);
 131         if (!hc)
 132                 return NULL;
 133
 134         hc->name = kstrdup(name, GFP_KERNEL);
 135         if (!hc->name) {
 136                 kfree(hc);
 137                 return NULL;
 138         }
 139
 140         if (!uuid)
 141                 hc->uuid = NULL;
 142
 143         else {
 144                 hc->uuid = kstrdup(uuid, GFP_KERNEL);
 145                 if (!hc->uuid) {
 146                         kfree(hc->name);
 147                         kfree(hc);
 148                         return NULL;
 149                 }
 150         }
 151
 152         INIT_LIST_HEAD(&hc->name_list);
 153         INIT_LIST_HEAD(&hc->uuid_list);
 154         hc->md = md;
 155         hc->new_map = NULL;
 156         return hc;
 157 }
 158
 159 static void free_cell(struct hash_cell *hc)
 160 {
 161         if (hc) {
 162                 kfree(hc->name);
 163                 kfree(hc->uuid);
 164                 kfree(hc);
 165         }
 166 }
 167
 168 /*
 169  * devfs stuff.
 170  */
 171 static int register_with_devfs(struct hash_cell *hc)
 172 {
 173         struct gendisk *disk = dm_disk(hc->md);
 174
 175         devfs_mk_bdev(MKDEV(disk->major, disk->first_minor),
 176                       S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
 177                       DM_DIR "/%s", hc->name);
 178         return 0;
 179 }
 180
 181 static int unregister_with_devfs(struct hash_cell *hc)
 182 {
 183         devfs_remove(DM_DIR"/%s", hc->name);
 184         return 0;
 185 }
 186
 187 /*
 188  * The kdev_t and uuid of a device can never change once it is
 189  * initially inserted.
 190  */
 191 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
 192 {
 193         struct hash_cell *cell;
 194
 195         /*
 196          * Allocate the new cells.
 197          */
 198         cell = alloc_cell(name, uuid, md);
 199         if (!cell)
 200                 return -ENOMEM;
 201
 202         /*
 203          * Insert the cell into both hash tables.
 204          */
 205         down_write(&_hash_lock);
 206         if (__get_name_cell(name))
 207                 goto bad;
 208
 209         list_add(&cell->name_list, _name_buckets + hash_str(name));
 210
 211         if (uuid) {
 212                 if (__get_uuid_cell(uuid)) {
 213                         list_del(&cell->name_list);
 214                         goto bad;
 215                 }
 216                 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
 217         }
 218         register_with_devfs(cell);
 219         dm_get(md);
 220         dm_set_mdptr(md, cell);
 221         up_write(&_hash_lock);
 222
 223         return 0;
 224
 225  bad:
 226         up_write(&_hash_lock);
 227         free_cell(cell);
 228         return -EBUSY;
 229 }
 230
 231 static void __hash_remove(struct hash_cell *hc)
 232 {
 233         struct dm_table *table;
 234
 235         /* remove from the dev hash */
 236         list_del(&hc->uuid_list);
 237         list_del(&hc->name_list);
 238         unregister_with_devfs(hc);
 239         dm_set_mdptr(hc->md, NULL);
 240
 241         table = dm_get_table(hc->md);
 242         if (table) {
 243                 dm_table_event(table);
 244                 dm_table_put(table);
 245         }
 246
 247         dm_put(hc->md);
 248         if (hc->new_map)
 249                 dm_table_put(hc->new_map);
 250         free_cell(hc);
 251 }
 252
 253 static void dm_hash_remove_all(void)
 254 {
 255         int i;
 256         struct hash_cell *hc;
 257         struct list_head *tmp, *n;
 258
 259         down_write(&_hash_lock);
 260         for (i = 0; i < NUM_BUCKETS; i++) {
 261                 list_for_each_safe (tmp, n, _name_buckets + i) {
 262                         hc = list_entry(tmp, struct hash_cell, name_list);
 263                         __hash_remove(hc);
 264                 }
 265         }
 266         up_write(&_hash_lock);
 267 }
 268
 269 static int dm_hash_rename(const char *old, const char *new)
 270 {
 271         char *new_name, *old_name;
 272         struct hash_cell *hc;
 273
 274         /*
 275          * duplicate new.
 276          */
 277         new_name = kstrdup(new, GFP_KERNEL);
 278         if (!new_name)
 279                 return -ENOMEM;
 280
 281         down_write(&_hash_lock);
 282
 283         /*
 284          * Is new free ?
 285          */
 286         hc = __get_name_cell(new);
 287         if (hc) {
 288                 DMWARN("asked to rename to an already existing name %s -> %s",
 289                        old, new);
 290                 up_write(&_hash_lock);
 291                 kfree(new_name);
 292                 return -EBUSY;
 293         }
 294
 295         /*
 296          * Is there such a device as 'old' ?
 297          */
 298         hc = __get_name_cell(old);
 299         if (!hc) {
 300                 DMWARN("asked to rename a non existent device %s -> %s",
 301                        old, new);
 302                 up_write(&_hash_lock);
 303                 kfree(new_name);
 304                 return -ENXIO;
 305         }
 306
 307         /*
 308          * rename and move the name cell.
 309          */
 310         unregister_with_devfs(hc);
 311
 312         list_del(&hc->name_list);
 313         old_name = hc->name;
 314         hc->name = new_name;
 315         list_add(&hc->name_list, _name_buckets + hash_str(new_name));
 316
 317         /* rename the device node in devfs */
 318         register_with_devfs(hc);
 319
 320         up_write(&_hash_lock);
 321         kfree(old_name);
 322         return 0;
 323 }
 324
 325 /*-----------------------------------------------------------------
 326  * Implementation of the ioctl commands
 327  *---------------------------------------------------------------*/
 328 /*
 329  * All the ioctl commands get dispatched to functions with this
 330  * prototype.
 331  */
 332 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
 333
 334 static int remove_all(struct dm_ioctl *param, size_t param_size)
 335 {
 336         dm_hash_remove_all();
 337         param->data_size = 0;
 338         return 0;
 339 }
 340
 341 /*
 342  * Round up the ptr to an 8-byte boundary.
 343  */
 344 #define ALIGN_MASK 7
 345 static inline void *align_ptr(void *ptr)
 346 {
 347         return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
 348 }
 349
 350 /*
 351  * Retrieves the data payload buffer from an already allocated
 352  * struct dm_ioctl.
 353  */
 354 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
 355                                size_t *len)
 356 {
 357         param->data_start = align_ptr(param + 1) - (void *) param;
 358
 359         if (param->data_start < param_size)
 360                 *len = param_size - param->data_start;
 361         else
 362                 *len = 0;
 363
 364         return ((void *) param) + param->data_start;
 365 }
 366
 367 static int list_devices(struct dm_ioctl *param, size_t param_size)
 368 {
 369         unsigned int i;
 370         struct hash_cell *hc;
 371         size_t len, needed = 0;
 372         struct gendisk *disk;
 373         struct dm_name_list *nl, *old_nl = NULL;
 374
 375         down_write(&_hash_lock);
 376
 377         /*
 378          * Loop through all the devices working out how much
 379          * space we need.
 380          */
 381         for (i = 0; i < NUM_BUCKETS; i++) {
 382                 list_for_each_entry (hc, _name_buckets + i, name_list) {
 383                         needed += sizeof(struct dm_name_list);
 384                         needed += strlen(hc->name) + 1;
 385                         needed += ALIGN_MASK;
 386                 }
 387         }
 388
 389         /*
 390          * Grab our output buffer.
 391          */
 392         nl = get_result_buffer(param, param_size, &len);
 393         if (len < needed) {
 394                 param->flags |= DM_BUFFER_FULL_FLAG;
 395                 goto out;
 396         }
 397         param->data_size = param->data_start + needed;
 398
 399         nl->dev = 0;    /* Flags no data */
 400
 401         /*
 402          * Now loop through filling out the names.
 403          */
 404         for (i = 0; i < NUM_BUCKETS; i++) {
 405                 list_for_each_entry (hc, _name_buckets + i, name_list) {
 406                         if (old_nl)
 407                                 old_nl->next = (uint32_t) ((void *) nl -
 408                                                            (void *) old_nl);
 409                         disk = dm_disk(hc->md);
 410                         nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
 411                         nl->next = 0;
 412                         strcpy(nl->name, hc->name);
 413
 414                         old_nl = nl;
 415                         nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
 416                 }
 417         }
 418
 419  out:
 420         up_write(&_hash_lock);
 421         return 0;
 422 }
 423
 424 static void list_version_get_needed(struct target_type *tt, void *needed_param)
 425 {
 426     size_t *needed = needed_param;
 427
 428     *needed += strlen(tt->name);
 429     *needed += sizeof(tt->version);
 430     *needed += ALIGN_MASK;
 431 }
 432
 433 static void list_version_get_info(struct target_type *tt, void *param)
 434 {
 435     struct vers_iter *info = param;
 436
 437     /* Check space - it might have changed since the first iteration */
 438     if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
 439         info->end) {
 440
 441         info->flags = DM_BUFFER_FULL_FLAG;
 442         return;
 443     }
 444
 445     if (info->old_vers)
 446         info->old_vers->next = (uint32_t) ((void *)info->vers -
 447                                            (void *)info->old_vers);
 448     info->vers->version[0] = tt->version[0];
 449     info->vers->version[1] = tt->version[1];
 450     info->vers->version[2] = tt->version[2];
 451     info->vers->next = 0;
 452     strcpy(info->vers->name, tt->name);
 453
 454     info->old_vers = info->vers;
 455     info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
 456 }
 457
 458 static int list_versions(struct dm_ioctl *param, size_t param_size)
 459 {
 460         size_t len, needed = 0;
 461         struct dm_target_versions *vers;
 462         struct vers_iter iter_info;
 463
 464         /*
 465          * Loop through all the devices working out how much
 466          * space we need.
 467          */
 468         dm_target_iterate(list_version_get_needed, &needed);
 469
 470         /*
 471          * Grab our output buffer.
 472          */
 473         vers = get_result_buffer(param, param_size, &len);
 474         if (len < needed) {
 475                 param->flags |= DM_BUFFER_FULL_FLAG;
 476                 goto out;
 477         }
 478         param->data_size = param->data_start + needed;
 479
 480         iter_info.param_size = param_size;
 481         iter_info.old_vers = NULL;
 482         iter_info.vers = vers;
 483         iter_info.flags = 0;
 484         iter_info.end = (char *)vers+len;
 485
 486         /*
 487          * Now loop through filling out the names & versions.
 488          */
 489         dm_target_iterate(list_version_get_info, &iter_info);
 490         param->flags |= iter_info.flags;
 491
 492  out:
 493         return 0;
 494 }
 495
 496
 497
 498 static int check_name(const char *name)
 499 {
 500         if (strchr(name, '/')) {
 501                 DMWARN("invalid device name");
 502                 return -EINVAL;
 503         }
 504
 505         return 0;
 506 }
 507
 508 /*
 509  * Fills in a dm_ioctl structure, ready for sending back to
 510  * userland.
 511  */
 512 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 513 {
 514         struct gendisk *disk = dm_disk(md);
 515         struct dm_table *table;
 516         struct block_device *bdev;
 517
 518         param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
 519                           DM_ACTIVE_PRESENT_FLAG);
 520
 521         if (dm_suspended(md))
 522                 param->flags |= DM_SUSPEND_FLAG;
 523
 524         param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
 525
 526         if (!(param->flags & DM_SKIP_BDGET_FLAG)) {
 527                 bdev = bdget_disk(disk, 0);
 528                 if (!bdev)
 529                         return -ENXIO;
 530
 531                 /*
 532                  * Yes, this will be out of date by the time it gets back
 533                  * to userland, but it is still very useful for
 534                  * debugging.
 535                  */
 536                 param->open_count = bdev->bd_openers;
 537                 bdput(bdev);
 538         } else
 539                 param->open_count = -1;
 540
 541         if (disk->policy)
 542                 param->flags |= DM_READONLY_FLAG;
 543
 544         param->event_nr = dm_get_event_nr(md);
 545
 546         table = dm_get_table(md);
 547         if (table) {
 548                 param->flags |= DM_ACTIVE_PRESENT_FLAG;
 549                 param->target_count = dm_table_get_num_targets(table);
 550                 dm_table_put(table);
 551         } else
 552                 param->target_count = 0;
 553
 554         return 0;
 555 }
 556
 557 static int dev_create(struct dm_ioctl *param, size_t param_size)
 558 {
 559         int r;
 560         struct mapped_device *md;
 561
 562         r = check_name(param->name);
 563         if (r)
 564                 return r;
 565
 566         if (param->flags & DM_PERSISTENT_DEV_FLAG)
 567                 r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md);
 568         else
 569                 r = dm_create(&md);
 570
 571         if (r)
 572                 return r;
 573
 574         r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
 575         if (r) {
 576                 dm_put(md);
 577                 return r;
 578         }
 579
 580         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 581
 582         r = __dev_status(md, param);
 583         dm_put(md);
 584
 585         return r;
 586 }
 587
 588 /*
 589  * Always use UUID for lookups if it's present, otherwise use name or dev.
 590  */
 591 static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
 592 {
 593         if (*param->uuid)
 594                 return __get_uuid_cell(param->uuid);
 595         else if (*param->name)
 596                 return __get_name_cell(param->name);
 597         else
 598                 return dm_get_mdptr(huge_decode_dev(param->dev));
 599 }
 600
 601 static inline struct mapped_device *find_device(struct dm_ioctl *param)
 602 {
 603         struct hash_cell *hc;
 604         struct mapped_device *md = NULL;
 605
 606         down_read(&_hash_lock);
 607         hc = __find_device_hash_cell(param);
 608         if (hc) {
 609                 md = hc->md;
 610                 dm_get(md);
 611
 612                 /*
 613                  * Sneakily write in both the name and the uuid
 614                  * while we have the cell.
 615                  */
 616                 strncpy(param->name, hc->name, sizeof(param->name));
 617                 if (hc->uuid)
 618                         strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
 619                 else
 620                         param->uuid[0] = '\0';
 621
 622                 if (hc->new_map)
 623                         param->flags |= DM_INACTIVE_PRESENT_FLAG;
 624                 else
 625                         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 626         }
 627         up_read(&_hash_lock);
 628
 629         return md;
 630 }
 631
 632 static int dev_remove(struct dm_ioctl *param, size_t param_size)
 633 {
 634         struct hash_cell *hc;
 635
 636         down_write(&_hash_lock);
 637         hc = __find_device_hash_cell(param);
 638
 639         if (!hc) {
 640                 DMWARN("device doesn't appear to be in the dev hash table.");
 641                 up_write(&_hash_lock);
 642                 return -ENXIO;
 643         }
 644
 645         __hash_remove(hc);
 646         up_write(&_hash_lock);
 647         param->data_size = 0;
 648         return 0;
 649 }
 650
 651 /*
 652  * Check a string doesn't overrun the chunk of
 653  * memory we copied from userland.
 654  */
 655 static int invalid_str(char *str, void *end)
 656 {
 657         while ((void *) str < end)
 658                 if (!*str++)
 659                         return 0;
 660
 661         return -EINVAL;
 662 }
 663
 664 static int dev_rename(struct dm_ioctl *param, size_t param_size)
 665 {
 666         int r;
 667         char *new_name = (char *) param + param->data_start;
 668
 669         if (new_name < (char *) (param + 1) ||
 670             invalid_str(new_name, (void *) param + param_size)) {
 671                 DMWARN("Invalid new logical volume name supplied.");
 672                 return -EINVAL;
 673         }
 674
 675         r = check_name(new_name);
 676         if (r)
 677                 return r;
 678
 679         param->data_size = 0;
 680         return dm_hash_rename(param->name, new_name);
 681 }
 682
 683 static int do_suspend(struct dm_ioctl *param)
 684 {
 685         int r = 0;
 686         struct mapped_device *md;
 687
 688         md = find_device(param);
 689         if (!md)
 690                 return -ENXIO;
 691
 692         if (!dm_suspended(md))
 693                 r = dm_suspend(md);
 694
 695         if (!r)
 696                 r = __dev_status(md, param);
 697
 698         dm_put(md);
 699         return r;
 700 }
 701
 702 static int do_resume(struct dm_ioctl *param)
 703 {
 704         int r = 0;
 705         struct hash_cell *hc;
 706         struct mapped_device *md;
 707         struct dm_table *new_map;
 708
 709         down_write(&_hash_lock);
 710
 711         hc = __find_device_hash_cell(param);
 712         if (!hc) {
 713                 DMWARN("device doesn't appear to be in the dev hash table.");
 714                 up_write(&_hash_lock);
 715                 return -ENXIO;
 716         }
 717
 718         md = hc->md;
 719         dm_get(md);
 720
 721         new_map = hc->new_map;
 722         hc->new_map = NULL;
 723         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 724
 725         up_write(&_hash_lock);
 726
 727         /* Do we need to load a new map ? */
 728         if (new_map) {
 729                 /* Suspend if it isn't already suspended */
 730                 if (!dm_suspended(md))
 731                         dm_suspend(md);
 732
 733                 r = dm_swap_table(md, new_map);
 734                 if (r) {
 735                         dm_put(md);
 736                         dm_table_put(new_map);
 737                         return r;
 738                 }
 739
 740                 if (dm_table_get_mode(new_map) & FMODE_WRITE)
 741                         set_disk_ro(dm_disk(md), 0);
 742                 else
 743                         set_disk_ro(dm_disk(md), 1);
 744
 745                 dm_table_put(new_map);
 746         }
 747
 748         if (dm_suspended(md))
 749                 r = dm_resume(md);
 750
 751         if (!r)
 752                 r = __dev_status(md, param);
 753
 754         dm_put(md);
 755         return r;
 756 }
 757
 758 /*
 759  * Set or unset the suspension state of a device.
 760  * If the device already is in the requested state we just return its status.
 761  */
 762 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
 763 {
 764         if (param->flags & DM_SUSPEND_FLAG)
 765                 return do_suspend(param);
 766
 767         return do_resume(param);
 768 }
 769
 770 /*
 771  * Copies device info back to user space, used by
 772  * the create and info ioctls.
 773  */
 774 static int dev_status(struct dm_ioctl *param, size_t param_size)
 775 {
 776         int r;
 777         struct mapped_device *md;
 778
 779         md = find_device(param);
 780         if (!md)
 781                 return -ENXIO;
 782
 783         r = __dev_status(md, param);
 784         dm_put(md);
 785         return r;
 786 }
 787
 788 /*
 789  * Build up the status struct for each target
 790  */
 791 static void retrieve_status(struct dm_table *table,
 792                             struct dm_ioctl *param, size_t param_size)
 793 {
 794         unsigned int i, num_targets;
 795         struct dm_target_spec *spec;
 796         char *outbuf, *outptr;
 797         status_type_t type;
 798         size_t remaining, len, used = 0;
 799
 800         outptr = outbuf = get_result_buffer(param, param_size, &len);
 801
 802         if (param->flags & DM_STATUS_TABLE_FLAG)
 803                 type = STATUSTYPE_TABLE;
 804         else
 805                 type = STATUSTYPE_INFO;
 806
 807         /* Get all the target info */
 808         num_targets = dm_table_get_num_targets(table);
 809         for (i = 0; i < num_targets; i++) {
 810                 struct dm_target *ti = dm_table_get_target(table, i);
 811
 812                 remaining = len - (outptr - outbuf);
 813                 if (remaining <= sizeof(struct dm_target_spec)) {
 814                         param->flags |= DM_BUFFER_FULL_FLAG;
 815                         break;
 816                 }
 817
 818                 spec = (struct dm_target_spec *) outptr;
 819
 820                 spec->status = 0;
 821                 spec->sector_start = ti->begin;
 822                 spec->length = ti->len;
 823                 strncpy(spec->target_type, ti->type->name,
 824                         sizeof(spec->target_type));
 825
 826                 outptr += sizeof(struct dm_target_spec);
 827                 remaining = len - (outptr - outbuf);
 828                 if (remaining <= 0) {
 829                         param->flags |= DM_BUFFER_FULL_FLAG;
 830                         break;
 831                 }
 832
 833                 /* Get the status/table string from the target driver */
 834                 if (ti->type->status) {
 835                         if (ti->type->status(ti, type, outptr, remaining)) {
 836                                 param->flags |= DM_BUFFER_FULL_FLAG;
 837                                 break;
 838                         }
 839                 } else
 840                         outptr[0] = '\0';
 841
 842                 outptr += strlen(outptr) + 1;
 843                 used = param->data_start + (outptr - outbuf);
 844
 845                 outptr = align_ptr(outptr);
 846                 spec->next = outptr - outbuf;
 847         }
 848
 849         if (used)
 850                 param->data_size = used;
 851
 852         param->target_count = num_targets;
 853 }
 854
 855 /*
 856  * Wait for a device to report an event
 857  */
 858 static int dev_wait(struct dm_ioctl *param, size_t param_size)
 859 {
 860         int r;
 861         struct mapped_device *md;
 862         struct dm_table *table;
 863
 864         md = find_device(param);
 865         if (!md)
 866                 return -ENXIO;
 867
 868         /*
 869          * Wait for a notification event
 870          */
 871         if (dm_wait_event(md, param->event_nr)) {
 872                 r = -ERESTARTSYS;
 873                 goto out;
 874         }
 875
 876         /*
 877          * The userland program is going to want to know what
 878          * changed to trigger the event, so we may as well tell
 879          * him and save an ioctl.
 880          */
 881         r = __dev_status(md, param);
 882         if (r)
 883                 goto out;
 884
 885         table = dm_get_table(md);
 886         if (table) {
 887                 retrieve_status(table, param, param_size);
 888                 dm_table_put(table);
 889         }
 890
 891  out:
 892         dm_put(md);
 893         return r;
 894 }
 895
 896 static inline int get_mode(struct dm_ioctl *param)
 897 {
 898         int mode = FMODE_READ | FMODE_WRITE;
 899
 900         if (param->flags & DM_READONLY_FLAG)
 901                 mode = FMODE_READ;
 902
 903         return mode;
 904 }
 905
 906 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
 907                        struct dm_target_spec **spec, char **target_params)
 908 {
 909         *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
 910         *target_params = (char *) (*spec + 1);
 911
 912         if (*spec < (last + 1))
 913                 return -EINVAL;
 914
 915         return invalid_str(*target_params, end);
 916 }
 917
 918 static int populate_table(struct dm_table *table,
 919                           struct dm_ioctl *param, size_t param_size)
 920 {
 921         int r;
 922         unsigned int i = 0;
 923         struct dm_target_spec *spec = (struct dm_target_spec *) param;
 924         uint32_t next = param->data_start;
 925         void *end = (void *) param + param_size;
 926         char *target_params;
 927
 928         if (!param->target_count) {
 929                 DMWARN("populate_table: no targets specified");
 930                 return -EINVAL;
 931         }
 932
 933         for (i = 0; i < param->target_count; i++) {
 934
 935                 r = next_target(spec, next, end, &spec, &target_params);
 936                 if (r) {
 937                         DMWARN("unable to find target");
 938                         return r;
 939                 }
 940
 941                 r = dm_table_add_target(table, spec->target_type,
 942                                         (sector_t) spec->sector_start,
 943                                         (sector_t) spec->length,
 944                                         target_params);
 945                 if (r) {
 946                         DMWARN("error adding target to table");
 947                         return r;
 948                 }
 949
 950                 next = spec->next;
 951         }
 952
 953         return dm_table_complete(table);
 954 }
 955
 956 static int table_load(struct dm_ioctl *param, size_t param_size)
 957 {
 958         int r;
 959         struct hash_cell *hc;
 960         struct dm_table *t;
 961
 962         r = dm_table_create(&t, get_mode(param), param->target_count);
 963         if (r)
 964                 return r;
 965
 966         r = populate_table(t, param, param_size);
 967         if (r) {
 968                 dm_table_put(t);
 969                 return r;
 970         }
 971
 972         down_write(&_hash_lock);
 973         hc = __find_device_hash_cell(param);
 974         if (!hc) {
 975                 DMWARN("device doesn't appear to be in the dev hash table.");
 976                 up_write(&_hash_lock);
 977                 return -ENXIO;
 978         }
 979
 980         if (hc->new_map)
 981                 dm_table_put(hc->new_map);
 982         hc->new_map = t;
 983         param->flags |= DM_INACTIVE_PRESENT_FLAG;
 984
 985         r = __dev_status(hc->md, param);
 986         up_write(&_hash_lock);
 987         return r;
 988 }
 989
 990 static int table_clear(struct dm_ioctl *param, size_t param_size)
 991 {
 992         int r;
 993         struct hash_cell *hc;
 994
 995         down_write(&_hash_lock);
 996
 997         hc = __find_device_hash_cell(param);
 998         if (!hc) {
 999                 DMWARN("device doesn't appear to be in the dev hash table.");
1000                 up_write(&_hash_lock);
1001                 return -ENXIO;
1002         }
1003
1004         if (hc->new_map) {
1005                 dm_table_put(hc->new_map);
1006                 hc->new_map = NULL;
1007         }
1008
1009         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1010
1011         r = __dev_status(hc->md, param);
1012         up_write(&_hash_lock);
1013         return r;
1014 }
1015
1016 /*
1017  * Retrieves a list of devices used by a particular dm device.
1018  */
1019 static void retrieve_deps(struct dm_table *table,
1020                           struct dm_ioctl *param, size_t param_size)
1021 {
1022         unsigned int count = 0;
1023         struct list_head *tmp;
1024         size_t len, needed;
1025         struct dm_dev *dd;
1026         struct dm_target_deps *deps;
1027
1028         deps = get_result_buffer(param, param_size, &len);
1029
1030         /*
1031          * Count the devices.
1032          */
1033         list_for_each (tmp, dm_table_get_devices(table))
1034                 count++;
1035
1036         /*
1037          * Check we have enough space.
1038          */
1039         needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1040         if (len < needed) {
1041                 param->flags |= DM_BUFFER_FULL_FLAG;
1042                 return;
1043         }
1044
1045         /*
1046          * Fill in the devices.
1047          */
1048         deps->count = count;
1049         count = 0;
1050         list_for_each_entry (dd, dm_table_get_devices(table), list)
1051                 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1052
1053         param->data_size = param->data_start + needed;
1054 }
1055
1056 static int table_deps(struct dm_ioctl *param, size_t param_size)
1057 {
1058         int r = 0;
1059         struct mapped_device *md;
1060         struct dm_table *table;
1061
1062         md = find_device(param);
1063         if (!md)
1064                 return -ENXIO;
1065
1066         r = __dev_status(md, param);
1067         if (r)
1068                 goto out;
1069
1070         table = dm_get_table(md);
1071         if (table) {
1072                 retrieve_deps(table, param, param_size);
1073                 dm_table_put(table);
1074         }
1075
1076  out:
1077         dm_put(md);
1078         return r;
1079 }
1080
1081 /*
1082  * Return the status of a device as a text string for each
1083  * target.
1084  */
1085 static int table_status(struct dm_ioctl *param, size_t param_size)
1086 {
1087         int r;
1088         struct mapped_device *md;
1089         struct dm_table *table;
1090
1091         md = find_device(param);
1092         if (!md)
1093                 return -ENXIO;
1094
1095         r = __dev_status(md, param);
1096         if (r)
1097                 goto out;
1098
1099         table = dm_get_table(md);
1100         if (table) {
1101                 retrieve_status(table, param, param_size);
1102                 dm_table_put(table);
1103         }
1104
1105  out:
1106         dm_put(md);
1107         return r;
1108 }
1109
1110 /*
1111  * Pass a message to the target that's at the supplied device offset.
1112  */
1113 static int target_message(struct dm_ioctl *param, size_t param_size)
1114 {
1115         int r, argc;
1116         char **argv;
1117         struct mapped_device *md;
1118         struct dm_table *table;
1119         struct dm_target *ti;
1120         struct dm_target_msg *tmsg = (void *) param + param->data_start;
1121
1122         md = find_device(param);
1123         if (!md)
1124                 return -ENXIO;
1125
1126         r = __dev_status(md, param);
1127         if (r)
1128                 goto out;
1129
1130         if (tmsg < (struct dm_target_msg *) (param + 1) ||
1131             invalid_str(tmsg->message, (void *) param + param_size)) {
1132                 DMWARN("Invalid target message parameters.");
1133                 r = -EINVAL;
1134                 goto out;
1135         }
1136
1137         r = dm_split_args(&argc, &argv, tmsg->message);
1138         if (r) {
1139                 DMWARN("Failed to split target message parameters");
1140                 goto out;
1141         }
1142
1143         table = dm_get_table(md);
1144         if (!table)
1145                 goto out_argv;
1146
1147         if (tmsg->sector >= dm_table_get_size(table)) {
1148                 DMWARN("Target message sector outside device.");
1149                 r = -EINVAL;
1150                 goto out_table;
1151         }
1152
1153         ti = dm_table_find_target(table, tmsg->sector);
1154         if (ti->type->message)
1155                 r = ti->type->message(ti, argc, argv);
1156         else {
1157                 DMWARN("Target type does not support messages");
1158                 r = -EINVAL;
1159         }
1160
1161  out_table:
1162         dm_table_put(table);
1163  out_argv:
1164         kfree(argv);
1165  out:
1166         param->data_size = 0;
1167         dm_put(md);
1168         return r;
1169 }
1170
1171 /*-----------------------------------------------------------------
1172  * Implementation of open/close/ioctl on the special char
1173  * device.
1174  *---------------------------------------------------------------*/
1175 static ioctl_fn lookup_ioctl(unsigned int cmd)
1176 {
1177         static struct {
1178                 int cmd;
1179                 ioctl_fn fn;
1180         } _ioctls[] = {
1181                 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1182                 {DM_REMOVE_ALL_CMD, remove_all},
1183                 {DM_LIST_DEVICES_CMD, list_devices},
1184
1185                 {DM_DEV_CREATE_CMD, dev_create},
1186                 {DM_DEV_REMOVE_CMD, dev_remove},
1187                 {DM_DEV_RENAME_CMD, dev_rename},
1188                 {DM_DEV_SUSPEND_CMD, dev_suspend},
1189                 {DM_DEV_STATUS_CMD, dev_status},
1190                 {DM_DEV_WAIT_CMD, dev_wait},
1191
1192                 {DM_TABLE_LOAD_CMD, table_load},
1193                 {DM_TABLE_CLEAR_CMD, table_clear},
1194                 {DM_TABLE_DEPS_CMD, table_deps},
1195                 {DM_TABLE_STATUS_CMD, table_status},
1196
1197                 {DM_LIST_VERSIONS_CMD, list_versions},
1198
1199                 {DM_TARGET_MSG_CMD, target_message}
1200         };
1201
1202         return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1203 }
1204
1205 /*
1206  * As well as checking the version compatibility this always
1207  * copies the kernel interface version out.
1208  */
1209 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1210 {
1211         uint32_t version[3];
1212         int r = 0;
1213
1214         if (copy_from_user(version, user->version, sizeof(version)))
1215                 return -EFAULT;
1216
1217         if ((DM_VERSION_MAJOR != version[0]) ||
1218             (DM_VERSION_MINOR < version[1])) {
1219                 DMWARN("ioctl interface mismatch: "
1220                        "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1221                        DM_VERSION_MAJOR, DM_VERSION_MINOR,
1222                        DM_VERSION_PATCHLEVEL,
1223                        version[0], version[1], version[2], cmd);
1224                 r = -EINVAL;
1225         }
1226
1227         /*
1228          * Fill in the kernel version.
1229          */
1230         version[0] = DM_VERSION_MAJOR;
1231         version[1] = DM_VERSION_MINOR;
1232         version[2] = DM_VERSION_PATCHLEVEL;
1233         if (copy_to_user(user->version, version, sizeof(version)))
1234                 return -EFAULT;
1235
1236         return r;
1237 }
1238
1239 static void free_params(struct dm_ioctl *param)
1240 {
1241         vfree(param);
1242 }
1243
1244 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1245 {
1246         struct dm_ioctl tmp, *dmi;
1247
1248         if (copy_from_user(&tmp, user, sizeof(tmp)))
1249                 return -EFAULT;
1250
1251         if (tmp.data_size < sizeof(tmp))
1252                 return -EINVAL;
1253
1254         dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1255         if (!dmi)
1256                 return -ENOMEM;
1257
1258         if (copy_from_user(dmi, user, tmp.data_size)) {
1259                 vfree(dmi);
1260                 return -EFAULT;
1261         }
1262
1263         *param = dmi;
1264         return 0;
1265 }
1266
1267 static int validate_params(uint cmd, struct dm_ioctl *param)
1268 {
1269         /* Always clear this flag */
1270         param->flags &= ~DM_BUFFER_FULL_FLAG;
1271
1272         /* Ignores parameters */
1273         if (cmd == DM_REMOVE_ALL_CMD ||
1274             cmd == DM_LIST_DEVICES_CMD ||
1275             cmd == DM_LIST_VERSIONS_CMD)
1276                 return 0;
1277
1278         if ((cmd == DM_DEV_CREATE_CMD)) {
1279                 if (!*param->name) {
1280                         DMWARN("name not supplied when creating device");
1281                         return -EINVAL;
1282                 }
1283         } else if ((*param->uuid && *param->name)) {
1284                 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1285                 return -EINVAL;
1286         }
1287
1288         /* Ensure strings are terminated */
1289         param->name[DM_NAME_LEN - 1] = '\0';
1290         param->uuid[DM_UUID_LEN - 1] = '\0';
1291
1292         return 0;
1293 }
1294
1295 static int ctl_ioctl(struct inode *inode, struct file *file,
1296                      uint command, ulong u)
1297 {
1298         int r = 0;
1299         unsigned int cmd;
1300         struct dm_ioctl *param;
1301         struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1302         ioctl_fn fn = NULL;
1303         size_t param_size;
1304
1305         /* only root can play with this */
1306         if (!capable(CAP_SYS_ADMIN))
1307                 return -EACCES;
1308
1309         if (_IOC_TYPE(command) != DM_IOCTL)
1310                 return -ENOTTY;
1311
1312         cmd = _IOC_NR(command);
1313
1314         /*
1315          * Check the interface version passed in.  This also
1316          * writes out the kernel's interface version.
1317          */
1318         r = check_version(cmd, user);
1319         if (r)
1320                 return r;
1321
1322         /*
1323          * Nothing more to do for the version command.
1324          */
1325         if (cmd == DM_VERSION_CMD)
1326                 return 0;
1327
1328         fn = lookup_ioctl(cmd);
1329         if (!fn) {
1330                 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1331                 return -ENOTTY;
1332         }
1333
1334         /*
1335          * Trying to avoid low memory issues when a device is
1336          * suspended.
1337          */
1338         current->flags |= PF_MEMALLOC;
1339
1340         /*
1341          * Copy the parameters into kernel space.
1342          */
1343         r = copy_params(user, &param);
1344         if (r) {
1345                 current->flags &= ~PF_MEMALLOC;
1346                 return r;
1347         }
1348
1349         /*
1350          * FIXME: eventually we will remove the PF_MEMALLOC flag
1351          * here.  However the tools still do nasty things like
1352          * 'load' while a device is suspended.
1353          */
1354
1355         r = validate_params(cmd, param);
1356         if (r)
1357                 goto out;
1358
1359         param_size = param->data_size;
1360         param->data_size = sizeof(*param);
1361         r = fn(param, param_size);
1362
1363         /*
1364          * Copy the results back to userland.
1365          */
1366         if (!r && copy_to_user(user, param, param->data_size))
1367                 r = -EFAULT;
1368
1369  out:
1370         free_params(param);
1371         current->flags &= ~PF_MEMALLOC;
1372         return r;
1373 }
1374
1375 static struct file_operations _ctl_fops = {
1376         .ioctl   = ctl_ioctl,
1377         .owner   = THIS_MODULE,
1378 };
1379
1380 static struct miscdevice _dm_misc = {
1381         .minor          = MISC_DYNAMIC_MINOR,
1382         .name           = DM_NAME,
1383         .devfs_name     = "mapper/control",
1384         .fops           = &_ctl_fops
1385 };
1386
1387 /*
1388  * Create misc character device and link to DM_DIR/control.
1389  */
1390 int __init dm_interface_init(void)
1391 {
1392         int r;
1393
1394         r = dm_hash_init();
1395         if (r)
1396                 return r;
1397
1398         r = misc_register(&_dm_misc);
1399         if (r) {
1400                 DMERR("misc_register failed for control device");
1401                 dm_hash_exit();
1402                 return r;
1403         }
1404
1405         DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1406                DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1407                DM_DRIVER_EMAIL);
1408         return 0;
1409 }
1410
1411 void dm_interface_exit(void)
1412 {
1413         if (misc_deregister(&_dm_misc) < 0)
1414                 DMERR("misc_deregister failed for control device");
1415
1416         dm_hash_exit();
1417 }