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   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  12  * the GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Author: Artem Bityutskiy (Битюцкий Артём)
  19  */
  20
  21 /*
  22  * This file includes implementation of UBI character device operations.
  23  *
  24  * There are two kinds of character devices in UBI: UBI character devices and
  25  * UBI volume character devices. UBI character devices allow users to
  26  * manipulate whole volumes: create, remove, and re-size them. Volume character
  27  * devices provide volume I/O capabilities.
  28  *
  29  * Major and minor numbers are assigned dynamically to both UBI and volume
  30  * character devices.
  31  *
  32  * Well, there is the third kind of character devices - the UBI control
  33  * character device, which allows to manipulate by UBI devices - create and
  34  * delete them. In other words, it is used for attaching and detaching MTD
  35  * devices.
  36  */
  37
  38 #include <linux/module.h>
  39 #include <linux/stat.h>
  40 #include <linux/slab.h>
  41 #include <linux/ioctl.h>
  42 #include <linux/capability.h>
  43 #include <linux/uaccess.h>
  44 #include <linux/compat.h>
  45 #include <linux/math64.h>
  46 #include <mtd/ubi-user.h>
  47 #include "ubi.h"
  48
  49 /**
  50  * get_exclusive - get exclusive access to an UBI volume.
  51  * @desc: volume descriptor
  52  *
  53  * This function changes UBI volume open mode to "exclusive". Returns previous
  54  * mode value (positive integer) in case of success and a negative error code
  55  * in case of failure.
  56  */
  57 static int get_exclusive(struct ubi_volume_desc *desc)
  58 {
  59         int users, err;
  60         struct ubi_volume *vol = desc->vol;
  61
  62         spin_lock(&vol->ubi->volumes_lock);
  63         users = vol->readers + vol->writers + vol->exclusive;
  64         ubi_assert(users > 0);
  65         if (users > 1) {
  66                 dbg_err("%d users for volume %d", users, vol->vol_id);
  67                 err = -EBUSY;
  68         } else {
  69                 vol->readers = vol->writers = 0;
  70                 vol->exclusive = 1;
  71                 err = desc->mode;
  72                 desc->mode = UBI_EXCLUSIVE;
  73         }
  74         spin_unlock(&vol->ubi->volumes_lock);
  75
  76         return err;
  77 }
  78
  79 /**
  80  * revoke_exclusive - revoke exclusive mode.
  81  * @desc: volume descriptor
  82  * @mode: new mode to switch to
  83  */
  84 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
  85 {
  86         struct ubi_volume *vol = desc->vol;
  87
  88         spin_lock(&vol->ubi->volumes_lock);
  89         ubi_assert(vol->readers == 0 && vol->writers == 0);
  90         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
  91         vol->exclusive = 0;
  92         if (mode == UBI_READONLY)
  93                 vol->readers = 1;
  94         else if (mode == UBI_READWRITE)
  95                 vol->writers = 1;
  96         else
  97                 vol->exclusive = 1;
  98         spin_unlock(&vol->ubi->volumes_lock);
  99
 100         desc->mode = mode;
 101 }
 102
 103 static int vol_cdev_open(struct inode *inode, struct file *file)
 104 {
 105         struct ubi_volume_desc *desc;
 106         int vol_id = iminor(inode) - 1, mode, ubi_num;
 107
 108         ubi_num = ubi_major2num(imajor(inode));
 109         if (ubi_num < 0)
 110                 return ubi_num;
 111
 112         if (file->f_mode & FMODE_WRITE)
 113                 mode = UBI_READWRITE;
 114         else
 115                 mode = UBI_READONLY;
 116
 117         dbg_gen("open device %d, volume %d, mode %d",
 118                 ubi_num, vol_id, mode);
 119
 120         desc = ubi_open_volume(ubi_num, vol_id, mode);
 121         if (IS_ERR(desc))
 122                 return PTR_ERR(desc);
 123
 124         file->private_data = desc;
 125         return 0;
 126 }
 127
 128 static int vol_cdev_release(struct inode *inode, struct file *file)
 129 {
 130         struct ubi_volume_desc *desc = file->private_data;
 131         struct ubi_volume *vol = desc->vol;
 132
 133         dbg_gen("release device %d, volume %d, mode %d",
 134                 vol->ubi->ubi_num, vol->vol_id, desc->mode);
 135
 136         if (vol->updating) {
 137                 ubi_warn("update of volume %d not finished, volume is damaged",
 138                          vol->vol_id);
 139                 ubi_assert(!vol->changing_leb);
 140                 vol->updating = 0;
 141                 vfree(vol->upd_buf);
 142         } else if (vol->changing_leb) {
 143                 dbg_gen("only %lld of %lld bytes received for atomic LEB change"
 144                         " for volume %d:%d, cancel", vol->upd_received,
 145                         vol->upd_bytes, vol->ubi->ubi_num, vol->vol_id);
 146                 vol->changing_leb = 0;
 147                 vfree(vol->upd_buf);
 148         }
 149
 150         ubi_close_volume(desc);
 151         return 0;
 152 }
 153
 154 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
 155 {
 156         struct ubi_volume_desc *desc = file->private_data;
 157         struct ubi_volume *vol = desc->vol;
 158         loff_t new_offset;
 159
 160         if (vol->updating) {
 161                  /* Update is in progress, seeking is prohibited */
 162                 dbg_err("updating");
 163                 return -EBUSY;
 164         }
 165
 166         switch (origin) {
 167         case 0: /* SEEK_SET */
 168                 new_offset = offset;
 169                 break;
 170         case 1: /* SEEK_CUR */
 171                 new_offset = file->f_pos + offset;
 172                 break;
 173         case 2: /* SEEK_END */
 174                 new_offset = vol->used_bytes + offset;
 175                 break;
 176         default:
 177                 return -EINVAL;
 178         }
 179
 180         if (new_offset < 0 || new_offset > vol->used_bytes) {
 181                 dbg_err("bad seek %lld", new_offset);
 182                 return -EINVAL;
 183         }
 184
 185         dbg_gen("seek volume %d, offset %lld, origin %d, new offset %lld",
 186                 vol->vol_id, offset, origin, new_offset);
 187
 188         file->f_pos = new_offset;
 189         return new_offset;
 190 }
 191
 192 static int vol_cdev_fsync(struct file *file, struct dentry *dentry,
 193                           int datasync)
 194 {
 195         struct ubi_volume_desc *desc = file->private_data;
 196         struct ubi_device *ubi = desc->vol->ubi;
 197
 198         return ubi_sync(ubi->ubi_num);
 199 }
 200
 201
 202 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 203                              loff_t *offp)
 204 {
 205         struct ubi_volume_desc *desc = file->private_data;
 206         struct ubi_volume *vol = desc->vol;
 207         struct ubi_device *ubi = vol->ubi;
 208         int err, lnum, off, len,  tbuf_size;
 209         size_t count_save = count;
 210         void *tbuf;
 211
 212         dbg_gen("read %zd bytes from offset %lld of volume %d",
 213                 count, *offp, vol->vol_id);
 214
 215         if (vol->updating) {
 216                 dbg_err("updating");
 217                 return -EBUSY;
 218         }
 219         if (vol->upd_marker) {
 220                 dbg_err("damaged volume, update marker is set");
 221                 return -EBADF;
 222         }
 223         if (*offp == vol->used_bytes || count == 0)
 224                 return 0;
 225
 226         if (vol->corrupted)
 227                 dbg_gen("read from corrupted volume %d", vol->vol_id);
 228
 229         if (*offp + count > vol->used_bytes)
 230                 count_save = count = vol->used_bytes - *offp;
 231
 232         tbuf_size = vol->usable_leb_size;
 233         if (count < tbuf_size)
 234                 tbuf_size = ALIGN(count, ubi->min_io_size);
 235         tbuf = vmalloc(tbuf_size);
 236         if (!tbuf)
 237                 return -ENOMEM;
 238
 239         len = count > tbuf_size ? tbuf_size : count;
 240         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 241
 242         do {
 243                 cond_resched();
 244
 245                 if (off + len >= vol->usable_leb_size)
 246                         len = vol->usable_leb_size - off;
 247
 248                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
 249                 if (err)
 250                         break;
 251
 252                 off += len;
 253                 if (off == vol->usable_leb_size) {
 254                         lnum += 1;
 255                         off -= vol->usable_leb_size;
 256                 }
 257
 258                 count -= len;
 259                 *offp += len;
 260
 261                 err = copy_to_user(buf, tbuf, len);
 262                 if (err) {
 263                         err = -EFAULT;
 264                         break;
 265                 }
 266
 267                 buf += len;
 268                 len = count > tbuf_size ? tbuf_size : count;
 269         } while (count);
 270
 271         vfree(tbuf);
 272         return err ? err : count_save - count;
 273 }
 274
 275 /*
 276  * This function allows to directly write to dynamic UBI volumes, without
 277  * issuing the volume update operation.
 278  */
 279 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 280                                      size_t count, loff_t *offp)
 281 {
 282         struct ubi_volume_desc *desc = file->private_data;
 283         struct ubi_volume *vol = desc->vol;
 284         struct ubi_device *ubi = vol->ubi;
 285         int lnum, off, len, tbuf_size, err = 0;
 286         size_t count_save = count;
 287         char *tbuf;
 288
 289         if (!vol->direct_writes)
 290                 return -EPERM;
 291
 292         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
 293                 count, *offp, vol->vol_id);
 294
 295         if (vol->vol_type == UBI_STATIC_VOLUME)
 296                 return -EROFS;
 297
 298         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 299         if (off & (ubi->min_io_size - 1)) {
 300                 dbg_err("unaligned position");
 301                 return -EINVAL;
 302         }
 303
 304         if (*offp + count > vol->used_bytes)
 305                 count_save = count = vol->used_bytes - *offp;
 306
 307         /* We can write only in fractions of the minimum I/O unit */
 308         if (count & (ubi->min_io_size - 1)) {
 309                 dbg_err("unaligned write length");
 310                 return -EINVAL;
 311         }
 312
 313         tbuf_size = vol->usable_leb_size;
 314         if (count < tbuf_size)
 315                 tbuf_size = ALIGN(count, ubi->min_io_size);
 316         tbuf = vmalloc(tbuf_size);
 317         if (!tbuf)
 318                 return -ENOMEM;
 319
 320         len = count > tbuf_size ? tbuf_size : count;
 321
 322         while (count) {
 323                 cond_resched();
 324
 325                 if (off + len >= vol->usable_leb_size)
 326                         len = vol->usable_leb_size - off;
 327
 328                 err = copy_from_user(tbuf, buf, len);
 329                 if (err) {
 330                         err = -EFAULT;
 331                         break;
 332                 }
 333
 334                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
 335                                         UBI_UNKNOWN);
 336                 if (err)
 337                         break;
 338
 339                 off += len;
 340                 if (off == vol->usable_leb_size) {
 341                         lnum += 1;
 342                         off -= vol->usable_leb_size;
 343                 }
 344
 345                 count -= len;
 346                 *offp += len;
 347                 buf += len;
 348                 len = count > tbuf_size ? tbuf_size : count;
 349         }
 350
 351         vfree(tbuf);
 352         return err ? err : count_save - count;
 353 }
 354
 355 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 356                               size_t count, loff_t *offp)
 357 {
 358         int err = 0;
 359         struct ubi_volume_desc *desc = file->private_data;
 360         struct ubi_volume *vol = desc->vol;
 361         struct ubi_device *ubi = vol->ubi;
 362
 363         if (!vol->updating && !vol->changing_leb)
 364                 return vol_cdev_direct_write(file, buf, count, offp);
 365
 366         if (vol->updating)
 367                 err = ubi_more_update_data(ubi, vol, buf, count);
 368         else
 369                 err = ubi_more_leb_change_data(ubi, vol, buf, count);
 370
 371         if (err < 0) {
 372                 ubi_err("cannot accept more %zd bytes of data, error %d",
 373                         count, err);
 374                 return err;
 375         }
 376
 377         if (err) {
 378                 /*
 379                  * The operation is finished, @err contains number of actually
 380                  * written bytes.
 381                  */
 382                 count = err;
 383
 384                 if (vol->changing_leb) {
 385                         revoke_exclusive(desc, UBI_READWRITE);
 386                         return count;
 387                 }
 388
 389                 err = ubi_check_volume(ubi, vol->vol_id);
 390                 if (err < 0)
 391                         return err;
 392
 393                 if (err) {
 394                         ubi_warn("volume %d on UBI device %d is corrupted",
 395                                  vol->vol_id, ubi->ubi_num);
 396                         vol->corrupted = 1;
 397                 }
 398                 vol->checked = 1;
 399                 ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
 400                 revoke_exclusive(desc, UBI_READWRITE);
 401         }
 402
 403         return count;
 404 }
 405
 406 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
 407                            unsigned long arg)
 408 {
 409         int err = 0;
 410         struct ubi_volume_desc *desc = file->private_data;
 411         struct ubi_volume *vol = desc->vol;
 412         struct ubi_device *ubi = vol->ubi;
 413         void __user *argp = (void __user *)arg;
 414
 415         switch (cmd) {
 416         /* Volume update command */
 417         case UBI_IOCVOLUP:
 418         {
 419                 int64_t bytes, rsvd_bytes;
 420
 421                 if (!capable(CAP_SYS_RESOURCE)) {
 422                         err = -EPERM;
 423                         break;
 424                 }
 425
 426                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
 427                 if (err) {
 428                         err = -EFAULT;
 429                         break;
 430                 }
 431
 432                 if (desc->mode == UBI_READONLY) {
 433                         err = -EROFS;
 434                         break;
 435                 }
 436
 437                 rsvd_bytes = (long long)vol->reserved_pebs *
 438                                         ubi->leb_size-vol->data_pad;
 439                 if (bytes < 0 || bytes > rsvd_bytes) {
 440                         err = -EINVAL;
 441                         break;
 442                 }
 443
 444                 err = get_exclusive(desc);
 445                 if (err < 0)
 446                         break;
 447
 448                 err = ubi_start_update(ubi, vol, bytes);
 449                 if (bytes == 0)
 450                         revoke_exclusive(desc, UBI_READWRITE);
 451                 break;
 452         }
 453
 454         /* Atomic logical eraseblock change command */
 455         case UBI_IOCEBCH:
 456         {
 457                 struct ubi_leb_change_req req;
 458
 459                 err = copy_from_user(&req, argp,
 460                                      sizeof(struct ubi_leb_change_req));
 461                 if (err) {
 462                         err = -EFAULT;
 463                         break;
 464                 }
 465
 466                 if (desc->mode == UBI_READONLY ||
 467                     vol->vol_type == UBI_STATIC_VOLUME) {
 468                         err = -EROFS;
 469                         break;
 470                 }
 471
 472                 /* Validate the request */
 473                 err = -EINVAL;
 474                 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
 475                     req.bytes < 0 || req.lnum >= vol->usable_leb_size)
 476                         break;
 477                 if (req.dtype != UBI_LONGTERM && req.dtype != UBI_SHORTTERM &&
 478                     req.dtype != UBI_UNKNOWN)
 479                         break;
 480
 481                 err = get_exclusive(desc);
 482                 if (err < 0)
 483                         break;
 484
 485                 err = ubi_start_leb_change(ubi, vol, &req);
 486                 if (req.bytes == 0)
 487                         revoke_exclusive(desc, UBI_READWRITE);
 488                 break;
 489         }
 490
 491         /* Logical eraseblock erasure command */
 492         case UBI_IOCEBER:
 493         {
 494                 int32_t lnum;
 495
 496                 err = get_user(lnum, (__user int32_t *)argp);
 497                 if (err) {
 498                         err = -EFAULT;
 499                         break;
 500                 }
 501
 502                 if (desc->mode == UBI_READONLY ||
 503                     vol->vol_type == UBI_STATIC_VOLUME) {
 504                         err = -EROFS;
 505                         break;
 506                 }
 507
 508                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
 509                         err = -EINVAL;
 510                         break;
 511                 }
 512
 513                 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 514                 err = ubi_eba_unmap_leb(ubi, vol, lnum);
 515                 if (err)
 516                         break;
 517
 518                 err = ubi_wl_flush(ubi);
 519                 break;
 520         }
 521
 522         /* Logical eraseblock map command */
 523         case UBI_IOCEBMAP:
 524         {
 525                 struct ubi_map_req req;
 526
 527                 err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
 528                 if (err) {
 529                         err = -EFAULT;
 530                         break;
 531                 }
 532                 err = ubi_leb_map(desc, req.lnum, req.dtype);
 533                 break;
 534         }
 535
 536         /* Logical eraseblock un-map command */
 537         case UBI_IOCEBUNMAP:
 538         {
 539                 int32_t lnum;
 540
 541                 err = get_user(lnum, (__user int32_t *)argp);
 542                 if (err) {
 543                         err = -EFAULT;
 544                         break;
 545                 }
 546                 err = ubi_leb_unmap(desc, lnum);
 547                 break;
 548         }
 549
 550         /* Check if logical eraseblock is mapped command */
 551         case UBI_IOCEBISMAP:
 552         {
 553                 int32_t lnum;
 554
 555                 err = get_user(lnum, (__user int32_t *)argp);
 556                 if (err) {
 557                         err = -EFAULT;
 558                         break;
 559                 }
 560                 err = ubi_is_mapped(desc, lnum);
 561                 break;
 562         }
 563
 564         /* Set volume property command */
 565         case UBI_IOCSETPROP:
 566         {
 567                 struct ubi_set_prop_req req;
 568
 569                 err = copy_from_user(&req, argp,
 570                                 sizeof(struct ubi_set_prop_req));
 571                 if (err) {
 572                         err = -EFAULT;
 573                         break;
 574                 }
 575                 switch (req.property) {
 576                 case UBI_PROP_DIRECT_WRITE:
 577                         mutex_lock(&ubi->device_mutex);
 578                         desc->vol->direct_writes = !!req.value;
 579                         mutex_unlock(&ubi->device_mutex);
 580                         break;
 581                 default:
 582                         err = -EINVAL;
 583                         break;
 584                 }
 585                 break;
 586         }
 587
 588         default:
 589                 err = -ENOTTY;
 590                 break;
 591         }
 592         return err;
 593 }
 594
 595 /**
 596  * verify_mkvol_req - verify volume creation request.
 597  * @ubi: UBI device description object
 598  * @req: the request to check
 599  *
 600  * This function zero if the request is correct, and %-EINVAL if not.
 601  */
 602 static int verify_mkvol_req(const struct ubi_device *ubi,
 603                             const struct ubi_mkvol_req *req)
 604 {
 605         int n, err = -EINVAL;
 606
 607         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
 608             req->name_len < 0)
 609                 goto bad;
 610
 611         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
 612             req->vol_id != UBI_VOL_NUM_AUTO)
 613                 goto bad;
 614
 615         if (req->alignment == 0)
 616                 goto bad;
 617
 618         if (req->bytes == 0)
 619                 goto bad;
 620
 621         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
 622             req->vol_type != UBI_STATIC_VOLUME)
 623                 goto bad;
 624
 625         if (req->alignment > ubi->leb_size)
 626                 goto bad;
 627
 628         n = req->alignment & (ubi->min_io_size - 1);
 629         if (req->alignment != 1 && n)
 630                 goto bad;
 631
 632         if (req->name_len > UBI_VOL_NAME_MAX) {
 633                 err = -ENAMETOOLONG;
 634                 goto bad;
 635         }
 636
 637         n = strnlen(req->name, req->name_len + 1);
 638         if (n != req->name_len)
 639                 goto bad;
 640
 641         return 0;
 642
 643 bad:
 644         dbg_err("bad volume creation request");
 645         ubi_dbg_dump_mkvol_req(req);
 646         return err;
 647 }
 648
 649 /**
 650  * verify_rsvol_req - verify volume re-size request.
 651  * @ubi: UBI device description object
 652  * @req: the request to check
 653  *
 654  * This function returns zero if the request is correct, and %-EINVAL if not.
 655  */
 656 static int verify_rsvol_req(const struct ubi_device *ubi,
 657                             const struct ubi_rsvol_req *req)
 658 {
 659         if (req->bytes <= 0)
 660                 return -EINVAL;
 661
 662         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
 663                 return -EINVAL;
 664
 665         return 0;
 666 }
 667
 668 /**
 669  * rename_volumes - rename UBI volumes.
 670  * @ubi: UBI device description object
 671  * @req: volumes re-name request
 672  *
 673  * This is a helper function for the volume re-name IOCTL which validates the
 674  * the request, opens the volume and calls corresponding volumes management
 675  * function. Returns zero in case of success and a negative error code in case
 676  * of failure.
 677  */
 678 static int rename_volumes(struct ubi_device *ubi,
 679                           struct ubi_rnvol_req *req)
 680 {
 681         int i, n, err;
 682         struct list_head rename_list;
 683         struct ubi_rename_entry *re, *re1;
 684
 685         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
 686                 return -EINVAL;
 687
 688         if (req->count == 0)
 689                 return 0;
 690
 691         /* Validate volume IDs and names in the request */
 692         for (i = 0; i < req->count; i++) {
 693                 if (req->ents[i].vol_id < 0 ||
 694                     req->ents[i].vol_id >= ubi->vtbl_slots)
 695                         return -EINVAL;
 696                 if (req->ents[i].name_len < 0)
 697                         return -EINVAL;
 698                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
 699                         return -ENAMETOOLONG;
 700                 req->ents[i].name[req->ents[i].name_len] = '\0';
 701                 n = strlen(req->ents[i].name);
 702                 if (n != req->ents[i].name_len)
 703                         err = -EINVAL;
 704         }
 705
 706         /* Make sure volume IDs and names are unique */
 707         for (i = 0; i < req->count - 1; i++) {
 708                 for (n = i + 1; n < req->count; n++) {
 709                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
 710                                 dbg_err("duplicated volume id %d",
 711                                         req->ents[i].vol_id);
 712                                 return -EINVAL;
 713                         }
 714                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
 715                                 dbg_err("duplicated volume name \"%s\"",
 716                                         req->ents[i].name);
 717                                 return -EINVAL;
 718                         }
 719                 }
 720         }
 721
 722         /* Create the re-name list */
 723         INIT_LIST_HEAD(&rename_list);
 724         for (i = 0; i < req->count; i++) {
 725                 int vol_id = req->ents[i].vol_id;
 726                 int name_len = req->ents[i].name_len;
 727                 const char *name = req->ents[i].name;
 728
 729                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 730                 if (!re) {
 731                         err = -ENOMEM;
 732                         goto out_free;
 733                 }
 734
 735                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 736                 if (IS_ERR(re->desc)) {
 737                         err = PTR_ERR(re->desc);
 738                         dbg_err("cannot open volume %d, error %d", vol_id, err);
 739                         kfree(re);
 740                         goto out_free;
 741                 }
 742
 743                 /* Skip this re-naming if the name does not really change */
 744                 if (re->desc->vol->name_len == name_len &&
 745                     !memcmp(re->desc->vol->name, name, name_len)) {
 746                         ubi_close_volume(re->desc);
 747                         kfree(re);
 748                         continue;
 749                 }
 750
 751                 re->new_name_len = name_len;
 752                 memcpy(re->new_name, name, name_len);
 753                 list_add_tail(&re->list, &rename_list);
 754                 dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
 755                         vol_id, re->desc->vol->name, name);
 756         }
 757
 758         if (list_empty(&rename_list))
 759                 return 0;
 760
 761         /* Find out the volumes which have to be removed */
 762         list_for_each_entry(re, &rename_list, list) {
 763                 struct ubi_volume_desc *desc;
 764                 int no_remove_needed = 0;
 765
 766                 /*
 767                  * Volume @re->vol_id is going to be re-named to
 768                  * @re->new_name, while its current name is @name. If a volume
 769                  * with name @re->new_name currently exists, it has to be
 770                  * removed, unless it is also re-named in the request (@req).
 771                  */
 772                 list_for_each_entry(re1, &rename_list, list) {
 773                         if (re->new_name_len == re1->desc->vol->name_len &&
 774                             !memcmp(re->new_name, re1->desc->vol->name,
 775                                     re1->desc->vol->name_len)) {
 776                                 no_remove_needed = 1;
 777                                 break;
 778                         }
 779                 }
 780
 781                 if (no_remove_needed)
 782                         continue;
 783
 784                 /*
 785                  * It seems we need to remove volume with name @re->new_name,
 786                  * if it exists.
 787                  */
 788                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
 789                                           UBI_EXCLUSIVE);
 790                 if (IS_ERR(desc)) {
 791                         err = PTR_ERR(desc);
 792                         if (err == -ENODEV)
 793                                 /* Re-naming into a non-existing volume name */
 794                                 continue;
 795
 796                         /* The volume exists but busy, or an error occurred */
 797                         dbg_err("cannot open volume \"%s\", error %d",
 798                                 re->new_name, err);
 799                         goto out_free;
 800                 }
 801
 802                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 803                 if (!re) {
 804                         err = -ENOMEM;
 805                         ubi_close_volume(desc);
 806                         goto out_free;
 807                 }
 808
 809                 re->remove = 1;
 810                 re->desc = desc;
 811                 list_add(&re->list, &rename_list);
 812                 dbg_msg("will remove volume %d, name \"%s\"",
 813                         re->desc->vol->vol_id, re->desc->vol->name);
 814         }
 815
 816         mutex_lock(&ubi->device_mutex);
 817         err = ubi_rename_volumes(ubi, &rename_list);
 818         mutex_unlock(&ubi->device_mutex);
 819
 820 out_free:
 821         list_for_each_entry_safe(re, re1, &rename_list, list) {
 822                 ubi_close_volume(re->desc);
 823                 list_del(&re->list);
 824                 kfree(re);
 825         }
 826         return err;
 827 }
 828
 829 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 830                            unsigned long arg)
 831 {
 832         int err = 0;
 833         struct ubi_device *ubi;
 834         struct ubi_volume_desc *desc;
 835         void __user *argp = (void __user *)arg;
 836
 837         if (!capable(CAP_SYS_RESOURCE))
 838                 return -EPERM;
 839
 840         ubi = ubi_get_by_major(imajor(file->f_mapping->host));
 841         if (!ubi)
 842                 return -ENODEV;
 843
 844         switch (cmd) {
 845         /* Create volume command */
 846         case UBI_IOCMKVOL:
 847         {
 848                 struct ubi_mkvol_req req;
 849
 850                 dbg_gen("create volume");
 851                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
 852                 if (err) {
 853                         err = -EFAULT;
 854                         break;
 855                 }
 856
 857                 err = verify_mkvol_req(ubi, &req);
 858                 if (err)
 859                         break;
 860
 861                 mutex_lock(&ubi->device_mutex);
 862                 err = ubi_create_volume(ubi, &req);
 863                 mutex_unlock(&ubi->device_mutex);
 864                 if (err)
 865                         break;
 866
 867                 err = put_user(req.vol_id, (__user int32_t *)argp);
 868                 if (err)
 869                         err = -EFAULT;
 870
 871                 break;
 872         }
 873
 874         /* Remove volume command */
 875         case UBI_IOCRMVOL:
 876         {
 877                 int vol_id;
 878
 879                 dbg_gen("remove volume");
 880                 err = get_user(vol_id, (__user int32_t *)argp);
 881                 if (err) {
 882                         err = -EFAULT;
 883                         break;
 884                 }
 885
 886                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 887                 if (IS_ERR(desc)) {
 888                         err = PTR_ERR(desc);
 889                         break;
 890                 }
 891
 892                 mutex_lock(&ubi->device_mutex);
 893                 err = ubi_remove_volume(desc, 0);
 894                 mutex_unlock(&ubi->device_mutex);
 895
 896                 /*
 897                  * The volume is deleted (unless an error occurred), and the
 898                  * 'struct ubi_volume' object will be freed when
 899                  * 'ubi_close_volume()' will call 'put_device()'.
 900                  */
 901                 ubi_close_volume(desc);
 902                 break;
 903         }
 904
 905         /* Re-size volume command */
 906         case UBI_IOCRSVOL:
 907         {
 908                 int pebs;
 909                 struct ubi_rsvol_req req;
 910
 911                 dbg_gen("re-size volume");
 912                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
 913                 if (err) {
 914                         err = -EFAULT;
 915                         break;
 916                 }
 917
 918                 err = verify_rsvol_req(ubi, &req);
 919                 if (err)
 920                         break;
 921
 922                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
 923                 if (IS_ERR(desc)) {
 924                         err = PTR_ERR(desc);
 925                         break;
 926                 }
 927
 928                 pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
 929                                desc->vol->usable_leb_size);
 930
 931                 mutex_lock(&ubi->device_mutex);
 932                 err = ubi_resize_volume(desc, pebs);
 933                 mutex_unlock(&ubi->device_mutex);
 934                 ubi_close_volume(desc);
 935                 break;
 936         }
 937
 938         /* Re-name volumes command */
 939         case UBI_IOCRNVOL:
 940         {
 941                 struct ubi_rnvol_req *req;
 942
 943                 dbg_msg("re-name volumes");
 944                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
 945                 if (!req) {
 946                         err = -ENOMEM;
 947                         break;
 948                 };
 949
 950                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
 951                 if (err) {
 952                         err = -EFAULT;
 953                         kfree(req);
 954                         break;
 955                 }
 956
 957                 err = rename_volumes(ubi, req);
 958                 kfree(req);
 959                 break;
 960         }
 961
 962         default:
 963                 err = -ENOTTY;
 964                 break;
 965         }
 966
 967         ubi_put_device(ubi);
 968         return err;
 969 }
 970
 971 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
 972                             unsigned long arg)
 973 {
 974         int err = 0;
 975         void __user *argp = (void __user *)arg;
 976
 977         if (!capable(CAP_SYS_RESOURCE))
 978                 return -EPERM;
 979
 980         switch (cmd) {
 981         /* Attach an MTD device command */
 982         case UBI_IOCATT:
 983         {
 984                 struct ubi_attach_req req;
 985                 struct mtd_info *mtd;
 986
 987                 dbg_gen("attach MTD device");
 988                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
 989                 if (err) {
 990                         err = -EFAULT;
 991                         break;
 992                 }
 993
 994                 if (req.mtd_num < 0 ||
 995                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
 996                         err = -EINVAL;
 997                         break;
 998                 }
 999
1000                 mtd = get_mtd_device(NULL, req.mtd_num);
1001                 if (IS_ERR(mtd)) {
1002                         err = PTR_ERR(mtd);
1003                         break;
1004                 }
1005
1006                 /*
1007                  * Note, further request verification is done by
1008                  * 'ubi_attach_mtd_dev()'.
1009                  */
1010                 mutex_lock(&ubi_devices_mutex);
1011                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
1012                 mutex_unlock(&ubi_devices_mutex);
1013                 if (err < 0)
1014                         put_mtd_device(mtd);
1015                 else
1016                         /* @err contains UBI device number */
1017                         err = put_user(err, (__user int32_t *)argp);
1018
1019                 break;
1020         }
1021
1022         /* Detach an MTD device command */
1023         case UBI_IOCDET:
1024         {
1025                 int ubi_num;
1026
1027                 dbg_gen("dettach MTD device");
1028                 err = get_user(ubi_num, (__user int32_t *)argp);
1029                 if (err) {
1030                         err = -EFAULT;
1031                         break;
1032                 }
1033
1034                 mutex_lock(&ubi_devices_mutex);
1035                 err = ubi_detach_mtd_dev(ubi_num, 0);
1036                 mutex_unlock(&ubi_devices_mutex);
1037                 break;
1038         }
1039
1040         default:
1041                 err = -ENOTTY;
1042                 break;
1043         }
1044
1045         return err;
1046 }
1047
1048 #ifdef CONFIG_COMPAT
1049 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1050                                   unsigned long arg)
1051 {
1052         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1053
1054         return vol_cdev_ioctl(file, cmd, translated_arg);
1055 }
1056
1057 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1058                                   unsigned long arg)
1059 {
1060         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1061
1062         return ubi_cdev_ioctl(file, cmd, translated_arg);
1063 }
1064
1065 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1066                                    unsigned long arg)
1067 {
1068         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1069
1070         return ctrl_cdev_ioctl(file, cmd, translated_arg);
1071 }
1072 #else
1073 #define vol_cdev_compat_ioctl  NULL
1074 #define ubi_cdev_compat_ioctl  NULL
1075 #define ctrl_cdev_compat_ioctl NULL
1076 #endif
1077
1078 /* UBI volume character device operations */
1079 const struct file_operations ubi_vol_cdev_operations = {
1080         .owner          = THIS_MODULE,
1081         .open           = vol_cdev_open,
1082         .release        = vol_cdev_release,
1083         .llseek         = vol_cdev_llseek,
1084         .read           = vol_cdev_read,
1085         .write          = vol_cdev_write,
1086         .fsync          = vol_cdev_fsync,
1087         .unlocked_ioctl = vol_cdev_ioctl,
1088         .compat_ioctl   = vol_cdev_compat_ioctl,
1089 };
1090
1091 /* UBI character device operations */
1092 const struct file_operations ubi_cdev_operations = {
1093         .owner          = THIS_MODULE,
1094         .llseek         = no_llseek,
1095         .unlocked_ioctl = ubi_cdev_ioctl,
1096         .compat_ioctl   = ubi_cdev_compat_ioctl,
1097 };
1098
1099 /* UBI control character device operations */
1100 const struct file_operations ubi_ctrl_cdev_operations = {
1101         .owner          = THIS_MODULE,
1102         .unlocked_ioctl = ctrl_cdev_ioctl,
1103         .compat_ioctl   = ctrl_cdev_compat_ioctl,
1104 };