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                 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, int datasync)
 193 {
 194         struct ubi_volume_desc *desc = file->private_data;
 195         struct ubi_device *ubi = desc->vol->ubi;
 196
 197         return ubi_sync(ubi->ubi_num);
 198 }
 199
 200
 201 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 202                              loff_t *offp)
 203 {
 204         struct ubi_volume_desc *desc = file->private_data;
 205         struct ubi_volume *vol = desc->vol;
 206         struct ubi_device *ubi = vol->ubi;
 207         int err, lnum, off, len,  tbuf_size;
 208         size_t count_save = count;
 209         void *tbuf;
 210
 211         dbg_gen("read %zd bytes from offset %lld of volume %d",
 212                 count, *offp, vol->vol_id);
 213
 214         if (vol->updating) {
 215                 dbg_err("updating");
 216                 return -EBUSY;
 217         }
 218         if (vol->upd_marker) {
 219                 dbg_err("damaged volume, update marker is set");
 220                 return -EBADF;
 221         }
 222         if (*offp == vol->used_bytes || count == 0)
 223                 return 0;
 224
 225         if (vol->corrupted)
 226                 dbg_gen("read from corrupted volume %d", vol->vol_id);
 227
 228         if (*offp + count > vol->used_bytes)
 229                 count_save = count = vol->used_bytes - *offp;
 230
 231         tbuf_size = vol->usable_leb_size;
 232         if (count < tbuf_size)
 233                 tbuf_size = ALIGN(count, ubi->min_io_size);
 234         tbuf = vmalloc(tbuf_size);
 235         if (!tbuf)
 236                 return -ENOMEM;
 237
 238         len = count > tbuf_size ? tbuf_size : count;
 239         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 240
 241         do {
 242                 cond_resched();
 243
 244                 if (off + len >= vol->usable_leb_size)
 245                         len = vol->usable_leb_size - off;
 246
 247                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
 248                 if (err)
 249                         break;
 250
 251                 off += len;
 252                 if (off == vol->usable_leb_size) {
 253                         lnum += 1;
 254                         off -= vol->usable_leb_size;
 255                 }
 256
 257                 count -= len;
 258                 *offp += len;
 259
 260                 err = copy_to_user(buf, tbuf, len);
 261                 if (err) {
 262                         err = -EFAULT;
 263                         break;
 264                 }
 265
 266                 buf += len;
 267                 len = count > tbuf_size ? tbuf_size : count;
 268         } while (count);
 269
 270         vfree(tbuf);
 271         return err ? err : count_save - count;
 272 }
 273
 274 /*
 275  * This function allows to directly write to dynamic UBI volumes, without
 276  * issuing the volume update operation.
 277  */
 278 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 279                                      size_t count, loff_t *offp)
 280 {
 281         struct ubi_volume_desc *desc = file->private_data;
 282         struct ubi_volume *vol = desc->vol;
 283         struct ubi_device *ubi = vol->ubi;
 284         int lnum, off, len, tbuf_size, err = 0;
 285         size_t count_save = count;
 286         char *tbuf;
 287
 288         if (!vol->direct_writes)
 289                 return -EPERM;
 290
 291         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
 292                 count, *offp, vol->vol_id);
 293
 294         if (vol->vol_type == UBI_STATIC_VOLUME)
 295                 return -EROFS;
 296
 297         lnum = div_u64_rem(*offp, vol->usable_leb_size, &off);
 298         if (off & (ubi->min_io_size - 1)) {
 299                 dbg_err("unaligned position");
 300                 return -EINVAL;
 301         }
 302
 303         if (*offp + count > vol->used_bytes)
 304                 count_save = count = vol->used_bytes - *offp;
 305
 306         /* We can write only in fractions of the minimum I/O unit */
 307         if (count & (ubi->min_io_size - 1)) {
 308                 dbg_err("unaligned write length");
 309                 return -EINVAL;
 310         }
 311
 312         tbuf_size = vol->usable_leb_size;
 313         if (count < tbuf_size)
 314                 tbuf_size = ALIGN(count, ubi->min_io_size);
 315         tbuf = vmalloc(tbuf_size);
 316         if (!tbuf)
 317                 return -ENOMEM;
 318
 319         len = count > tbuf_size ? tbuf_size : count;
 320
 321         while (count) {
 322                 cond_resched();
 323
 324                 if (off + len >= vol->usable_leb_size)
 325                         len = vol->usable_leb_size - off;
 326
 327                 err = copy_from_user(tbuf, buf, len);
 328                 if (err) {
 329                         err = -EFAULT;
 330                         break;
 331                 }
 332
 333                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
 334                                         UBI_UNKNOWN);
 335                 if (err)
 336                         break;
 337
 338                 off += len;
 339                 if (off == vol->usable_leb_size) {
 340                         lnum += 1;
 341                         off -= vol->usable_leb_size;
 342                 }
 343
 344                 count -= len;
 345                 *offp += len;
 346                 buf += len;
 347                 len = count > tbuf_size ? tbuf_size : count;
 348         }
 349
 350         vfree(tbuf);
 351         return err ? err : count_save - count;
 352 }
 353
 354 static ssize_t vol_cdev_write(struct file *file, const char __user *buf,
 355                               size_t count, loff_t *offp)
 356 {
 357         int err = 0;
 358         struct ubi_volume_desc *desc = file->private_data;
 359         struct ubi_volume *vol = desc->vol;
 360         struct ubi_device *ubi = vol->ubi;
 361
 362         if (!vol->updating && !vol->changing_leb)
 363                 return vol_cdev_direct_write(file, buf, count, offp);
 364
 365         if (vol->updating)
 366                 err = ubi_more_update_data(ubi, vol, buf, count);
 367         else
 368                 err = ubi_more_leb_change_data(ubi, vol, buf, count);
 369
 370         if (err < 0) {
 371                 ubi_err("cannot accept more %zd bytes of data, error %d",
 372                         count, err);
 373                 return err;
 374         }
 375
 376         if (err) {
 377                 /*
 378                  * The operation is finished, @err contains number of actually
 379                  * written bytes.
 380                  */
 381                 count = err;
 382
 383                 if (vol->changing_leb) {
 384                         revoke_exclusive(desc, UBI_READWRITE);
 385                         return count;
 386                 }
 387
 388                 err = ubi_check_volume(ubi, vol->vol_id);
 389                 if (err < 0)
 390                         return err;
 391
 392                 if (err) {
 393                         ubi_warn("volume %d on UBI device %d is corrupted",
 394                                  vol->vol_id, ubi->ubi_num);
 395                         vol->corrupted = 1;
 396                 }
 397                 vol->checked = 1;
 398                 ubi_volume_notify(ubi, vol, UBI_VOLUME_UPDATED);
 399                 revoke_exclusive(desc, UBI_READWRITE);
 400         }
 401
 402         return count;
 403 }
 404
 405 static long vol_cdev_ioctl(struct file *file, unsigned int cmd,
 406                            unsigned long arg)
 407 {
 408         int err = 0;
 409         struct ubi_volume_desc *desc = file->private_data;
 410         struct ubi_volume *vol = desc->vol;
 411         struct ubi_device *ubi = vol->ubi;
 412         void __user *argp = (void __user *)arg;
 413
 414         switch (cmd) {
 415         /* Volume update command */
 416         case UBI_IOCVOLUP:
 417         {
 418                 int64_t bytes, rsvd_bytes;
 419
 420                 if (!capable(CAP_SYS_RESOURCE)) {
 421                         err = -EPERM;
 422                         break;
 423                 }
 424
 425                 err = copy_from_user(&bytes, argp, sizeof(int64_t));
 426                 if (err) {
 427                         err = -EFAULT;
 428                         break;
 429                 }
 430
 431                 if (desc->mode == UBI_READONLY) {
 432                         err = -EROFS;
 433                         break;
 434                 }
 435
 436                 rsvd_bytes = (long long)vol->reserved_pebs *
 437                                         ubi->leb_size-vol->data_pad;
 438                 if (bytes < 0 || bytes > rsvd_bytes) {
 439                         err = -EINVAL;
 440                         break;
 441                 }
 442
 443                 err = get_exclusive(desc);
 444                 if (err < 0)
 445                         break;
 446
 447                 err = ubi_start_update(ubi, vol, bytes);
 448                 if (bytes == 0)
 449                         revoke_exclusive(desc, UBI_READWRITE);
 450                 break;
 451         }
 452
 453         /* Atomic logical eraseblock change command */
 454         case UBI_IOCEBCH:
 455         {
 456                 struct ubi_leb_change_req req;
 457
 458                 err = copy_from_user(&req, argp,
 459                                      sizeof(struct ubi_leb_change_req));
 460                 if (err) {
 461                         err = -EFAULT;
 462                         break;
 463                 }
 464
 465                 if (desc->mode == UBI_READONLY ||
 466                     vol->vol_type == UBI_STATIC_VOLUME) {
 467                         err = -EROFS;
 468                         break;
 469                 }
 470
 471                 /* Validate the request */
 472                 err = -EINVAL;
 473                 if (req.lnum < 0 || req.lnum >= vol->reserved_pebs ||
 474                     req.bytes < 0 || req.lnum >= vol->usable_leb_size)
 475                         break;
 476                 if (req.dtype != UBI_LONGTERM && req.dtype != UBI_SHORTTERM &&
 477                     req.dtype != UBI_UNKNOWN)
 478                         break;
 479
 480                 err = get_exclusive(desc);
 481                 if (err < 0)
 482                         break;
 483
 484                 err = ubi_start_leb_change(ubi, vol, &req);
 485                 if (req.bytes == 0)
 486                         revoke_exclusive(desc, UBI_READWRITE);
 487                 break;
 488         }
 489
 490         /* Logical eraseblock erasure command */
 491         case UBI_IOCEBER:
 492         {
 493                 int32_t lnum;
 494
 495                 err = get_user(lnum, (__user int32_t *)argp);
 496                 if (err) {
 497                         err = -EFAULT;
 498                         break;
 499                 }
 500
 501                 if (desc->mode == UBI_READONLY ||
 502                     vol->vol_type == UBI_STATIC_VOLUME) {
 503                         err = -EROFS;
 504                         break;
 505                 }
 506
 507                 if (lnum < 0 || lnum >= vol->reserved_pebs) {
 508                         err = -EINVAL;
 509                         break;
 510                 }
 511
 512                 dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 513                 err = ubi_eba_unmap_leb(ubi, vol, lnum);
 514                 if (err)
 515                         break;
 516
 517                 err = ubi_wl_flush(ubi);
 518                 break;
 519         }
 520
 521         /* Logical eraseblock map command */
 522         case UBI_IOCEBMAP:
 523         {
 524                 struct ubi_map_req req;
 525
 526                 err = copy_from_user(&req, argp, sizeof(struct ubi_map_req));
 527                 if (err) {
 528                         err = -EFAULT;
 529                         break;
 530                 }
 531                 err = ubi_leb_map(desc, req.lnum, req.dtype);
 532                 break;
 533         }
 534
 535         /* Logical eraseblock un-map command */
 536         case UBI_IOCEBUNMAP:
 537         {
 538                 int32_t lnum;
 539
 540                 err = get_user(lnum, (__user int32_t *)argp);
 541                 if (err) {
 542                         err = -EFAULT;
 543                         break;
 544                 }
 545                 err = ubi_leb_unmap(desc, lnum);
 546                 break;
 547         }
 548
 549         /* Check if logical eraseblock is mapped command */
 550         case UBI_IOCEBISMAP:
 551         {
 552                 int32_t lnum;
 553
 554                 err = get_user(lnum, (__user int32_t *)argp);
 555                 if (err) {
 556                         err = -EFAULT;
 557                         break;
 558                 }
 559                 err = ubi_is_mapped(desc, lnum);
 560                 break;
 561         }
 562
 563         /* Set volume property command */
 564         case UBI_IOCSETPROP:
 565         {
 566                 struct ubi_set_prop_req req;
 567
 568                 err = copy_from_user(&req, argp,
 569                                 sizeof(struct ubi_set_prop_req));
 570                 if (err) {
 571                         err = -EFAULT;
 572                         break;
 573                 }
 574                 switch (req.property) {
 575                 case UBI_PROP_DIRECT_WRITE:
 576                         mutex_lock(&ubi->device_mutex);
 577                         desc->vol->direct_writes = !!req.value;
 578                         mutex_unlock(&ubi->device_mutex);
 579                         break;
 580                 default:
 581                         err = -EINVAL;
 582                         break;
 583                 }
 584                 break;
 585         }
 586
 587         default:
 588                 err = -ENOTTY;
 589                 break;
 590         }
 591         return err;
 592 }
 593
 594 /**
 595  * verify_mkvol_req - verify volume creation request.
 596  * @ubi: UBI device description object
 597  * @req: the request to check
 598  *
 599  * This function zero if the request is correct, and %-EINVAL if not.
 600  */
 601 static int verify_mkvol_req(const struct ubi_device *ubi,
 602                             const struct ubi_mkvol_req *req)
 603 {
 604         int n, err = -EINVAL;
 605
 606         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
 607             req->name_len < 0)
 608                 goto bad;
 609
 610         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
 611             req->vol_id != UBI_VOL_NUM_AUTO)
 612                 goto bad;
 613
 614         if (req->alignment == 0)
 615                 goto bad;
 616
 617         if (req->bytes == 0)
 618                 goto bad;
 619
 620         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
 621             req->vol_type != UBI_STATIC_VOLUME)
 622                 goto bad;
 623
 624         if (req->alignment > ubi->leb_size)
 625                 goto bad;
 626
 627         n = req->alignment & (ubi->min_io_size - 1);
 628         if (req->alignment != 1 && n)
 629                 goto bad;
 630
 631         if (req->name_len > UBI_VOL_NAME_MAX) {
 632                 err = -ENAMETOOLONG;
 633                 goto bad;
 634         }
 635
 636         n = strnlen(req->name, req->name_len + 1);
 637         if (n != req->name_len)
 638                 goto bad;
 639
 640         return 0;
 641
 642 bad:
 643         dbg_err("bad volume creation request");
 644         ubi_dbg_dump_mkvol_req(req);
 645         return err;
 646 }
 647
 648 /**
 649  * verify_rsvol_req - verify volume re-size request.
 650  * @ubi: UBI device description object
 651  * @req: the request to check
 652  *
 653  * This function returns zero if the request is correct, and %-EINVAL if not.
 654  */
 655 static int verify_rsvol_req(const struct ubi_device *ubi,
 656                             const struct ubi_rsvol_req *req)
 657 {
 658         if (req->bytes <= 0)
 659                 return -EINVAL;
 660
 661         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
 662                 return -EINVAL;
 663
 664         return 0;
 665 }
 666
 667 /**
 668  * rename_volumes - rename UBI volumes.
 669  * @ubi: UBI device description object
 670  * @req: volumes re-name request
 671  *
 672  * This is a helper function for the volume re-name IOCTL which validates the
 673  * the request, opens the volume and calls corresponding volumes management
 674  * function. Returns zero in case of success and a negative error code in case
 675  * of failure.
 676  */
 677 static int rename_volumes(struct ubi_device *ubi,
 678                           struct ubi_rnvol_req *req)
 679 {
 680         int i, n, err;
 681         struct list_head rename_list;
 682         struct ubi_rename_entry *re, *re1;
 683
 684         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
 685                 return -EINVAL;
 686
 687         if (req->count == 0)
 688                 return 0;
 689
 690         /* Validate volume IDs and names in the request */
 691         for (i = 0; i < req->count; i++) {
 692                 if (req->ents[i].vol_id < 0 ||
 693                     req->ents[i].vol_id >= ubi->vtbl_slots)
 694                         return -EINVAL;
 695                 if (req->ents[i].name_len < 0)
 696                         return -EINVAL;
 697                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
 698                         return -ENAMETOOLONG;
 699                 req->ents[i].name[req->ents[i].name_len] = '\0';
 700                 n = strlen(req->ents[i].name);
 701                 if (n != req->ents[i].name_len)
 702                         err = -EINVAL;
 703         }
 704
 705         /* Make sure volume IDs and names are unique */
 706         for (i = 0; i < req->count - 1; i++) {
 707                 for (n = i + 1; n < req->count; n++) {
 708                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
 709                                 dbg_err("duplicated volume id %d",
 710                                         req->ents[i].vol_id);
 711                                 return -EINVAL;
 712                         }
 713                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
 714                                 dbg_err("duplicated volume name \"%s\"",
 715                                         req->ents[i].name);
 716                                 return -EINVAL;
 717                         }
 718                 }
 719         }
 720
 721         /* Create the re-name list */
 722         INIT_LIST_HEAD(&rename_list);
 723         for (i = 0; i < req->count; i++) {
 724                 int vol_id = req->ents[i].vol_id;
 725                 int name_len = req->ents[i].name_len;
 726                 const char *name = req->ents[i].name;
 727
 728                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 729                 if (!re) {
 730                         err = -ENOMEM;
 731                         goto out_free;
 732                 }
 733
 734                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 735                 if (IS_ERR(re->desc)) {
 736                         err = PTR_ERR(re->desc);
 737                         dbg_err("cannot open volume %d, error %d", vol_id, err);
 738                         kfree(re);
 739                         goto out_free;
 740                 }
 741
 742                 /* Skip this re-naming if the name does not really change */
 743                 if (re->desc->vol->name_len == name_len &&
 744                     !memcmp(re->desc->vol->name, name, name_len)) {
 745                         ubi_close_volume(re->desc);
 746                         kfree(re);
 747                         continue;
 748                 }
 749
 750                 re->new_name_len = name_len;
 751                 memcpy(re->new_name, name, name_len);
 752                 list_add_tail(&re->list, &rename_list);
 753                 dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
 754                         vol_id, re->desc->vol->name, name);
 755         }
 756
 757         if (list_empty(&rename_list))
 758                 return 0;
 759
 760         /* Find out the volumes which have to be removed */
 761         list_for_each_entry(re, &rename_list, list) {
 762                 struct ubi_volume_desc *desc;
 763                 int no_remove_needed = 0;
 764
 765                 /*
 766                  * Volume @re->vol_id is going to be re-named to
 767                  * @re->new_name, while its current name is @name. If a volume
 768                  * with name @re->new_name currently exists, it has to be
 769                  * removed, unless it is also re-named in the request (@req).
 770                  */
 771                 list_for_each_entry(re1, &rename_list, list) {
 772                         if (re->new_name_len == re1->desc->vol->name_len &&
 773                             !memcmp(re->new_name, re1->desc->vol->name,
 774                                     re1->desc->vol->name_len)) {
 775                                 no_remove_needed = 1;
 776                                 break;
 777                         }
 778                 }
 779
 780                 if (no_remove_needed)
 781                         continue;
 782
 783                 /*
 784                  * It seems we need to remove volume with name @re->new_name,
 785                  * if it exists.
 786                  */
 787                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
 788                                           UBI_EXCLUSIVE);
 789                 if (IS_ERR(desc)) {
 790                         err = PTR_ERR(desc);
 791                         if (err == -ENODEV)
 792                                 /* Re-naming into a non-existing volume name */
 793                                 continue;
 794
 795                         /* The volume exists but busy, or an error occurred */
 796                         dbg_err("cannot open volume \"%s\", error %d",
 797                                 re->new_name, err);
 798                         goto out_free;
 799                 }
 800
 801                 re1 = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 802                 if (!re1) {
 803                         err = -ENOMEM;
 804                         ubi_close_volume(desc);
 805                         goto out_free;
 806                 }
 807
 808                 re1->remove = 1;
 809                 re1->desc = desc;
 810                 list_add(&re1->list, &rename_list);
 811                 dbg_msg("will remove volume %d, name \"%s\"",
 812                         re1->desc->vol->vol_id, re1->desc->vol->name);
 813         }
 814
 815         mutex_lock(&ubi->device_mutex);
 816         err = ubi_rename_volumes(ubi, &rename_list);
 817         mutex_unlock(&ubi->device_mutex);
 818
 819 out_free:
 820         list_for_each_entry_safe(re, re1, &rename_list, list) {
 821                 ubi_close_volume(re->desc);
 822                 list_del(&re->list);
 823                 kfree(re);
 824         }
 825         return err;
 826 }
 827
 828 static long ubi_cdev_ioctl(struct file *file, unsigned int cmd,
 829                            unsigned long arg)
 830 {
 831         int err = 0;
 832         struct ubi_device *ubi;
 833         struct ubi_volume_desc *desc;
 834         void __user *argp = (void __user *)arg;
 835
 836         if (!capable(CAP_SYS_RESOURCE))
 837                 return -EPERM;
 838
 839         ubi = ubi_get_by_major(imajor(file->f_mapping->host));
 840         if (!ubi)
 841                 return -ENODEV;
 842
 843         switch (cmd) {
 844         /* Create volume command */
 845         case UBI_IOCMKVOL:
 846         {
 847                 struct ubi_mkvol_req req;
 848
 849                 dbg_gen("create volume");
 850                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
 851                 if (err) {
 852                         err = -EFAULT;
 853                         break;
 854                 }
 855
 856                 err = verify_mkvol_req(ubi, &req);
 857                 if (err)
 858                         break;
 859
 860                 mutex_lock(&ubi->device_mutex);
 861                 err = ubi_create_volume(ubi, &req);
 862                 mutex_unlock(&ubi->device_mutex);
 863                 if (err)
 864                         break;
 865
 866                 err = put_user(req.vol_id, (__user int32_t *)argp);
 867                 if (err)
 868                         err = -EFAULT;
 869
 870                 break;
 871         }
 872
 873         /* Remove volume command */
 874         case UBI_IOCRMVOL:
 875         {
 876                 int vol_id;
 877
 878                 dbg_gen("remove volume");
 879                 err = get_user(vol_id, (__user int32_t *)argp);
 880                 if (err) {
 881                         err = -EFAULT;
 882                         break;
 883                 }
 884
 885                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 886                 if (IS_ERR(desc)) {
 887                         err = PTR_ERR(desc);
 888                         break;
 889                 }
 890
 891                 mutex_lock(&ubi->device_mutex);
 892                 err = ubi_remove_volume(desc, 0);
 893                 mutex_unlock(&ubi->device_mutex);
 894
 895                 /*
 896                  * The volume is deleted (unless an error occurred), and the
 897                  * 'struct ubi_volume' object will be freed when
 898                  * 'ubi_close_volume()' will call 'put_device()'.
 899                  */
 900                 ubi_close_volume(desc);
 901                 break;
 902         }
 903
 904         /* Re-size volume command */
 905         case UBI_IOCRSVOL:
 906         {
 907                 int pebs;
 908                 struct ubi_rsvol_req req;
 909
 910                 dbg_gen("re-size volume");
 911                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
 912                 if (err) {
 913                         err = -EFAULT;
 914                         break;
 915                 }
 916
 917                 err = verify_rsvol_req(ubi, &req);
 918                 if (err)
 919                         break;
 920
 921                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
 922                 if (IS_ERR(desc)) {
 923                         err = PTR_ERR(desc);
 924                         break;
 925                 }
 926
 927                 pebs = div_u64(req.bytes + desc->vol->usable_leb_size - 1,
 928                                desc->vol->usable_leb_size);
 929
 930                 mutex_lock(&ubi->device_mutex);
 931                 err = ubi_resize_volume(desc, pebs);
 932                 mutex_unlock(&ubi->device_mutex);
 933                 ubi_close_volume(desc);
 934                 break;
 935         }
 936
 937         /* Re-name volumes command */
 938         case UBI_IOCRNVOL:
 939         {
 940                 struct ubi_rnvol_req *req;
 941
 942                 dbg_msg("re-name volumes");
 943                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
 944                 if (!req) {
 945                         err = -ENOMEM;
 946                         break;
 947                 };
 948
 949                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
 950                 if (err) {
 951                         err = -EFAULT;
 952                         kfree(req);
 953                         break;
 954                 }
 955
 956                 err = rename_volumes(ubi, req);
 957                 kfree(req);
 958                 break;
 959         }
 960
 961         default:
 962                 err = -ENOTTY;
 963                 break;
 964         }
 965
 966         ubi_put_device(ubi);
 967         return err;
 968 }
 969
 970 static long ctrl_cdev_ioctl(struct file *file, unsigned int cmd,
 971                             unsigned long arg)
 972 {
 973         int err = 0;
 974         void __user *argp = (void __user *)arg;
 975
 976         if (!capable(CAP_SYS_RESOURCE))
 977                 return -EPERM;
 978
 979         switch (cmd) {
 980         /* Attach an MTD device command */
 981         case UBI_IOCATT:
 982         {
 983                 struct ubi_attach_req req;
 984                 struct mtd_info *mtd;
 985
 986                 dbg_gen("attach MTD device");
 987                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
 988                 if (err) {
 989                         err = -EFAULT;
 990                         break;
 991                 }
 992
 993                 if (req.mtd_num < 0 ||
 994                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
 995                         err = -EINVAL;
 996                         break;
 997                 }
 998
 999                 mtd = get_mtd_device(NULL, req.mtd_num);
1000                 if (IS_ERR(mtd)) {
1001                         err = PTR_ERR(mtd);
1002                         break;
1003                 }
1004
1005                 /*
1006                  * Note, further request verification is done by
1007                  * 'ubi_attach_mtd_dev()'.
1008                  */
1009                 mutex_lock(&ubi_devices_mutex);
1010                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
1011                 mutex_unlock(&ubi_devices_mutex);
1012                 if (err < 0)
1013                         put_mtd_device(mtd);
1014                 else
1015                         /* @err contains UBI device number */
1016                         err = put_user(err, (__user int32_t *)argp);
1017
1018                 break;
1019         }
1020
1021         /* Detach an MTD device command */
1022         case UBI_IOCDET:
1023         {
1024                 int ubi_num;
1025
1026                 dbg_gen("dettach MTD device");
1027                 err = get_user(ubi_num, (__user int32_t *)argp);
1028                 if (err) {
1029                         err = -EFAULT;
1030                         break;
1031                 }
1032
1033                 mutex_lock(&ubi_devices_mutex);
1034                 err = ubi_detach_mtd_dev(ubi_num, 0);
1035                 mutex_unlock(&ubi_devices_mutex);
1036                 break;
1037         }
1038
1039         default:
1040                 err = -ENOTTY;
1041                 break;
1042         }
1043
1044         return err;
1045 }
1046
1047 #ifdef CONFIG_COMPAT
1048 static long vol_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1049                                   unsigned long arg)
1050 {
1051         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1052
1053         return vol_cdev_ioctl(file, cmd, translated_arg);
1054 }
1055
1056 static long ubi_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1057                                   unsigned long arg)
1058 {
1059         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1060
1061         return ubi_cdev_ioctl(file, cmd, translated_arg);
1062 }
1063
1064 static long ctrl_cdev_compat_ioctl(struct file *file, unsigned int cmd,
1065                                    unsigned long arg)
1066 {
1067         unsigned long translated_arg = (unsigned long)compat_ptr(arg);
1068
1069         return ctrl_cdev_ioctl(file, cmd, translated_arg);
1070 }
1071 #else
1072 #define vol_cdev_compat_ioctl  NULL
1073 #define ubi_cdev_compat_ioctl  NULL
1074 #define ctrl_cdev_compat_ioctl NULL
1075 #endif
1076
1077 /* UBI volume character device operations */
1078 const struct file_operations ubi_vol_cdev_operations = {
1079         .owner          = THIS_MODULE,
1080         .open           = vol_cdev_open,
1081         .release        = vol_cdev_release,
1082         .llseek         = vol_cdev_llseek,
1083         .read           = vol_cdev_read,
1084         .write          = vol_cdev_write,
1085         .fsync          = vol_cdev_fsync,
1086         .unlocked_ioctl = vol_cdev_ioctl,
1087         .compat_ioctl   = vol_cdev_compat_ioctl,
1088 };
1089
1090 /* UBI character device operations */
1091 const struct file_operations ubi_cdev_operations = {
1092         .owner          = THIS_MODULE,
1093         .llseek         = no_llseek,
1094         .unlocked_ioctl = ubi_cdev_ioctl,
1095         .compat_ioctl   = ubi_cdev_compat_ioctl,
1096 };
1097
1098 /* UBI control character device operations */
1099 const struct file_operations ubi_ctrl_cdev_operations = {
1100         .owner          = THIS_MODULE,
1101         .unlocked_ioctl = ctrl_cdev_ioctl,
1102         .compat_ioctl   = ctrl_cdev_compat_ioctl,
1103         .llseek         = noop_llseek,
1104 };