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         struct dm_table *table;
 274
 275         /*
 276          * duplicate new.
 277          */
 278         new_name = kstrdup(new, GFP_KERNEL);
 279         if (!new_name)
 280                 return -ENOMEM;
 281
 282         down_write(&_hash_lock);
 283
 284         /*
 285          * Is new free ?
 286          */
 287         hc = __get_name_cell(new);
 288         if (hc) {
 289                 DMWARN("asked to rename to an already existing name %s -> %s",
 290                        old, new);
 291                 up_write(&_hash_lock);
 292                 kfree(new_name);
 293                 return -EBUSY;
 294         }
 295
 296         /*
 297          * Is there such a device as 'old' ?
 298          */
 299         hc = __get_name_cell(old);
 300         if (!hc) {
 301                 DMWARN("asked to rename a non existent device %s -> %s",
 302                        old, new);
 303                 up_write(&_hash_lock);
 304                 kfree(new_name);
 305                 return -ENXIO;
 306         }
 307
 308         /*
 309          * rename and move the name cell.
 310          */
 311         unregister_with_devfs(hc);
 312
 313         list_del(&hc->name_list);
 314         old_name = hc->name;
 315         hc->name = new_name;
 316         list_add(&hc->name_list, _name_buckets + hash_str(new_name));
 317
 318         /* rename the device node in devfs */
 319         register_with_devfs(hc);
 320
 321         /*
 322          * Wake up any dm event waiters.
 323          */
 324         table = dm_get_table(hc->md);
 325         if (table) {
 326                 dm_table_event(table);
 327                 dm_table_put(table);
 328         }
 329
 330         up_write(&_hash_lock);
 331         kfree(old_name);
 332         return 0;
 333 }
 334
 335 /*-----------------------------------------------------------------
 336  * Implementation of the ioctl commands
 337  *---------------------------------------------------------------*/
 338 /*
 339  * All the ioctl commands get dispatched to functions with this
 340  * prototype.
 341  */
 342 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
 343
 344 static int remove_all(struct dm_ioctl *param, size_t param_size)
 345 {
 346         dm_hash_remove_all();
 347         param->data_size = 0;
 348         return 0;
 349 }
 350
 351 /*
 352  * Round up the ptr to an 8-byte boundary.
 353  */
 354 #define ALIGN_MASK 7
 355 static inline void *align_ptr(void *ptr)
 356 {
 357         return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
 358 }
 359
 360 /*
 361  * Retrieves the data payload buffer from an already allocated
 362  * struct dm_ioctl.
 363  */
 364 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
 365                                size_t *len)
 366 {
 367         param->data_start = align_ptr(param + 1) - (void *) param;
 368
 369         if (param->data_start < param_size)
 370                 *len = param_size - param->data_start;
 371         else
 372                 *len = 0;
 373
 374         return ((void *) param) + param->data_start;
 375 }
 376
 377 static int list_devices(struct dm_ioctl *param, size_t param_size)
 378 {
 379         unsigned int i;
 380         struct hash_cell *hc;
 381         size_t len, needed = 0;
 382         struct gendisk *disk;
 383         struct dm_name_list *nl, *old_nl = NULL;
 384
 385         down_write(&_hash_lock);
 386
 387         /*
 388          * Loop through all the devices working out how much
 389          * space we need.
 390          */
 391         for (i = 0; i < NUM_BUCKETS; i++) {
 392                 list_for_each_entry (hc, _name_buckets + i, name_list) {
 393                         needed += sizeof(struct dm_name_list);
 394                         needed += strlen(hc->name) + 1;
 395                         needed += ALIGN_MASK;
 396                 }
 397         }
 398
 399         /*
 400          * Grab our output buffer.
 401          */
 402         nl = get_result_buffer(param, param_size, &len);
 403         if (len < needed) {
 404                 param->flags |= DM_BUFFER_FULL_FLAG;
 405                 goto out;
 406         }
 407         param->data_size = param->data_start + needed;
 408
 409         nl->dev = 0;    /* Flags no data */
 410
 411         /*
 412          * Now loop through filling out the names.
 413          */
 414         for (i = 0; i < NUM_BUCKETS; i++) {
 415                 list_for_each_entry (hc, _name_buckets + i, name_list) {
 416                         if (old_nl)
 417                                 old_nl->next = (uint32_t) ((void *) nl -
 418                                                            (void *) old_nl);
 419                         disk = dm_disk(hc->md);
 420                         nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
 421                         nl->next = 0;
 422                         strcpy(nl->name, hc->name);
 423
 424                         old_nl = nl;
 425                         nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
 426                 }
 427         }
 428
 429  out:
 430         up_write(&_hash_lock);
 431         return 0;
 432 }
 433
 434 static void list_version_get_needed(struct target_type *tt, void *needed_param)
 435 {
 436     size_t *needed = needed_param;
 437
 438     *needed += sizeof(struct dm_target_versions);
 439     *needed += strlen(tt->name);
 440     *needed += ALIGN_MASK;
 441 }
 442
 443 static void list_version_get_info(struct target_type *tt, void *param)
 444 {
 445     struct vers_iter *info = param;
 446
 447     /* Check space - it might have changed since the first iteration */
 448     if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
 449         info->end) {
 450
 451         info->flags = DM_BUFFER_FULL_FLAG;
 452         return;
 453     }
 454
 455     if (info->old_vers)
 456         info->old_vers->next = (uint32_t) ((void *)info->vers -
 457                                            (void *)info->old_vers);
 458     info->vers->version[0] = tt->version[0];
 459     info->vers->version[1] = tt->version[1];
 460     info->vers->version[2] = tt->version[2];
 461     info->vers->next = 0;
 462     strcpy(info->vers->name, tt->name);
 463
 464     info->old_vers = info->vers;
 465     info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
 466 }
 467
 468 static int list_versions(struct dm_ioctl *param, size_t param_size)
 469 {
 470         size_t len, needed = 0;
 471         struct dm_target_versions *vers;
 472         struct vers_iter iter_info;
 473
 474         /*
 475          * Loop through all the devices working out how much
 476          * space we need.
 477          */
 478         dm_target_iterate(list_version_get_needed, &needed);
 479
 480         /*
 481          * Grab our output buffer.
 482          */
 483         vers = get_result_buffer(param, param_size, &len);
 484         if (len < needed) {
 485                 param->flags |= DM_BUFFER_FULL_FLAG;
 486                 goto out;
 487         }
 488         param->data_size = param->data_start + needed;
 489
 490         iter_info.param_size = param_size;
 491         iter_info.old_vers = NULL;
 492         iter_info.vers = vers;
 493         iter_info.flags = 0;
 494         iter_info.end = (char *)vers+len;
 495
 496         /*
 497          * Now loop through filling out the names & versions.
 498          */
 499         dm_target_iterate(list_version_get_info, &iter_info);
 500         param->flags |= iter_info.flags;
 501
 502  out:
 503         return 0;
 504 }
 505
 506
 507
 508 static int check_name(const char *name)
 509 {
 510         if (strchr(name, '/')) {
 511                 DMWARN("invalid device name");
 512                 return -EINVAL;
 513         }
 514
 515         return 0;
 516 }
 517
 518 /*
 519  * Fills in a dm_ioctl structure, ready for sending back to
 520  * userland.
 521  */
 522 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
 523 {
 524         struct gendisk *disk = dm_disk(md);
 525         struct dm_table *table;
 526         struct block_device *bdev;
 527
 528         param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
 529                           DM_ACTIVE_PRESENT_FLAG);
 530
 531         if (dm_suspended(md))
 532                 param->flags |= DM_SUSPEND_FLAG;
 533
 534         param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
 535
 536         if (!(param->flags & DM_SKIP_BDGET_FLAG)) {
 537                 bdev = bdget_disk(disk, 0);
 538                 if (!bdev)
 539                         return -ENXIO;
 540
 541                 /*
 542                  * Yes, this will be out of date by the time it gets back
 543                  * to userland, but it is still very useful for
 544                  * debugging.
 545                  */
 546                 param->open_count = bdev->bd_openers;
 547                 bdput(bdev);
 548         } else
 549                 param->open_count = -1;
 550
 551         if (disk->policy)
 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;
 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                 r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md);
 578         else
 579                 r = dm_create(&md);
 580
 581         if (r)
 582                 return r;
 583
 584         r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
 585         if (r) {
 586                 dm_put(md);
 587                 return r;
 588         }
 589
 590         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 591
 592         r = __dev_status(md, param);
 593         dm_put(md);
 594
 595         return r;
 596 }
 597
 598 /*
 599  * Always use UUID for lookups if it's present, otherwise use name or dev.
 600  */
 601 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
 602 {
 603         struct mapped_device *md;
 604         void *mdptr = NULL;
 605
 606         if (*param->uuid)
 607                 return __get_uuid_cell(param->uuid);
 608
 609         if (*param->name)
 610                 return __get_name_cell(param->name);
 611
 612         md = dm_get_md(huge_decode_dev(param->dev));
 613         if (md) {
 614                 mdptr = dm_get_mdptr(md);
 615                 dm_put(md);
 616         }
 617
 618         return mdptr;
 619 }
 620
 621 static struct mapped_device *find_device(struct dm_ioctl *param)
 622 {
 623         struct hash_cell *hc;
 624         struct mapped_device *md = NULL;
 625
 626         down_read(&_hash_lock);
 627         hc = __find_device_hash_cell(param);
 628         if (hc) {
 629                 md = hc->md;
 630                 dm_get(md);
 631
 632                 /*
 633                  * Sneakily write in both the name and the uuid
 634                  * while we have the cell.
 635                  */
 636                 strncpy(param->name, hc->name, sizeof(param->name));
 637                 if (hc->uuid)
 638                         strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
 639                 else
 640                         param->uuid[0] = '\0';
 641
 642                 if (hc->new_map)
 643                         param->flags |= DM_INACTIVE_PRESENT_FLAG;
 644                 else
 645                         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 646         }
 647         up_read(&_hash_lock);
 648
 649         return md;
 650 }
 651
 652 static int dev_remove(struct dm_ioctl *param, size_t param_size)
 653 {
 654         struct hash_cell *hc;
 655
 656         down_write(&_hash_lock);
 657         hc = __find_device_hash_cell(param);
 658
 659         if (!hc) {
 660                 DMWARN("device doesn't appear to be in the dev hash table.");
 661                 up_write(&_hash_lock);
 662                 return -ENXIO;
 663         }
 664
 665         __hash_remove(hc);
 666         up_write(&_hash_lock);
 667         param->data_size = 0;
 668         return 0;
 669 }
 670
 671 /*
 672  * Check a string doesn't overrun the chunk of
 673  * memory we copied from userland.
 674  */
 675 static int invalid_str(char *str, void *end)
 676 {
 677         while ((void *) str < end)
 678                 if (!*str++)
 679                         return 0;
 680
 681         return -EINVAL;
 682 }
 683
 684 static int dev_rename(struct dm_ioctl *param, size_t param_size)
 685 {
 686         int r;
 687         char *new_name = (char *) param + param->data_start;
 688
 689         if (new_name < (char *) (param + 1) ||
 690             invalid_str(new_name, (void *) param + param_size)) {
 691                 DMWARN("Invalid new logical volume name supplied.");
 692                 return -EINVAL;
 693         }
 694
 695         r = check_name(new_name);
 696         if (r)
 697                 return r;
 698
 699         param->data_size = 0;
 700         return dm_hash_rename(param->name, new_name);
 701 }
 702
 703 static int do_suspend(struct dm_ioctl *param)
 704 {
 705         int r = 0;
 706         int do_lockfs = 1;
 707         struct mapped_device *md;
 708
 709         md = find_device(param);
 710         if (!md)
 711                 return -ENXIO;
 712
 713         if (param->flags & DM_SKIP_LOCKFS_FLAG)
 714                 do_lockfs = 0;
 715
 716         if (!dm_suspended(md))
 717                 r = dm_suspend(md, do_lockfs);
 718
 719         if (!r)
 720                 r = __dev_status(md, param);
 721
 722         dm_put(md);
 723         return r;
 724 }
 725
 726 static int do_resume(struct dm_ioctl *param)
 727 {
 728         int r = 0;
 729         int do_lockfs = 1;
 730         struct hash_cell *hc;
 731         struct mapped_device *md;
 732         struct dm_table *new_map;
 733
 734         down_write(&_hash_lock);
 735
 736         hc = __find_device_hash_cell(param);
 737         if (!hc) {
 738                 DMWARN("device doesn't appear to be in the dev hash table.");
 739                 up_write(&_hash_lock);
 740                 return -ENXIO;
 741         }
 742
 743         md = hc->md;
 744         dm_get(md);
 745
 746         new_map = hc->new_map;
 747         hc->new_map = NULL;
 748         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
 749
 750         up_write(&_hash_lock);
 751
 752         /* Do we need to load a new map ? */
 753         if (new_map) {
 754                 /* Suspend if it isn't already suspended */
 755                 if (param->flags & DM_SKIP_LOCKFS_FLAG)
 756                         do_lockfs = 0;
 757                 if (!dm_suspended(md))
 758                         dm_suspend(md, do_lockfs);
 759
 760                 r = dm_swap_table(md, new_map);
 761                 if (r) {
 762                         dm_put(md);
 763                         dm_table_put(new_map);
 764                         return r;
 765                 }
 766
 767                 if (dm_table_get_mode(new_map) & FMODE_WRITE)
 768                         set_disk_ro(dm_disk(md), 0);
 769                 else
 770                         set_disk_ro(dm_disk(md), 1);
 771
 772                 dm_table_put(new_map);
 773         }
 774
 775         if (dm_suspended(md))
 776                 r = dm_resume(md);
 777
 778         if (!r)
 779                 r = __dev_status(md, param);
 780
 781         dm_put(md);
 782         return r;
 783 }
 784
 785 /*
 786  * Set or unset the suspension state of a device.
 787  * If the device already is in the requested state we just return its status.
 788  */
 789 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
 790 {
 791         if (param->flags & DM_SUSPEND_FLAG)
 792                 return do_suspend(param);
 793
 794         return do_resume(param);
 795 }
 796
 797 /*
 798  * Copies device info back to user space, used by
 799  * the create and info ioctls.
 800  */
 801 static int dev_status(struct dm_ioctl *param, size_t param_size)
 802 {
 803         int r;
 804         struct mapped_device *md;
 805
 806         md = find_device(param);
 807         if (!md)
 808                 return -ENXIO;
 809
 810         r = __dev_status(md, param);
 811         dm_put(md);
 812         return r;
 813 }
 814
 815 /*
 816  * Build up the status struct for each target
 817  */
 818 static void retrieve_status(struct dm_table *table,
 819                             struct dm_ioctl *param, size_t param_size)
 820 {
 821         unsigned int i, num_targets;
 822         struct dm_target_spec *spec;
 823         char *outbuf, *outptr;
 824         status_type_t type;
 825         size_t remaining, len, used = 0;
 826
 827         outptr = outbuf = get_result_buffer(param, param_size, &len);
 828
 829         if (param->flags & DM_STATUS_TABLE_FLAG)
 830                 type = STATUSTYPE_TABLE;
 831         else
 832                 type = STATUSTYPE_INFO;
 833
 834         /* Get all the target info */
 835         num_targets = dm_table_get_num_targets(table);
 836         for (i = 0; i < num_targets; i++) {
 837                 struct dm_target *ti = dm_table_get_target(table, i);
 838
 839                 remaining = len - (outptr - outbuf);
 840                 if (remaining <= sizeof(struct dm_target_spec)) {
 841                         param->flags |= DM_BUFFER_FULL_FLAG;
 842                         break;
 843                 }
 844
 845                 spec = (struct dm_target_spec *) outptr;
 846
 847                 spec->status = 0;
 848                 spec->sector_start = ti->begin;
 849                 spec->length = ti->len;
 850                 strncpy(spec->target_type, ti->type->name,
 851                         sizeof(spec->target_type));
 852
 853                 outptr += sizeof(struct dm_target_spec);
 854                 remaining = len - (outptr - outbuf);
 855                 if (remaining <= 0) {
 856                         param->flags |= DM_BUFFER_FULL_FLAG;
 857                         break;
 858                 }
 859
 860                 /* Get the status/table string from the target driver */
 861                 if (ti->type->status) {
 862                         if (ti->type->status(ti, type, outptr, remaining)) {
 863                                 param->flags |= DM_BUFFER_FULL_FLAG;
 864                                 break;
 865                         }
 866                 } else
 867                         outptr[0] = '\0';
 868
 869                 outptr += strlen(outptr) + 1;
 870                 used = param->data_start + (outptr - outbuf);
 871
 872                 outptr = align_ptr(outptr);
 873                 spec->next = outptr - outbuf;
 874         }
 875
 876         if (used)
 877                 param->data_size = used;
 878
 879         param->target_count = num_targets;
 880 }
 881
 882 /*
 883  * Wait for a device to report an event
 884  */
 885 static int dev_wait(struct dm_ioctl *param, size_t param_size)
 886 {
 887         int r;
 888         struct mapped_device *md;
 889         struct dm_table *table;
 890
 891         md = find_device(param);
 892         if (!md)
 893                 return -ENXIO;
 894
 895         /*
 896          * Wait for a notification event
 897          */
 898         if (dm_wait_event(md, param->event_nr)) {
 899                 r = -ERESTARTSYS;
 900                 goto out;
 901         }
 902
 903         /*
 904          * The userland program is going to want to know what
 905          * changed to trigger the event, so we may as well tell
 906          * him and save an ioctl.
 907          */
 908         r = __dev_status(md, param);
 909         if (r)
 910                 goto out;
 911
 912         table = dm_get_table(md);
 913         if (table) {
 914                 retrieve_status(table, param, param_size);
 915                 dm_table_put(table);
 916         }
 917
 918  out:
 919         dm_put(md);
 920         return r;
 921 }
 922
 923 static inline int get_mode(struct dm_ioctl *param)
 924 {
 925         int mode = FMODE_READ | FMODE_WRITE;
 926
 927         if (param->flags & DM_READONLY_FLAG)
 928                 mode = FMODE_READ;
 929
 930         return mode;
 931 }
 932
 933 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
 934                        struct dm_target_spec **spec, char **target_params)
 935 {
 936         *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
 937         *target_params = (char *) (*spec + 1);
 938
 939         if (*spec < (last + 1))
 940                 return -EINVAL;
 941
 942         return invalid_str(*target_params, end);
 943 }
 944
 945 static int populate_table(struct dm_table *table,
 946                           struct dm_ioctl *param, size_t param_size)
 947 {
 948         int r;
 949         unsigned int i = 0;
 950         struct dm_target_spec *spec = (struct dm_target_spec *) param;
 951         uint32_t next = param->data_start;
 952         void *end = (void *) param + param_size;
 953         char *target_params;
 954
 955         if (!param->target_count) {
 956                 DMWARN("populate_table: no targets specified");
 957                 return -EINVAL;
 958         }
 959
 960         for (i = 0; i < param->target_count; i++) {
 961
 962                 r = next_target(spec, next, end, &spec, &target_params);
 963                 if (r) {
 964                         DMWARN("unable to find target");
 965                         return r;
 966                 }
 967
 968                 r = dm_table_add_target(table, spec->target_type,
 969                                         (sector_t) spec->sector_start,
 970                                         (sector_t) spec->length,
 971                                         target_params);
 972                 if (r) {
 973                         DMWARN("error adding target to table");
 974                         return r;
 975                 }
 976
 977                 next = spec->next;
 978         }
 979
 980         return dm_table_complete(table);
 981 }
 982
 983 static int table_load(struct dm_ioctl *param, size_t param_size)
 984 {
 985         int r;
 986         struct hash_cell *hc;
 987         struct dm_table *t;
 988
 989         r = dm_table_create(&t, get_mode(param), param->target_count);
 990         if (r)
 991                 return r;
 992
 993         r = populate_table(t, param, param_size);
 994         if (r) {
 995                 dm_table_put(t);
 996                 return r;
 997         }
 998
 999         down_write(&_hash_lock);
1000         hc = __find_device_hash_cell(param);
1001         if (!hc) {
1002                 DMWARN("device doesn't appear to be in the dev hash table.");
1003                 up_write(&_hash_lock);
1004                 dm_table_put(t);
1005                 return -ENXIO;
1006         }
1007
1008         if (hc->new_map)
1009                 dm_table_put(hc->new_map);
1010         hc->new_map = t;
1011         param->flags |= DM_INACTIVE_PRESENT_FLAG;
1012
1013         r = __dev_status(hc->md, param);
1014         up_write(&_hash_lock);
1015         return r;
1016 }
1017
1018 static int table_clear(struct dm_ioctl *param, size_t param_size)
1019 {
1020         int r;
1021         struct hash_cell *hc;
1022
1023         down_write(&_hash_lock);
1024
1025         hc = __find_device_hash_cell(param);
1026         if (!hc) {
1027                 DMWARN("device doesn't appear to be in the dev hash table.");
1028                 up_write(&_hash_lock);
1029                 return -ENXIO;
1030         }
1031
1032         if (hc->new_map) {
1033                 dm_table_put(hc->new_map);
1034                 hc->new_map = NULL;
1035         }
1036
1037         param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1038
1039         r = __dev_status(hc->md, param);
1040         up_write(&_hash_lock);
1041         return r;
1042 }
1043
1044 /*
1045  * Retrieves a list of devices used by a particular dm device.
1046  */
1047 static void retrieve_deps(struct dm_table *table,
1048                           struct dm_ioctl *param, size_t param_size)
1049 {
1050         unsigned int count = 0;
1051         struct list_head *tmp;
1052         size_t len, needed;
1053         struct dm_dev *dd;
1054         struct dm_target_deps *deps;
1055
1056         deps = get_result_buffer(param, param_size, &len);
1057
1058         /*
1059          * Count the devices.
1060          */
1061         list_for_each (tmp, dm_table_get_devices(table))
1062                 count++;
1063
1064         /*
1065          * Check we have enough space.
1066          */
1067         needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1068         if (len < needed) {
1069                 param->flags |= DM_BUFFER_FULL_FLAG;
1070                 return;
1071         }
1072
1073         /*
1074          * Fill in the devices.
1075          */
1076         deps->count = count;
1077         count = 0;
1078         list_for_each_entry (dd, dm_table_get_devices(table), list)
1079                 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1080
1081         param->data_size = param->data_start + needed;
1082 }
1083
1084 static int table_deps(struct dm_ioctl *param, size_t param_size)
1085 {
1086         int r = 0;
1087         struct mapped_device *md;
1088         struct dm_table *table;
1089
1090         md = find_device(param);
1091         if (!md)
1092                 return -ENXIO;
1093
1094         r = __dev_status(md, param);
1095         if (r)
1096                 goto out;
1097
1098         table = dm_get_table(md);
1099         if (table) {
1100                 retrieve_deps(table, param, param_size);
1101                 dm_table_put(table);
1102         }
1103
1104  out:
1105         dm_put(md);
1106         return r;
1107 }
1108
1109 /*
1110  * Return the status of a device as a text string for each
1111  * target.
1112  */
1113 static int table_status(struct dm_ioctl *param, size_t param_size)
1114 {
1115         int r;
1116         struct mapped_device *md;
1117         struct dm_table *table;
1118
1119         md = find_device(param);
1120         if (!md)
1121                 return -ENXIO;
1122
1123         r = __dev_status(md, param);
1124         if (r)
1125                 goto out;
1126
1127         table = dm_get_table(md);
1128         if (table) {
1129                 retrieve_status(table, param, param_size);
1130                 dm_table_put(table);
1131         }
1132
1133  out:
1134         dm_put(md);
1135         return r;
1136 }
1137
1138 /*
1139  * Pass a message to the target that's at the supplied device offset.
1140  */
1141 static int target_message(struct dm_ioctl *param, size_t param_size)
1142 {
1143         int r, argc;
1144         char **argv;
1145         struct mapped_device *md;
1146         struct dm_table *table;
1147         struct dm_target *ti;
1148         struct dm_target_msg *tmsg = (void *) param + param->data_start;
1149
1150         md = find_device(param);
1151         if (!md)
1152                 return -ENXIO;
1153
1154         r = __dev_status(md, param);
1155         if (r)
1156                 goto out;
1157
1158         if (tmsg < (struct dm_target_msg *) (param + 1) ||
1159             invalid_str(tmsg->message, (void *) param + param_size)) {
1160                 DMWARN("Invalid target message parameters.");
1161                 r = -EINVAL;
1162                 goto out;
1163         }
1164
1165         r = dm_split_args(&argc, &argv, tmsg->message);
1166         if (r) {
1167                 DMWARN("Failed to split target message parameters");
1168                 goto out;
1169         }
1170
1171         table = dm_get_table(md);
1172         if (!table)
1173                 goto out_argv;
1174
1175         if (tmsg->sector >= dm_table_get_size(table)) {
1176                 DMWARN("Target message sector outside device.");
1177                 r = -EINVAL;
1178                 goto out_table;
1179         }
1180
1181         ti = dm_table_find_target(table, tmsg->sector);
1182         if (ti->type->message)
1183                 r = ti->type->message(ti, argc, argv);
1184         else {
1185                 DMWARN("Target type does not support messages");
1186                 r = -EINVAL;
1187         }
1188
1189  out_table:
1190         dm_table_put(table);
1191  out_argv:
1192         kfree(argv);
1193  out:
1194         param->data_size = 0;
1195         dm_put(md);
1196         return r;
1197 }
1198
1199 /*-----------------------------------------------------------------
1200  * Implementation of open/close/ioctl on the special char
1201  * device.
1202  *---------------------------------------------------------------*/
1203 static ioctl_fn lookup_ioctl(unsigned int cmd)
1204 {
1205         static struct {
1206                 int cmd;
1207                 ioctl_fn fn;
1208         } _ioctls[] = {
1209                 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1210                 {DM_REMOVE_ALL_CMD, remove_all},
1211                 {DM_LIST_DEVICES_CMD, list_devices},
1212
1213                 {DM_DEV_CREATE_CMD, dev_create},
1214                 {DM_DEV_REMOVE_CMD, dev_remove},
1215                 {DM_DEV_RENAME_CMD, dev_rename},
1216                 {DM_DEV_SUSPEND_CMD, dev_suspend},
1217                 {DM_DEV_STATUS_CMD, dev_status},
1218                 {DM_DEV_WAIT_CMD, dev_wait},
1219
1220                 {DM_TABLE_LOAD_CMD, table_load},
1221                 {DM_TABLE_CLEAR_CMD, table_clear},
1222                 {DM_TABLE_DEPS_CMD, table_deps},
1223                 {DM_TABLE_STATUS_CMD, table_status},
1224
1225                 {DM_LIST_VERSIONS_CMD, list_versions},
1226
1227                 {DM_TARGET_MSG_CMD, target_message}
1228         };
1229
1230         return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1231 }
1232
1233 /*
1234  * As well as checking the version compatibility this always
1235  * copies the kernel interface version out.
1236  */
1237 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1238 {
1239         uint32_t version[3];
1240         int r = 0;
1241
1242         if (copy_from_user(version, user->version, sizeof(version)))
1243                 return -EFAULT;
1244
1245         if ((DM_VERSION_MAJOR != version[0]) ||
1246             (DM_VERSION_MINOR < version[1])) {
1247                 DMWARN("ioctl interface mismatch: "
1248                        "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1249                        DM_VERSION_MAJOR, DM_VERSION_MINOR,
1250                        DM_VERSION_PATCHLEVEL,
1251                        version[0], version[1], version[2], cmd);
1252                 r = -EINVAL;
1253         }
1254
1255         /*
1256          * Fill in the kernel version.
1257          */
1258         version[0] = DM_VERSION_MAJOR;
1259         version[1] = DM_VERSION_MINOR;
1260         version[2] = DM_VERSION_PATCHLEVEL;
1261         if (copy_to_user(user->version, version, sizeof(version)))
1262                 return -EFAULT;
1263
1264         return r;
1265 }
1266
1267 static void free_params(struct dm_ioctl *param)
1268 {
1269         vfree(param);
1270 }
1271
1272 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1273 {
1274         struct dm_ioctl tmp, *dmi;
1275
1276         if (copy_from_user(&tmp, user, sizeof(tmp)))
1277                 return -EFAULT;
1278
1279         if (tmp.data_size < sizeof(tmp))
1280                 return -EINVAL;
1281
1282         dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1283         if (!dmi)
1284                 return -ENOMEM;
1285
1286         if (copy_from_user(dmi, user, tmp.data_size)) {
1287                 vfree(dmi);
1288                 return -EFAULT;
1289         }
1290
1291         *param = dmi;
1292         return 0;
1293 }
1294
1295 static int validate_params(uint cmd, struct dm_ioctl *param)
1296 {
1297         /* Always clear this flag */
1298         param->flags &= ~DM_BUFFER_FULL_FLAG;
1299
1300         /* Ignores parameters */
1301         if (cmd == DM_REMOVE_ALL_CMD ||
1302             cmd == DM_LIST_DEVICES_CMD ||
1303             cmd == DM_LIST_VERSIONS_CMD)
1304                 return 0;
1305
1306         if ((cmd == DM_DEV_CREATE_CMD)) {
1307                 if (!*param->name) {
1308                         DMWARN("name not supplied when creating device");
1309                         return -EINVAL;
1310                 }
1311         } else if ((*param->uuid && *param->name)) {
1312                 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1313                 return -EINVAL;
1314         }
1315
1316         /* Ensure strings are terminated */
1317         param->name[DM_NAME_LEN - 1] = '\0';
1318         param->uuid[DM_UUID_LEN - 1] = '\0';
1319
1320         return 0;
1321 }
1322
1323 static int ctl_ioctl(struct inode *inode, struct file *file,
1324                      uint command, ulong u)
1325 {
1326         int r = 0;
1327         unsigned int cmd;
1328         struct dm_ioctl *param;
1329         struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1330         ioctl_fn fn = NULL;
1331         size_t param_size;
1332
1333         /* only root can play with this */
1334         if (!capable(CAP_SYS_ADMIN))
1335                 return -EACCES;
1336
1337         if (_IOC_TYPE(command) != DM_IOCTL)
1338                 return -ENOTTY;
1339
1340         cmd = _IOC_NR(command);
1341
1342         /*
1343          * Check the interface version passed in.  This also
1344          * writes out the kernel's interface version.
1345          */
1346         r = check_version(cmd, user);
1347         if (r)
1348                 return r;
1349
1350         /*
1351          * Nothing more to do for the version command.
1352          */
1353         if (cmd == DM_VERSION_CMD)
1354                 return 0;
1355
1356         fn = lookup_ioctl(cmd);
1357         if (!fn) {
1358                 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1359                 return -ENOTTY;
1360         }
1361
1362         /*
1363          * Trying to avoid low memory issues when a device is
1364          * suspended.
1365          */
1366         current->flags |= PF_MEMALLOC;
1367
1368         /*
1369          * Copy the parameters into kernel space.
1370          */
1371         r = copy_params(user, &param);
1372
1373         current->flags &= ~PF_MEMALLOC;
1374
1375         if (r)
1376                 return r;
1377
1378         r = validate_params(cmd, param);
1379         if (r)
1380                 goto out;
1381
1382         param_size = param->data_size;
1383         param->data_size = sizeof(*param);
1384         r = fn(param, param_size);
1385
1386         /*
1387          * Copy the results back to userland.
1388          */
1389         if (!r && copy_to_user(user, param, param->data_size))
1390                 r = -EFAULT;
1391
1392  out:
1393         free_params(param);
1394         return r;
1395 }
1396
1397 static struct file_operations _ctl_fops = {
1398         .ioctl   = ctl_ioctl,
1399         .owner   = THIS_MODULE,
1400 };
1401
1402 static struct miscdevice _dm_misc = {
1403         .minor          = MISC_DYNAMIC_MINOR,
1404         .name           = DM_NAME,
1405         .devfs_name     = "mapper/control",
1406         .fops           = &_ctl_fops
1407 };
1408
1409 /*
1410  * Create misc character device and link to DM_DIR/control.
1411  */
1412 int __init dm_interface_init(void)
1413 {
1414         int r;
1415
1416         r = dm_hash_init();
1417         if (r)
1418                 return r;
1419
1420         r = misc_register(&_dm_misc);
1421         if (r) {
1422                 DMERR("misc_register failed for control device");
1423                 dm_hash_exit();
1424                 return r;
1425         }
1426
1427         DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1428                DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1429                DM_DRIVER_EMAIL);
1430         return 0;
1431 }
1432
1433 void dm_interface_exit(void)
1434 {
1435         if (misc_deregister(&_dm_misc) < 0)
1436                 DMERR("misc_deregister failed for control device");
1437
1438         dm_hash_exit();
1439 }