drivers/mtd/ubi/cdev.c

   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                 ubi_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 for volume %d:%d, cancel",
 144                         vol->upd_received, vol->upd_bytes, vol->ubi->ubi_num,
 145                         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
 159         if (vol->updating) {
 160                 /* Update is in progress, seeking is prohibited */
 161                 ubi_err("updating");
 162                 return -EBUSY;
 163         }
 164
 165         return fixed_size_llseek(file, offset, origin, vol->used_bytes);
 166 }
 167
 168 static int vol_cdev_fsync(struct file *file, loff_t start, loff_t end,
 169                           int datasync)
 170 {
 171         struct ubi_volume_desc *desc = file->private_data;
 172         struct ubi_device *ubi = desc->vol->ubi;
 173         struct inode *inode = file_inode(file);
 174         int err;
 175         mutex_lock(&inode->i_mutex);
 176         err = ubi_sync(ubi->ubi_num);
 177         mutex_unlock(&inode->i_mutex);
 178         return err;
 179 }
 180
 181
 182 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 183                              loff_t *offp)
 184 {
 185         struct ubi_volume_desc *desc = file->private_data;
 186         struct ubi_volume *vol = desc->vol;
 187         struct ubi_device *ubi = vol->ubi;
 188         int err, lnum, off, len,  tbuf_size;
 189         size_t count_save = count;
 190         void *tbuf;
 191
 192         dbg_gen("read %zd bytes from offset %lld of volume %d",
 193                 count, *offp, vol->vol_id);
 194
 195         if (vol->updating) {
 196                 ubi_err("updating");
 197                 return -EBUSY;
 198         }
 199         if (vol->upd_marker) {
 200                 ubi_err("damaged volume, update marker is set");
 201                 return -EBADF;
 202         }
 203         if (*offp == vol->used_bytes || count == 0)
 204                 return 0;
 205
 206         if (vol->corrupted)
 207                 dbg_gen("read from corrupted volume %d", vol->vol_id);
 208
 209         if (*offp + count > vol->used_bytes)
 210                 count_save = count = vol->used_bytes - *offp;
 211
 212         tbuf_size = vol->usable_leb_size;
 213         if (count < tbuf_size)
 214                 tbuf_size = ALIGN(count, ubi->min_io_size);
 215         tbuf = vmalloc(tbuf_size);
 216         if (!tbuf)
 217                 return -ENOMEM;
 218
 219         len = count > tbuf_size ? tbuf_size : count;
 220         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 221
 222         do {
 223                 cond_resched();
 224
 225                 if (off + len >= vol->usable_leb_size)
 226                         len = vol->usable_leb_size - off;
 227
 228                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
 229                 if (err)
 230                         break;
 231
 232                 off += len;
 233                 if (off == vol->usable_leb_size) {
 234                         lnum += 1;
 235                         off -= vol->usable_leb_size;
 236                 }
 237
 238                 count -= len;
 239                 *offp += len;
 240
 241                 err = copy_to_user(buf, tbuf, len);
 242                 if (err) {
 243                         err = -EFAULT;
 244                         break;
 245                 }
 246
 247                 buf += len;
 248                 len = count > tbuf_size ? tbuf_size : count;
 249         } while (count);
 250
 251         vfree(tbuf);
 252         return err ? err : count_save - count;
 253 }
 254
 255 /*
 256  * This function allows to directly write to dynamic UBI volumes, without
 257  * issuing the volume update operation.
 258  */
 259 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 260                                      size_t count, loff_t *offp)
 261 {
 262         struct ubi_volume_desc *desc = file->private_data;
 263         struct ubi_volume *vol = desc->vol;
 264         struct ubi_device *ubi = vol->ubi;
 265         int lnum, off, len, tbuf_size, err = 0;
 266         size_t count_save = count;
 267         char *tbuf;
 268
 269         if (!vol->direct_writes)
 270                 return -EPERM;
 271
 272         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
 273                 count, *offp, vol->vol_id);
 274
 275         if (vol->vol_type == UBI_STATIC_VOLUME)
 276                 return -EROFS;
 277
 278         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 279         if (off & (ubi->min_io_size - 1)) {
 280                 ubi_err("unaligned position");
 281                 return -EINVAL;
 282         }
 283
 284         if (*offp + count > vol->used_bytes)
 285                 count_save = count = vol->used_bytes - *offp;
 286
 287         /* We can write only in fractions of the minimum I/O unit */
 288         if (count & (ubi->min_io_size - 1)) {
 289                 ubi_err("unaligned write length");
 290                 return -EINVAL;
 291         }
 292
 293         tbuf_size = vol->usable_leb_size;
 294         if (count < tbuf_size)
 295                 tbuf_size = ALIGN(count, ubi->min_io_size);
 296         tbuf = vmalloc(tbuf_size);
 297         if (!tbuf)
 298                 return -ENOMEM;
 299
 300         len = count > tbuf_size ? tbuf_size : count;
 301
 302         while (count) {
 303                 cond_resched();
 304
 305                 if (off + len >= vol->usable_leb_size)
 306                         len = vol->usable_leb_size - off;
 307
 308                 err = copy_from_user(tbuf, buf, len);
 309                 if (err) {
 310                         err = -EFAULT;
 311                         break;
 312                 }
 313
 314                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len);
 315                 if (err)
 316                         break;
 317
 318                 off += len;
 319                 if (off == vol->usable_leb_size) {
 320                         lnum += 1;
 321                         off -= vol->usable_leb_size;
 322                 }
 323
 324                 count -= len;
 325                 *offp += len;
 326                 buf += len;
 327                 len = count > tbuf_size ? tbuf_size : count;
 328         }
 329
 330         vfree(tbuf);
 331         return err ? err : count_save - count;
 332 }
 333
 334 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 335                               size_t count, loff_t *offp)
 336 {
 337         int err = 0;
 338         struct ubi_volume_desc *desc = file->private_data;
 339         struct ubi_volume *vol = desc->vol;
 340         struct ubi_device *ubi = vol->ubi;
 341
 342         if (!vol->updating && !vol->changing_leb)
 343                 return vol_cdev_direct_write(file, buf, count, offp);
 344
 345         if (vol->updating)
 346                 err = ubi_more_update_data(ubi, vol, buf, count);
 347         else
 348                 err = ubi_more_leb_change_data(ubi, vol, buf, count);
 349
 350         if (err < 0) {
 351                 ubi_err("cannot accept more %zd bytes of data, error %d",
 352                         count, err);
 353                 return err;
 354         }
 355
 356         if (err) {
 357                 /*
 358                  * The operation is finished, @err contains number of actually
 359                  * written bytes.
 360                  */
 361                 count = err;
 362
 363                 if (vol->changing_leb) {
 364                         revoke_exclusive(desc, UBI_READWRITE);
 365                         return count;
 366                 }
 367
 368                 err = ubi_check_volume(ubi, vol->vol_id);
 369                 if (err < 0)
 370                         return err;
 371
 372                 if (err) {
 373                         ubi_warn("volume %d on UBI device %d is corrupted",
 374                                  vol->vol_id, ubi->ubi_num);
 375                         vol->corrupted = 1;
 376                 }
 377                 vol->checked = 1;
 378                 ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
 379                 revoke_exclusive(desc, UBI_READWRITE);
 380         }
 381
 382         return count;
 383 }
 384
 385 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
 386                            unsigned long arg)
 387 {
 388         int err = 0;
 389         struct ubi_volume_desc *desc = file->private_data;
 390         struct ubi_volume *vol = desc->vol;
 391         struct ubi_device *ubi = vol->ubi;
 392         void __user *argp = (void __user *)arg;
 393
 394         switch (cmd) {
 395         /* Volume update command */
 396         case UBI_IOCVOLUP:
 397         {
 398                 int64_t bytes, rsvd_bytes;
 399
 400                 if (!capable(CAP_SYS_RESOURCE)) {
 401                         err = -EPERM;
 402                         break;
 403                 }
 404
 405                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
 406                 if (err) {
 407                         err = -EFAULT;
 408                         break;
 409                 }
 410
 411                 if (desc->mode == UBI_READONLY) {
 412                         err = -EROFS;
 413                         break;
 414                 }
 415
 416                 rsvd_bytes = (long long)vol->reserved_pebs *
 417                                         ubi->leb_size-vol->data_pad;
 418                 if (bytes < 0 || bytes > rsvd_bytes) {
 419                         err = -EINVAL;
 420                         break;
 421                 }
 422
 423                 err = get_exclusive(desc);
 424                 if (err < 0)
 425                         break;
 426
 427                 err = ubi_start_update(ubi, vol, bytes);
 428                 if (bytes == 0)
 429                         revoke_exclusive(desc, UBI_READWRITE);
 430                 break;
 431         }
 432
 433         /* Atomic logical eraseblock change command */
 434         case UBI_IOCEBCH:
 435         {
 436                 struct ubi_leb_change_req req;
 437
 438                 err = copy_from_user(&req, argp,
 439                                      sizeof(struct ubi_leb_change_req));
 440                 if (err) {
 441                         err = -EFAULT;
 442                         break;
 443                 }
 444
 445                 if (desc->mode == UBI_READONLY ||
 446                     vol->vol_type == UBI_STATIC_VOLUME) {
 447                         err = -EROFS;
 448                         break;
 449                 }
 450
 451                 /* Validate the request */
 452                 err = -EINVAL;
 453                 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
 454                     req.bytes < 0 || req.lnum >= vol->usable_leb_size)
 455                         break;
 456
 457                 err = get_exclusive(desc);
 458                 if (err < 0)
 459                         break;
 460
 461                 err = ubi_start_leb_change(ubi, vol, &req);
 462                 if (req.bytes == 0)
 463                         revoke_exclusive(desc, UBI_READWRITE);
 464                 break;
 465         }
 466
 467         /* Logical eraseblock erasure command */
 468         case UBI_IOCEBER:
 469         {
 470                 int32_t lnum;
 471
 472                 err = get_user(lnum, (__user int32_t *)argp);
 473                 if (err) {
 474                         err = -EFAULT;
 475                         break;
 476                 }
 477
 478                 if (desc->mode == UBI_READONLY ||
 479                     vol->vol_type == UBI_STATIC_VOLUME) {
 480                         err = -EROFS;
 481                         break;
 482                 }
 483
 484                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
 485                         err = -EINVAL;
 486                         break;
 487                 }
 488
 489                 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 490                 err = ubi_eba_unmap_leb(ubi, vol, lnum);
 491                 if (err)
 492                         break;
 493
 494                 err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
 495                 break;
 496         }
 497
 498         /* Logical eraseblock map command */
 499         case UBI_IOCEBMAP:
 500         {
 501                 struct ubi_map_req req;
 502
 503                 err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
 504                 if (err) {
 505                         err = -EFAULT;
 506                         break;
 507                 }
 508                 err = ubi_leb_map(desc, req.lnum);
 509                 break;
 510         }
 511
 512         /* Logical eraseblock un-map command */
 513         case UBI_IOCEBUNMAP:
 514         {
 515                 int32_t lnum;
 516
 517                 err = get_user(lnum, (__user int32_t *)argp);
 518                 if (err) {
 519                         err = -EFAULT;
 520                         break;
 521                 }
 522                 err = ubi_leb_unmap(desc, lnum);
 523                 break;
 524         }
 525
 526         /* Check if logical eraseblock is mapped command */
 527         case UBI_IOCEBISMAP:
 528         {
 529                 int32_t lnum;
 530
 531                 err = get_user(lnum, (__user int32_t *)argp);
 532                 if (err) {
 533                         err = -EFAULT;
 534                         break;
 535                 }
 536                 err = ubi_is_mapped(desc, lnum);
 537                 break;
 538         }
 539
 540         /* Set volume property command */
 541         case UBI_IOCSETVOLPROP:
 542         {
 543                 struct ubi_set_vol_prop_req req;
 544
 545                 err = copy_from_user(&req, argp,
 546                                      sizeof(struct ubi_set_vol_prop_req));
 547                 if (err) {
 548                         err = -EFAULT;
 549                         break;
 550                 }
 551                 switch (req.property) {
 552                 case UBI_VOL_PROP_DIRECT_WRITE:
 553                         mutex_lock(&ubi->device_mutex);
 554                         desc->vol->direct_writes = !!req.value;
 555                         mutex_unlock(&ubi->device_mutex);
 556                         break;
 557                 default:
 558                         err = -EINVAL;
 559                         break;
 560                 }
 561                 break;
 562         }
 563
 564         default:
 565                 err = -ENOTTY;
 566                 break;
 567         }
 568         return err;
 569 }
 570
 571 /**
 572  * verify_mkvol_req - verify volume creation request.
 573  * @ubi: UBI device description object
 574  * @req: the request to check
 575  *
 576  * This function zero if the request is correct, and %-EINVAL if not.
 577  */
 578 static int verify_mkvol_req(const struct ubi_device *ubi,
 579                             const struct ubi_mkvol_req *req)
 580 {
 581         int n, err = -EINVAL;
 582
 583         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
 584             req->name_len < 0)
 585                 goto bad;
 586
 587         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
 588             req->vol_id != UBI_VOL_NUM_AUTO)
 589                 goto bad;
 590
 591         if (req->alignment == 0)
 592                 goto bad;
 593
 594         if (req->bytes == 0)
 595                 goto bad;
 596
 597         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
 598             req->vol_type != UBI_STATIC_VOLUME)
 599                 goto bad;
 600
 601         if (req->alignment > ubi->leb_size)
 602                 goto bad;
 603
 604         n = req->alignment & (ubi->min_io_size - 1);
 605         if (req->alignment != 1 && n)
 606                 goto bad;
 607
 608         if (!req->name[0] || !req->name_len)
 609                 goto bad;
 610
 611         if (req->name_len > UBI_VOL_NAME_MAX) {
 612                 err = -ENAMETOOLONG;
 613                 goto bad;
 614         }
 615
 616         n = strnlen(req->name, req->name_len + 1);
 617         if (n != req->name_len)
 618                 goto bad;
 619
 620         return 0;
 621
 622 bad:
 623         ubi_err("bad volume creation request");
 624         ubi_dump_mkvol_req(req);
 625         return err;
 626 }
 627
 628 /**
 629  * verify_rsvol_req - verify volume re-size request.
 630  * @ubi: UBI device description object
 631  * @req: the request to check
 632  *
 633  * This function returns zero if the request is correct, and %-EINVAL if not.
 634  */
 635 static int verify_rsvol_req(const struct ubi_device *ubi,
 636                             const struct ubi_rsvol_req *req)
 637 {
 638         if (req->bytes <= 0)
 639                 return -EINVAL;
 640
 641         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
 642                 return -EINVAL;
 643
 644         return 0;
 645 }
 646
 647 /**
 648  * rename_volumes - rename UBI volumes.
 649  * @ubi: UBI device description object
 650  * @req: volumes re-name request
 651  *
 652  * This is a helper function for the volume re-name IOCTL which validates the
 653  * the request, opens the volume and calls corresponding volumes management
 654  * function. Returns zero in case of success and a negative error code in case
 655  * of failure.
 656  */
 657 static int rename_volumes(struct ubi_device *ubi,
 658                           struct ubi_rnvol_req *req)
 659 {
 660         int i, n, err;
 661         struct list_head rename_list;
 662         struct ubi_rename_entry *re, *re1;
 663
 664         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
 665                 return -EINVAL;
 666
 667         if (req->count == 0)
 668                 return 0;
 669
 670         /* Validate volume IDs and names in the request */
 671         for (i = 0; i < req->count; i++) {
 672                 if (req->ents[i].vol_id < 0 ||
 673                     req->ents[i].vol_id >= ubi->vtbl_slots)
 674                         return -EINVAL;
 675                 if (req->ents[i].name_len < 0)
 676                         return -EINVAL;
 677                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
 678                         return -ENAMETOOLONG;
 679                 req->ents[i].name[req->ents[i].name_len] = '\0';
 680                 n = strlen(req->ents[i].name);
 681                 if (n != req->ents[i].name_len)
 682                         err = -EINVAL;
 683         }
 684
 685         /* Make sure volume IDs and names are unique */
 686         for (i = 0; i < req->count - 1; i++) {
 687                 for (n = i + 1; n < req->count; n++) {
 688                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
 689                                 ubi_err("duplicated volume id %d",
 690                                         req->ents[i].vol_id);
 691                                 return -EINVAL;
 692                         }
 693                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
 694                                 ubi_err("duplicated volume name \"%s\"",
 695                                         req->ents[i].name);
 696                                 return -EINVAL;
 697                         }
 698                 }
 699         }
 700
 701         /* Create the re-name list */
 702         INIT_LIST_HEAD(&rename_list);
 703         for (i = 0; i < req->count; i++) {
 704                 int vol_id = req->ents[i].vol_id;
 705                 int name_len = req->ents[i].name_len;
 706                 const char *name = req->ents[i].name;
 707
 708                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 709                 if (!re) {
 710                         err = -ENOMEM;
 711                         goto out_free;
 712                 }
 713
 714                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 715                 if (IS_ERR(re->desc)) {
 716                         err = PTR_ERR(re->desc);
 717                         ubi_err("cannot open volume %d, error %d", vol_id, err);
 718                         kfree(re);
 719                         goto out_free;
 720                 }
 721
 722                 /* Skip this re-naming if the name does not really change */
 723                 if (re->desc->vol->name_len == name_len &&
 724                     !memcmp(re->desc->vol->name, name, name_len)) {
 725                         ubi_close_volume(re->desc);
 726                         kfree(re);
 727                         continue;
 728                 }
 729
 730                 re->new_name_len = name_len;
 731                 memcpy(re->new_name, name, name_len);
 732                 list_add_tail(&re->list, &rename_list);
 733                 dbg_gen("will rename volume %d from \"%s\" to \"%s\"",
 734                         vol_id, re->desc->vol->name, name);
 735         }
 736
 737         if (list_empty(&rename_list))
 738                 return 0;
 739
 740         /* Find out the volumes which have to be removed */
 741         list_for_each_entry(re, &rename_list, list) {
 742                 struct ubi_volume_desc *desc;
 743                 int no_remove_needed = 0;
 744
 745                 /*
 746                  * Volume @re->vol_id is going to be re-named to
 747                  * @re->new_name, while its current name is @name. If a volume
 748                  * with name @re->new_name currently exists, it has to be
 749                  * removed, unless it is also re-named in the request (@req).
 750                  */
 751                 list_for_each_entry(re1, &rename_list, list) {
 752                         if (re->new_name_len == re1->desc->vol->name_len &&
 753                             !memcmp(re->new_name, re1->desc->vol->name,
 754                                     re1->desc->vol->name_len)) {
 755                                 no_remove_needed = 1;
 756                                 break;
 757                         }
 758                 }
 759
 760                 if (no_remove_needed)
 761                         continue;
 762
 763                 /*
 764                  * It seems we need to remove volume with name @re->new_name,
 765                  * if it exists.
 766                  */
 767                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
 768                                           UBI_EXCLUSIVE);
 769                 if (IS_ERR(desc)) {
 770                         err = PTR_ERR(desc);
 771                         if (err == -ENODEV)
 772                                 /* Re-naming into a non-existing volume name */
 773                                 continue;
 774
 775                         /* The volume exists but busy, or an error occurred */
 776                         ubi_err("cannot open volume \"%s\", error %d",
 777                                 re->new_name, err);
 778                         goto out_free;
 779                 }
 780
 781                 re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 782                 if (!re1) {
 783                         err = -ENOMEM;
 784                         ubi_close_volume(desc);
 785                         goto out_free;
 786                 }
 787
 788                 re1->remove = 1;
 789                 re1->desc = desc;
 790                 list_add(&re1->list, &rename_list);
 791                 dbg_gen("will remove volume %d, name \"%s\"",
 792                         re1->desc->vol->vol_id, re1->desc->vol->name);
 793         }
 794
 795         mutex_lock(&ubi->device_mutex);
 796         err = ubi_rename_volumes(ubi, &rename_list);
 797         mutex_unlock(&ubi->device_mutex);
 798
 799 out_free:
 800         list_for_each_entry_safe(re, re1, &rename_list, list) {
 801                 ubi_close_volume(re->desc);
 802                 list_del(&re->list);
 803                 kfree(re);
 804         }
 805         return err;
 806 }
 807
 808 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 809                            unsigned long arg)
 810 {
 811         int err = 0;
 812         struct ubi_device *ubi;
 813         struct ubi_volume_desc *desc;
 814         void __user *argp = (void __user *)arg;
 815
 816         if (!capable(CAP_SYS_RESOURCE))
 817                 return -EPERM;
 818
 819         ubi = ubi_get_by_major(imajor(file->f_mapping->host));
 820         if (!ubi)
 821                 return -ENODEV;
 822
 823         switch (cmd) {
 824         /* Create volume command */
 825         case UBI_IOCMKVOL:
 826         {
 827                 struct ubi_mkvol_req req;
 828
 829                 dbg_gen("create volume");
 830                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
 831                 if (err) {
 832                         err = -EFAULT;
 833                         break;
 834                 }
 835
 836                 err = verify_mkvol_req(ubi, &req);
 837                 if (err)
 838                         break;
 839
 840                 mutex_lock(&ubi->device_mutex);
 841                 err = ubi_create_volume(ubi, &req);
 842                 mutex_unlock(&ubi->device_mutex);
 843                 if (err)
 844                         break;
 845
 846                 err = put_user(req.vol_id, (__user int32_t *)argp);
 847                 if (err)
 848                         err = -EFAULT;
 849
 850                 break;
 851         }
 852
 853         /* Remove volume command */
 854         case UBI_IOCRMVOL:
 855         {
 856                 int vol_id;
 857
 858                 dbg_gen("remove volume");
 859                 err = get_user(vol_id, (__user int32_t *)argp);
 860                 if (err) {
 861                         err = -EFAULT;
 862                         break;
 863                 }
 864
 865                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 866                 if (IS_ERR(desc)) {
 867                         err = PTR_ERR(desc);
 868                         break;
 869                 }
 870
 871                 mutex_lock(&ubi->device_mutex);
 872                 err = ubi_remove_volume(desc, 0);
 873                 mutex_unlock(&ubi->device_mutex);
 874
 875                 /*
 876                  * The volume is deleted (unless an error occurred), and the
 877                  * 'struct ubi_volume' object will be freed when
 878                  * 'ubi_close_volume()' will call 'put_device()'.
 879                  */
 880                 ubi_close_volume(desc);
 881                 break;
 882         }
 883
 884         /* Re-size volume command */
 885         case UBI_IOCRSVOL:
 886         {
 887                 int pebs;
 888                 struct ubi_rsvol_req req;
 889
 890                 dbg_gen("re-size volume");
 891                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
 892                 if (err) {
 893                         err = -EFAULT;
 894                         break;
 895                 }
 896
 897                 err = verify_rsvol_req(ubi, &req);
 898                 if (err)
 899                         break;
 900
 901                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
 902                 if (IS_ERR(desc)) {
 903                         err = PTR_ERR(desc);
 904                         break;
 905                 }
 906
 907                 pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
 908                                desc->vol->usable_leb_size);
 909
 910                 mutex_lock(&ubi->device_mutex);
 911                 err = ubi_resize_volume(desc, pebs);
 912                 mutex_unlock(&ubi->device_mutex);
 913                 ubi_close_volume(desc);
 914                 break;
 915         }
 916
 917         /* Re-name volumes command */
 918         case UBI_IOCRNVOL:
 919         {
 920                 struct ubi_rnvol_req *req;
 921
 922                 dbg_gen("re-name volumes");
 923                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
 924                 if (!req) {
 925                         err = -ENOMEM;
 926                         break;
 927                 };
 928
 929                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
 930                 if (err) {
 931                         err = -EFAULT;
 932                         kfree(req);
 933                         break;
 934                 }
 935
 936                 err = rename_volumes(ubi, req);
 937                 kfree(req);
 938                 break;
 939         }
 940
 941         default:
 942                 err = -ENOTTY;
 943                 break;
 944         }
 945
 946         ubi_put_device(ubi);
 947         return err;
 948 }
 949
 950 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
 951                             unsigned long arg)
 952 {
 953         int err = 0;
 954         void __user *argp = (void __user *)arg;
 955
 956         if (!capable(CAP_SYS_RESOURCE))
 957                 return -EPERM;
 958
 959         switch (cmd) {
 960         /* Attach an MTD device command */
 961         case UBI_IOCATT:
 962         {
 963                 struct ubi_attach_req req;
 964                 struct mtd_info *mtd;
 965
 966                 dbg_gen("attach MTD device");
 967                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
 968                 if (err) {
 969                         err = -EFAULT;
 970                         break;
 971                 }
 972
 973                 if (req.mtd_num < 0 ||
 974                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
 975                         err = -EINVAL;
 976                         break;
 977                 }
 978
 979                 mtd = get_mtd_device(NULL, req.mtd_num);
 980                 if (IS_ERR(mtd)) {
 981                         err = PTR_ERR(mtd);
 982                         break;
 983                 }
 984
 985                 /*
 986                  * Note, further request verification is done by
 987                  * 'ubi_attach_mtd_dev()'.
 988                  */
 989                 mutex_lock(&ubi_devices_mutex);
 990                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset,
 991                                          req.max_beb_per1024);
 992                 mutex_unlock(&ubi_devices_mutex);
 993                 if (err < 0)
 994                         put_mtd_device(mtd);
 995                 else
 996                         /* @err contains UBI device number */
 997                         err = put_user(err, (__user int32_t *)argp);
 998
 999                 break;
1000         }
1001
1002         /* Detach an MTD device command */
1003         case UBI_IOCDET:
1004         {
1005                 int ubi_num;
1006
1007                 dbg_gen("detach MTD device");
1008                 err = get_user(ubi_num, (__user int32_t *)argp);
1009                 if (err) {
1010                         err = -EFAULT;
1011                         break;
1012                 }
1013
1014                 mutex_lock(&ubi_devices_mutex);
1015                 err = ubi_detach_mtd_dev(ubi_num, 0);
1016                 mutex_unlock(&ubi_devices_mutex);
1017                 break;
1018         }
1019
1020         default:
1021                 err = -ENOTTY;
1022                 break;
1023         }
1024
1025         return err;
1026 }
1027
1028 #ifdef CONFIG_COMPAT
1029 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1030                                   unsigned long arg)
1031 {
1032         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1033
1034         return vol_cdev_ioctl(file, cmd, translated_arg);
1035 }
1036
1037 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1038                                   unsigned long arg)
1039 {
1040         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1041
1042         return ubi_cdev_ioctl(file, cmd, translated_arg);
1043 }
1044
1045 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1046                                    unsigned long arg)
1047 {
1048         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1049
1050         return ctrl_cdev_ioctl(file, cmd, translated_arg);
1051 }
1052 #else
1053 #define vol_cdev_compat_ioctl  NULL
1054 #define ubi_cdev_compat_ioctl  NULL
1055 #define ctrl_cdev_compat_ioctl NULL
1056 #endif
1057
1058 /* UBI volume character device operations */
1059 const struct file_operations ubi_vol_cdev_operations = {
1060         .owner          = THIS_MODULE,
1061         .open           = vol_cdev_open,
1062         .release        = vol_cdev_release,
1063         .llseek         = vol_cdev_llseek,
1064         .read           = vol_cdev_read,
1065         .write          = vol_cdev_write,
1066         .fsync          = vol_cdev_fsync,
1067         .unlocked_ioctl = vol_cdev_ioctl,
1068         .compat_ioctl   = vol_cdev_compat_ioctl,
1069 };
1070
1071 /* UBI character device operations */
1072 const struct file_operations ubi_cdev_operations = {
1073         .owner          = THIS_MODULE,
1074         .llseek         = no_llseek,
1075         .unlocked_ioctl = ubi_cdev_ioctl,
1076         .compat_ioctl   = ubi_cdev_compat_ioctl,
1077 };
1078
1079 /* UBI control character device operations */
1080 const struct file_operations ubi_ctrl_cdev_operations = {
1081         .owner          = THIS_MODULE,
1082         .unlocked_ioctl = ctrl_cdev_ioctl,
1083         .compat_ioctl   = ctrl_cdev_compat_ioctl,
1084         .llseek         = no_llseek,
1085 };