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/ioctl.h>
  41 #include <linux/capability.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/smp_lock.h>
  44 #include <mtd/ubi-user.h>
  45 #include <asm/div64.h>
  46 #include "ubi.h"
  47
  48 /**
  49  * get_exclusive - get exclusive access to an UBI volume.
  50  * @desc: volume descriptor
  51  *
  52  * This function changes UBI volume open mode to "exclusive". Returns previous
  53  * mode value (positive integer) in case of success and a negative error code
  54  * in case of failure.
  55  */
  56 static int get_exclusive(struct ubi_volume_desc *desc)
  57 {
  58         int users, err;
  59         struct ubi_volume *vol = desc->vol;
  60
  61         spin_lock(&vol->ubi->volumes_lock);
  62         users = vol->readers + vol->writers + vol->exclusive;
  63         ubi_assert(users > 0);
  64         if (users > 1) {
  65                 dbg_err("%d users for volume %d", users, vol->vol_id);
  66                 err = -EBUSY;
  67         } else {
  68                 vol->readers = vol->writers = 0;
  69                 vol->exclusive = 1;
  70                 err = desc->mode;
  71                 desc->mode = UBI_EXCLUSIVE;
  72         }
  73         spin_unlock(&vol->ubi->volumes_lock);
  74
  75         return err;
  76 }
  77
  78 /**
  79  * revoke_exclusive - revoke exclusive mode.
  80  * @desc: volume descriptor
  81  * @mode: new mode to switch to
  82  */
  83 static void revoke_exclusive(struct ubi_volume_desc *desc, int mode)
  84 {
  85         struct ubi_volume *vol = desc->vol;
  86
  87         spin_lock(&vol->ubi->volumes_lock);
  88         ubi_assert(vol->readers == 0 && vol->writers == 0);
  89         ubi_assert(vol->exclusive == 1 && desc->mode == UBI_EXCLUSIVE);
  90         vol->exclusive = 0;
  91         if (mode == UBI_READONLY)
  92                 vol->readers = 1;
  93         else if (mode == UBI_READWRITE)
  94                 vol->writers = 1;
  95         else
  96                 vol->exclusive = 1;
  97         spin_unlock(&vol->ubi->volumes_lock);
  98
  99         desc->mode = mode;
 100 }
 101
 102 static int vol_cdev_open(struct inode *inode, struct file *file)
 103 {
 104         struct ubi_volume_desc *desc;
 105         int vol_id = iminor(inode) - 1, mode, ubi_num;
 106
 107         ubi_num = ubi_major2num(imajor(inode));
 108         if (ubi_num < 0)
 109                 return ubi_num;
 110
 111         if (file->f_mode & FMODE_WRITE)
 112                 mode = UBI_READWRITE;
 113         else
 114                 mode = UBI_READONLY;
 115
 116         dbg_gen("open volume %d, mode %d", vol_id, mode);
 117
 118         desc = ubi_open_volume(ubi_num, vol_id, mode);
 119         if (IS_ERR(desc))
 120                 return PTR_ERR(desc);
 121
 122         file->private_data = desc;
 123         return 0;
 124 }
 125
 126 static int vol_cdev_release(struct inode *inode, struct file *file)
 127 {
 128         struct ubi_volume_desc *desc = file->private_data;
 129         struct ubi_volume *vol = desc->vol;
 130
 131         dbg_gen("release volume %d, mode %d", vol->vol_id, desc->mode);
 132
 133         if (vol->updating) {
 134                 ubi_warn("update of volume %d not finished, volume is damaged",
 135                          vol->vol_id);
 136                 ubi_assert(!vol->changing_leb);
 137                 vol->updating = 0;
 138                 vfree(vol->upd_buf);
 139         } else if (vol->changing_leb) {
 140                 dbg_gen("only %lld of %lld bytes received for atomic LEB change"
 141                         " for volume %d:%d, cancel", vol->upd_received,
 142                         vol->upd_bytes, vol->ubi->ubi_num, vol->vol_id);
 143                 vol->changing_leb = 0;
 144                 vfree(vol->upd_buf);
 145         }
 146
 147         ubi_close_volume(desc);
 148         return 0;
 149 }
 150
 151 static loff_t vol_cdev_llseek(struct file *file, loff_t offset, int origin)
 152 {
 153         struct ubi_volume_desc *desc = file->private_data;
 154         struct ubi_volume *vol = desc->vol;
 155         loff_t new_offset;
 156
 157         if (vol->updating) {
 158                  /* Update is in progress, seeking is prohibited */
 159                 dbg_err("updating");
 160                 return -EBUSY;
 161         }
 162
 163         switch (origin) {
 164         case 0: /* SEEK_SET */
 165                 new_offset = offset;
 166                 break;
 167         case 1: /* SEEK_CUR */
 168                 new_offset = file->f_pos + offset;
 169                 break;
 170         case 2: /* SEEK_END */
 171                 new_offset = vol->used_bytes + offset;
 172                 break;
 173         default:
 174                 return -EINVAL;
 175         }
 176
 177         if (new_offset < 0 || new_offset > vol->used_bytes) {
 178                 dbg_err("bad seek %lld", new_offset);
 179                 return -EINVAL;
 180         }
 181
 182         dbg_gen("seek volume %d, offset %lld, origin %d, new offset %lld",
 183                 vol->vol_id, offset, origin, new_offset);
 184
 185         file->f_pos = new_offset;
 186         return new_offset;
 187 }
 188
 189 static ssize_t vol_cdev_read(struct file *file, __user char *buf, size_t count,
 190                              loff_t *offp)
 191 {
 192         struct ubi_volume_desc *desc = file->private_data;
 193         struct ubi_volume *vol = desc->vol;
 194         struct ubi_device *ubi = vol->ubi;
 195         int err, lnum, off, len,  tbuf_size;
 196         size_t count_save = count;
 197         void *tbuf;
 198         uint64_t tmp;
 199
 200         dbg_gen("read %zd bytes from offset %lld of volume %d",
 201                 count, *offp, vol->vol_id);
 202
 203         if (vol->updating) {
 204                 dbg_err("updating");
 205                 return -EBUSY;
 206         }
 207         if (vol->upd_marker) {
 208                 dbg_err("damaged volume, update marker is set");
 209                 return -EBADF;
 210         }
 211         if (*offp == vol->used_bytes || count == 0)
 212                 return 0;
 213
 214         if (vol->corrupted)
 215                 dbg_gen("read from corrupted volume %d", vol->vol_id);
 216
 217         if (*offp + count > vol->used_bytes)
 218                 count_save = count = vol->used_bytes - *offp;
 219
 220         tbuf_size = vol->usable_leb_size;
 221         if (count < tbuf_size)
 222                 tbuf_size = ALIGN(count, ubi->min_io_size);
 223         tbuf = vmalloc(tbuf_size);
 224         if (!tbuf)
 225                 return -ENOMEM;
 226
 227         len = count > tbuf_size ? tbuf_size : count;
 228
 229         tmp = *offp;
 230         off = do_div(tmp, vol->usable_leb_size);
 231         lnum = tmp;
 232
 233         do {
 234                 cond_resched();
 235
 236                 if (off + len >= vol->usable_leb_size)
 237                         len = vol->usable_leb_size - off;
 238
 239                 err = ubi_eba_read_leb(ubi, vol, lnum, tbuf, off, len, 0);
 240                 if (err)
 241                         break;
 242
 243                 off += len;
 244                 if (off == vol->usable_leb_size) {
 245                         lnum += 1;
 246                         off -= vol->usable_leb_size;
 247                 }
 248
 249                 count -= len;
 250                 *offp += len;
 251
 252                 err = copy_to_user(buf, tbuf, len);
 253                 if (err) {
 254                         err = -EFAULT;
 255                         break;
 256                 }
 257
 258                 buf += len;
 259                 len = count > tbuf_size ? tbuf_size : count;
 260         } while (count);
 261
 262         vfree(tbuf);
 263         return err ? err : count_save - count;
 264 }
 265
 266 #ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
 267
 268 /*
 269  * This function allows to directly write to dynamic UBI volumes, without
 270  * issuing the volume update operation. Available only as a debugging feature.
 271  * Very useful for testing UBI.
 272  */
 273 static ssize_t vol_cdev_direct_write(struct file *file, const char __user *buf,
 274                                      size_t count, loff_t *offp)
 275 {
 276         struct ubi_volume_desc *desc = file->private_data;
 277         struct ubi_volume *vol = desc->vol;
 278         struct ubi_device *ubi = vol->ubi;
 279         int lnum, off, len, tbuf_size, err = 0;
 280         size_t count_save = count;
 281         char *tbuf;
 282         uint64_t tmp;
 283
 284         dbg_gen("requested: write %zd bytes to offset %lld of volume %u",
 285                 count, *offp, vol->vol_id);
 286
 287         if (vol->vol_type == UBI_STATIC_VOLUME)
 288                 return -EROFS;
 289
 290         tmp = *offp;
 291         off = do_div(tmp, vol->usable_leb_size);
 292         lnum = tmp;
 293
 294         if (off & (ubi->min_io_size - 1)) {
 295                 dbg_err("unaligned position");
 296                 return -EINVAL;
 297         }
 298
 299         if (*offp + count > vol->used_bytes)
 300                 count_save = count = vol->used_bytes - *offp;
 301
 302         /* We can write only in fractions of the minimum I/O unit */
 303         if (count & (ubi->min_io_size - 1)) {
 304                 dbg_err("unaligned write length");
 305                 return -EINVAL;
 306         }
 307
 308         tbuf_size = vol->usable_leb_size;
 309         if (count < tbuf_size)
 310                 tbuf_size = ALIGN(count, ubi->min_io_size);
 311         tbuf = vmalloc(tbuf_size);
 312         if (!tbuf)
 313                 return -ENOMEM;
 314
 315         len = count > tbuf_size ? tbuf_size : count;
 316
 317         while (count) {
 318                 cond_resched();
 319
 320                 if (off + len >= vol->usable_leb_size)
 321                         len = vol->usable_leb_size - off;
 322
 323                 err = copy_from_user(tbuf, buf, len);
 324                 if (err) {
 325                         err = -EFAULT;
 326                         break;
 327                 }
 328
 329                 err = ubi_eba_write_leb(ubi, vol, lnum, tbuf, off, len,
 330                                         UBI_UNKNOWN);
 331                 if (err)
 332                         break;
 333
 334                 off += len;
 335                 if (off == vol->usable_leb_size) {
 336                         lnum += 1;
 337                         off -= vol->usable_leb_size;
 338                 }
 339
 340                 count -= len;
 341                 *offp += len;
 342                 buf += len;
 343                 len = count > tbuf_size ? tbuf_size : count;
 344         }
 345
 346         vfree(tbuf);
 347         return err ? err : count_save - count;
 348 }
 349
 350 #else
 351 #define vol_cdev_direct_write(file, buf, count, offp) (-EPERM)
 352 #endif /* CONFIG_MTD_UBI_DEBUG_USERSPACE_IO */
 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_gluebi_updated(vol);
 399                 revoke_exclusive(desc, UBI_READWRITE);
 400         }
 401
 402         return count;
 403 }
 404
 405 static int vol_cdev_ioctl(struct inode *inode, struct file *file,
 406                           unsigned int cmd, 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 #ifdef CONFIG_MTD_UBI_DEBUG_USERSPACE_IO
 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 #endif
 522
 523         default:
 524                 err = -ENOTTY;
 525                 break;
 526         }
 527
 528         return err;
 529 }
 530
 531 /**
 532  * verify_mkvol_req - verify volume creation request.
 533  * @ubi: UBI device description object
 534  * @req: the request to check
 535  *
 536  * This function zero if the request is correct, and %-EINVAL if not.
 537  */
 538 static int verify_mkvol_req(const struct ubi_device *ubi,
 539                             const struct ubi_mkvol_req *req)
 540 {
 541         int n, err = -EINVAL;
 542
 543         if (req->bytes < 0 || req->alignment < 0 || req->vol_type < 0 ||
 544             req->name_len < 0)
 545                 goto bad;
 546
 547         if ((req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots) &&
 548             req->vol_id != UBI_VOL_NUM_AUTO)
 549                 goto bad;
 550
 551         if (req->alignment == 0)
 552                 goto bad;
 553
 554         if (req->bytes == 0)
 555                 goto bad;
 556
 557         if (req->vol_type != UBI_DYNAMIC_VOLUME &&
 558             req->vol_type != UBI_STATIC_VOLUME)
 559                 goto bad;
 560
 561         if (req->alignment > ubi->leb_size)
 562                 goto bad;
 563
 564         n = req->alignment & (ubi->min_io_size - 1);
 565         if (req->alignment != 1 && n)
 566                 goto bad;
 567
 568         if (req->name_len > UBI_VOL_NAME_MAX) {
 569                 err = -ENAMETOOLONG;
 570                 goto bad;
 571         }
 572
 573         n = strnlen(req->name, req->name_len + 1);
 574         if (n != req->name_len)
 575                 goto bad;
 576
 577         return 0;
 578
 579 bad:
 580         dbg_err("bad volume creation request");
 581         ubi_dbg_dump_mkvol_req(req);
 582         return err;
 583 }
 584
 585 /**
 586  * verify_rsvol_req - verify volume re-size request.
 587  * @ubi: UBI device description object
 588  * @req: the request to check
 589  *
 590  * This function returns zero if the request is correct, and %-EINVAL if not.
 591  */
 592 static int verify_rsvol_req(const struct ubi_device *ubi,
 593                             const struct ubi_rsvol_req *req)
 594 {
 595         if (req->bytes <= 0)
 596                 return -EINVAL;
 597
 598         if (req->vol_id < 0 || req->vol_id >= ubi->vtbl_slots)
 599                 return -EINVAL;
 600
 601         return 0;
 602 }
 603
 604 /**
 605  * rename_volumes - rename UBI volumes.
 606  * @ubi: UBI device description object
 607  * @req: volumes re-name request
 608  *
 609  * This is a helper function for the volume re-name IOCTL which validates the
 610  * the request, opens the volume and calls corresponding volumes management
 611  * function. Returns zero in case of success and a negative error code in case
 612  * of failure.
 613  */
 614 static int rename_volumes(struct ubi_device *ubi,
 615                           struct ubi_rnvol_req *req)
 616 {
 617         int i, n, err;
 618         struct list_head rename_list;
 619         struct ubi_rename_entry *re, *re1;
 620
 621         if (req->count < 0 || req->count > UBI_MAX_RNVOL)
 622                 return -EINVAL;
 623
 624         if (req->count == 0)
 625                 return 0;
 626
 627         /* Validate volume IDs and names in the request */
 628         for (i = 0; i < req->count; i++) {
 629                 if (req->ents[i].vol_id < 0 ||
 630                     req->ents[i].vol_id >= ubi->vtbl_slots)
 631                         return -EINVAL;
 632                 if (req->ents[i].name_len < 0)
 633                         return -EINVAL;
 634                 if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
 635                         return -ENAMETOOLONG;
 636                 req->ents[i].name[req->ents[i].name_len] = '\0';
 637                 n = strlen(req->ents[i].name);
 638                 if (n != req->ents[i].name_len)
 639                         err = -EINVAL;
 640         }
 641
 642         /* Make sure volume IDs and names are unique */
 643         for (i = 0; i < req->count - 1; i++) {
 644                 for (n = i + 1; n < req->count; n++) {
 645                         if (req->ents[i].vol_id == req->ents[n].vol_id) {
 646                                 dbg_err("duplicated volume id %d",
 647                                         req->ents[i].vol_id);
 648                                 return -EINVAL;
 649                         }
 650                         if (!strcmp(req->ents[i].name, req->ents[n].name)) {
 651                                 dbg_err("duplicated volume name \"%s\"",
 652                                         req->ents[i].name);
 653                                 return -EINVAL;
 654                         }
 655                 }
 656         }
 657
 658         /* Create the re-name list */
 659         INIT_LIST_HEAD(&rename_list);
 660         for (i = 0; i < req->count; i++) {
 661                 int vol_id = req->ents[i].vol_id;
 662                 int name_len = req->ents[i].name_len;
 663                 const char *name = req->ents[i].name;
 664
 665                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 666                 if (!re) {
 667                         err = -ENOMEM;
 668                         goto out_free;
 669                 }
 670
 671                 re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 672                 if (IS_ERR(re->desc)) {
 673                         err = PTR_ERR(re->desc);
 674                         dbg_err("cannot open volume %d, error %d", vol_id, err);
 675                         kfree(re);
 676                         goto out_free;
 677                 }
 678
 679                 /* Skip this re-naming if the name does not really change */
 680                 if (re->desc->vol->name_len == name_len &&
 681                     !memcmp(re->desc->vol->name, name, name_len)) {
 682                         ubi_close_volume(re->desc);
 683                         kfree(re);
 684                         continue;
 685                 }
 686
 687                 re->new_name_len = name_len;
 688                 memcpy(re->new_name, name, name_len);
 689                 list_add_tail(&re->list, &rename_list);
 690                 dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
 691                         vol_id, re->desc->vol->name, name);
 692         }
 693
 694         if (list_empty(&rename_list))
 695                 return 0;
 696
 697         /* Find out the volumes which have to be removed */
 698         list_for_each_entry(re, &rename_list, list) {
 699                 struct ubi_volume_desc *desc;
 700                 int no_remove_needed = 0;
 701
 702                 /*
 703                  * Volume @re->vol_id is going to be re-named to
 704                  * @re->new_name, while its current name is @name. If a volume
 705                  * with name @re->new_name currently exists, it has to be
 706                  * removed, unless it is also re-named in the request (@req).
 707                  */
 708                 list_for_each_entry(re1, &rename_list, list) {
 709                         if (re->new_name_len == re1->desc->vol->name_len &&
 710                             !memcmp(re->new_name, re1->desc->vol->name,
 711                                     re1->desc->vol->name_len)) {
 712                                 no_remove_needed = 1;
 713                                 break;
 714                         }
 715                 }
 716
 717                 if (no_remove_needed)
 718                         continue;
 719
 720                 /*
 721                  * It seems we need to remove volume with name @re->new_name,
 722                  * if it exists.
 723                  */
 724                 desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name,
 725                                           UBI_EXCLUSIVE);
 726                 if (IS_ERR(desc)) {
 727                         err = PTR_ERR(desc);
 728                         if (err == -ENODEV)
 729                                 /* Re-naming into a non-existing volume name */
 730                                 continue;
 731
 732                         /* The volume exists but busy, or an error occurred */
 733                         dbg_err("cannot open volume \"%s\", error %d",
 734                                 re->new_name, err);
 735                         goto out_free;
 736                 }
 737
 738                 re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
 739                 if (!re) {
 740                         err = -ENOMEM;
 741                         ubi_close_volume(desc);
 742                         goto out_free;
 743                 }
 744
 745                 re->remove = 1;
 746                 re->desc = desc;
 747                 list_add(&re->list, &rename_list);
 748                 dbg_msg("will remove volume %d, name \"%s\"",
 749                         re->desc->vol->vol_id, re->desc->vol->name);
 750         }
 751
 752         mutex_lock(&ubi->volumes_mutex);
 753         err = ubi_rename_volumes(ubi, &rename_list);
 754         mutex_unlock(&ubi->volumes_mutex);
 755
 756 out_free:
 757         list_for_each_entry_safe(re, re1, &rename_list, list) {
 758                 ubi_close_volume(re->desc);
 759                 list_del(&re->list);
 760                 kfree(re);
 761         }
 762         return err;
 763 }
 764
 765 static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
 766                           unsigned int cmd, unsigned long arg)
 767 {
 768         int err = 0;
 769         struct ubi_device *ubi;
 770         struct ubi_volume_desc *desc;
 771         void __user *argp = (void __user *)arg;
 772
 773         if (!capable(CAP_SYS_RESOURCE))
 774                 return -EPERM;
 775
 776         ubi = ubi_get_by_major(imajor(inode));
 777         if (!ubi)
 778                 return -ENODEV;
 779
 780         switch (cmd) {
 781         /* Create volume command */
 782         case UBI_IOCMKVOL:
 783         {
 784                 struct ubi_mkvol_req req;
 785
 786                 dbg_gen("create volume");
 787                 err = copy_from_user(&req, argp, sizeof(struct ubi_mkvol_req));
 788                 if (err) {
 789                         err = -EFAULT;
 790                         break;
 791                 }
 792
 793                 req.name[req.name_len] = '\0';
 794                 err = verify_mkvol_req(ubi, &req);
 795                 if (err)
 796                         break;
 797
 798                 mutex_lock(&ubi->volumes_mutex);
 799                 err = ubi_create_volume(ubi, &req);
 800                 mutex_unlock(&ubi->volumes_mutex);
 801                 if (err)
 802                         break;
 803
 804                 err = put_user(req.vol_id, (__user int32_t *)argp);
 805                 if (err)
 806                         err = -EFAULT;
 807
 808                 break;
 809         }
 810
 811         /* Remove volume command */
 812         case UBI_IOCRMVOL:
 813         {
 814                 int vol_id;
 815
 816                 dbg_gen("remove volume");
 817                 err = get_user(vol_id, (__user int32_t *)argp);
 818                 if (err) {
 819                         err = -EFAULT;
 820                         break;
 821                 }
 822
 823                 desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
 824                 if (IS_ERR(desc)) {
 825                         err = PTR_ERR(desc);
 826                         break;
 827                 }
 828
 829                 mutex_lock(&ubi->volumes_mutex);
 830                 err = ubi_remove_volume(desc, 0);
 831                 mutex_unlock(&ubi->volumes_mutex);
 832
 833                 /*
 834                  * The volume is deleted (unless an error occurred), and the
 835                  * 'struct ubi_volume' object will be freed when
 836                  * 'ubi_close_volume()' will call 'put_device()'.
 837                  */
 838                 ubi_close_volume(desc);
 839                 break;
 840         }
 841
 842         /* Re-size volume command */
 843         case UBI_IOCRSVOL:
 844         {
 845                 int pebs;
 846                 uint64_t tmp;
 847                 struct ubi_rsvol_req req;
 848
 849                 dbg_gen("re-size volume");
 850                 err = copy_from_user(&req, argp, sizeof(struct ubi_rsvol_req));
 851                 if (err) {
 852                         err = -EFAULT;
 853                         break;
 854                 }
 855
 856                 err = verify_rsvol_req(ubi, &req);
 857                 if (err)
 858                         break;
 859
 860                 desc = ubi_open_volume(ubi->ubi_num, req.vol_id, UBI_EXCLUSIVE);
 861                 if (IS_ERR(desc)) {
 862                         err = PTR_ERR(desc);
 863                         break;
 864                 }
 865
 866                 tmp = req.bytes;
 867                 pebs = !!do_div(tmp, desc->vol->usable_leb_size);
 868                 pebs += tmp;
 869
 870                 mutex_lock(&ubi->volumes_mutex);
 871                 err = ubi_resize_volume(desc, pebs);
 872                 mutex_unlock(&ubi->volumes_mutex);
 873                 ubi_close_volume(desc);
 874                 break;
 875         }
 876
 877         /* Re-name volumes command */
 878         case UBI_IOCRNVOL:
 879         {
 880                 struct ubi_rnvol_req *req;
 881
 882                 dbg_msg("re-name volumes");
 883                 req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
 884                 if (!req) {
 885                         err = -ENOMEM;
 886                         break;
 887                 };
 888
 889                 err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
 890                 if (err) {
 891                         err = -EFAULT;
 892                         kfree(req);
 893                         break;
 894                 }
 895
 896                 mutex_lock(&ubi->mult_mutex);
 897                 err = rename_volumes(ubi, req);
 898                 mutex_unlock(&ubi->mult_mutex);
 899                 kfree(req);
 900                 break;
 901         }
 902
 903         default:
 904                 err = -ENOTTY;
 905                 break;
 906         }
 907
 908         ubi_put_device(ubi);
 909         return err;
 910 }
 911
 912 static int ctrl_cdev_ioctl(struct inode *inode, struct file *file,
 913                            unsigned int cmd, unsigned long arg)
 914 {
 915         int err = 0;
 916         void __user *argp = (void __user *)arg;
 917
 918         if (!capable(CAP_SYS_RESOURCE))
 919                 return -EPERM;
 920
 921         switch (cmd) {
 922         /* Attach an MTD device command */
 923         case UBI_IOCATT:
 924         {
 925                 struct ubi_attach_req req;
 926                 struct mtd_info *mtd;
 927
 928                 dbg_gen("attach MTD device");
 929                 err = copy_from_user(&req, argp, sizeof(struct ubi_attach_req));
 930                 if (err) {
 931                         err = -EFAULT;
 932                         break;
 933                 }
 934
 935                 if (req.mtd_num < 0 ||
 936                     (req.ubi_num < 0 && req.ubi_num != UBI_DEV_NUM_AUTO)) {
 937                         err = -EINVAL;
 938                         break;
 939                 }
 940
 941                 mtd = get_mtd_device(NULL, req.mtd_num);
 942                 if (IS_ERR(mtd)) {
 943                         err = PTR_ERR(mtd);
 944                         break;
 945                 }
 946
 947                 /*
 948                  * Note, further request verification is done by
 949                  * 'ubi_attach_mtd_dev()'.
 950                  */
 951                 mutex_lock(&ubi_devices_mutex);
 952                 err = ubi_attach_mtd_dev(mtd, req.ubi_num, req.vid_hdr_offset);
 953                 mutex_unlock(&ubi_devices_mutex);
 954                 if (err < 0)
 955                         put_mtd_device(mtd);
 956                 else
 957                         /* @err contains UBI device number */
 958                         err = put_user(err, (__user int32_t *)argp);
 959
 960                 break;
 961         }
 962
 963         /* Detach an MTD device command */
 964         case UBI_IOCDET:
 965         {
 966                 int ubi_num;
 967
 968                 dbg_gen("dettach MTD device");
 969                 err = get_user(ubi_num, (__user int32_t *)argp);
 970                 if (err) {
 971                         err = -EFAULT;
 972                         break;
 973                 }
 974
 975                 mutex_lock(&ubi_devices_mutex);
 976                 err = ubi_detach_mtd_dev(ubi_num, 0);
 977                 mutex_unlock(&ubi_devices_mutex);
 978                 break;
 979         }
 980
 981         default:
 982                 err = -ENOTTY;
 983                 break;
 984         }
 985
 986         return err;
 987 }
 988
 989 /* UBI control character device operations */
 990 struct file_operations ubi_ctrl_cdev_operations = {
 991         .ioctl = ctrl_cdev_ioctl,
 992         .owner = THIS_MODULE,
 993 };
 994
 995 /* UBI character device operations */
 996 struct file_operations ubi_cdev_operations = {
 997         .owner = THIS_MODULE,
 998         .ioctl = ubi_cdev_ioctl,
 999         .llseek = no_llseek,
1000 };
1001
1002 /* UBI volume character device operations */
1003 struct file_operations ubi_vol_cdev_operations = {
1004         .owner   = THIS_MODULE,
1005         .open    = vol_cdev_open,
1006         .release = vol_cdev_release,
1007         .llseek  = vol_cdev_llseek,
1008         .read    = vol_cdev_read,
1009         .write   = vol_cdev_write,
1010         .ioctl   = vol_cdev_ioctl,
1011 };