drivers/mtd/ubi/kapi.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 /* This file mostly implements UBI kernel API functions */
  22
  23 #include <linux/module.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/namei.h>
  27 #include <linux/fs.h>
  28 #include <asm/div64.h>
  29 #include "ubi.h"
  30
  31 /**
  32  * ubi_do_get_device_info - get information about UBI device.
  33  * @ubi: UBI device description object
  34  * @di: the information is stored here
  35  *
  36  * This function is the same as 'ubi_get_device_info()', but it assumes the UBI
  37  * device is locked and cannot disappear.
  38  */
  39 void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
  40 {
  41         di->ubi_num = ubi->ubi_num;
  42         di->leb_size = ubi->leb_size;
  43         di->leb_start = ubi->leb_start;
  44         di->min_io_size = ubi->min_io_size;
  45         di->max_write_size = ubi->max_write_size;
  46         di->ro_mode = ubi->ro_mode;
  47         di->cdev = ubi->cdev.dev;
  48 }
  49 EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
  50
  51 /**
  52  * ubi_get_device_info - get information about UBI device.
  53  * @ubi_num: UBI device number
  54  * @di: the information is stored here
  55  *
  56  * This function returns %0 in case of success, %-EINVAL if the UBI device
  57  * number is invalid, and %-ENODEV if there is no such UBI device.
  58  */
  59 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
  60 {
  61         struct ubi_device *ubi;
  62
  63         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
  64                 return -EINVAL;
  65         ubi = ubi_get_device(ubi_num);
  66         if (!ubi)
  67                 return -ENODEV;
  68         ubi_do_get_device_info(ubi, di);
  69         ubi_put_device(ubi);
  70         return 0;
  71 }
  72 EXPORT_SYMBOL_GPL(ubi_get_device_info);
  73
  74 /**
  75  * ubi_do_get_volume_info - get information about UBI volume.
  76  * @ubi: UBI device description object
  77  * @vol: volume description object
  78  * @vi: the information is stored here
  79  */
  80 void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
  81                             struct ubi_volume_info *vi)
  82 {
  83         vi->vol_id = vol->vol_id;
  84         vi->ubi_num = ubi->ubi_num;
  85         vi->size = vol->reserved_pebs;
  86         vi->used_bytes = vol->used_bytes;
  87         vi->vol_type = vol->vol_type;
  88         vi->corrupted = vol->corrupted;
  89         vi->upd_marker = vol->upd_marker;
  90         vi->alignment = vol->alignment;
  91         vi->usable_leb_size = vol->usable_leb_size;
  92         vi->name_len = vol->name_len;
  93         vi->name = vol->name;
  94         vi->cdev = vol->cdev.dev;
  95 }
  96
  97 /**
  98  * ubi_get_volume_info - get information about UBI volume.
  99  * @desc: volume descriptor
 100  * @vi: the information is stored here
 101  */
 102 void ubi_get_volume_info(struct ubi_volume_desc *desc,
 103                          struct ubi_volume_info *vi)
 104 {
 105         ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
 106 }
 107 EXPORT_SYMBOL_GPL(ubi_get_volume_info);
 108
 109 /**
 110  * ubi_open_volume - open UBI volume.
 111  * @ubi_num: UBI device number
 112  * @vol_id: volume ID
 113  * @mode: open mode
 114  *
 115  * The @mode parameter specifies if the volume should be opened in read-only
 116  * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
 117  * nobody else will be able to open this volume. UBI allows to have many volume
 118  * readers and one writer at a time.
 119  *
 120  * If a static volume is being opened for the first time since boot, it will be
 121  * checked by this function, which means it will be fully read and the CRC
 122  * checksum of each logical eraseblock will be checked.
 123  *
 124  * This function returns volume descriptor in case of success and a negative
 125  * error code in case of failure.
 126  */
 127 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
 128 {
 129         int err;
 130         struct ubi_volume_desc *desc;
 131         struct ubi_device *ubi;
 132         struct ubi_volume *vol;
 133
 134         dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
 135
 136         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 137                 return ERR_PTR(-EINVAL);
 138
 139         if (mode != UBI_READONLY && mode != UBI_READWRITE &&
 140             mode != UBI_EXCLUSIVE)
 141                 return ERR_PTR(-EINVAL);
 142
 143         /*
 144          * First of all, we have to get the UBI device to prevent its removal.
 145          */
 146         ubi = ubi_get_device(ubi_num);
 147         if (!ubi)
 148                 return ERR_PTR(-ENODEV);
 149
 150         if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
 151                 err = -EINVAL;
 152                 goto out_put_ubi;
 153         }
 154
 155         desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
 156         if (!desc) {
 157                 err = -ENOMEM;
 158                 goto out_put_ubi;
 159         }
 160
 161         err = -ENODEV;
 162         if (!try_module_get(THIS_MODULE))
 163                 goto out_free;
 164
 165         spin_lock(&ubi->volumes_lock);
 166         vol = ubi->volumes[vol_id];
 167         if (!vol)
 168                 goto out_unlock;
 169
 170         err = -EBUSY;
 171         switch (mode) {
 172         case UBI_READONLY:
 173                 if (vol->exclusive)
 174                         goto out_unlock;
 175                 vol->readers += 1;
 176                 break;
 177
 178         case UBI_READWRITE:
 179                 if (vol->exclusive || vol->writers > 0)
 180                         goto out_unlock;
 181                 vol->writers += 1;
 182                 break;
 183
 184         case UBI_EXCLUSIVE:
 185                 if (vol->exclusive || vol->writers || vol->readers)
 186                         goto out_unlock;
 187                 vol->exclusive = 1;
 188                 break;
 189         }
 190         get_device(&vol->dev);
 191         vol->ref_count += 1;
 192         spin_unlock(&ubi->volumes_lock);
 193
 194         desc->vol = vol;
 195         desc->mode = mode;
 196
 197         mutex_lock(&ubi->ckvol_mutex);
 198         if (!vol->checked) {
 199                 /* This is the first open - check the volume */
 200                 err = ubi_check_volume(ubi, vol_id);
 201                 if (err < 0) {
 202                         mutex_unlock(&ubi->ckvol_mutex);
 203                         ubi_close_volume(desc);
 204                         return ERR_PTR(err);
 205                 }
 206                 if (err == 1) {
 207                         ubi_warn("volume %d on UBI device %d is corrupted",
 208                                  vol_id, ubi->ubi_num);
 209                         vol->corrupted = 1;
 210                 }
 211                 vol->checked = 1;
 212         }
 213         mutex_unlock(&ubi->ckvol_mutex);
 214
 215         return desc;
 216
 217 out_unlock:
 218         spin_unlock(&ubi->volumes_lock);
 219         module_put(THIS_MODULE);
 220 out_free:
 221         kfree(desc);
 222 out_put_ubi:
 223         ubi_put_device(ubi);
 224         dbg_err("cannot open device %d, volume %d, error %d",
 225                 ubi_num, vol_id, err);
 226         return ERR_PTR(err);
 227 }
 228 EXPORT_SYMBOL_GPL(ubi_open_volume);
 229
 230 /**
 231  * ubi_open_volume_nm - open UBI volume by name.
 232  * @ubi_num: UBI device number
 233  * @name: volume name
 234  * @mode: open mode
 235  *
 236  * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 237  */
 238 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 239                                            int mode)
 240 {
 241         int i, vol_id = -1, len;
 242         struct ubi_device *ubi;
 243         struct ubi_volume_desc *ret;
 244
 245         dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
 246
 247         if (!name)
 248                 return ERR_PTR(-EINVAL);
 249
 250         len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 251         if (len > UBI_VOL_NAME_MAX)
 252                 return ERR_PTR(-EINVAL);
 253
 254         if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 255                 return ERR_PTR(-EINVAL);
 256
 257         ubi = ubi_get_device(ubi_num);
 258         if (!ubi)
 259                 return ERR_PTR(-ENODEV);
 260
 261         spin_lock(&ubi->volumes_lock);
 262         /* Walk all volumes of this UBI device */
 263         for (i = 0; i < ubi->vtbl_slots; i++) {
 264                 struct ubi_volume *vol = ubi->volumes[i];
 265
 266                 if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 267                         vol_id = i;
 268                         break;
 269                 }
 270         }
 271         spin_unlock(&ubi->volumes_lock);
 272
 273         if (vol_id >= 0)
 274                 ret = ubi_open_volume(ubi_num, vol_id, mode);
 275         else
 276                 ret = ERR_PTR(-ENODEV);
 277
 278         /*
 279          * We should put the UBI device even in case of success, because
 280          * 'ubi_open_volume()' took a reference as well.
 281          */
 282         ubi_put_device(ubi);
 283         return ret;
 284 }
 285 EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 286
 287 /**
 288  * ubi_open_volume_path - open UBI volume by its character device node path.
 289  * @pathname: volume character device node path
 290  * @mode: open mode
 291  *
 292  * This function is similar to 'ubi_open_volume()', but opens a volume the path
 293  * to its character device node.
 294  */
 295 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
 296 {
 297         int error, ubi_num, vol_id, mod;
 298         struct inode *inode;
 299         struct path path;
 300
 301         dbg_gen("open volume %s, mode %d", pathname, mode);
 302
 303         if (!pathname || !*pathname)
 304                 return ERR_PTR(-EINVAL);
 305
 306         error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 307         if (error)
 308                 return ERR_PTR(error);
 309
 310         inode = path.dentry->d_inode;
 311         mod = inode->i_mode;
 312         ubi_num = ubi_major2num(imajor(inode));
 313         vol_id = iminor(inode) - 1;
 314         path_put(&path);
 315
 316         if (!S_ISCHR(mod))
 317                 return ERR_PTR(-EINVAL);
 318         if (vol_id >= 0 && ubi_num >= 0)
 319                 return ubi_open_volume(ubi_num, vol_id, mode);
 320         return ERR_PTR(-ENODEV);
 321 }
 322 EXPORT_SYMBOL_GPL(ubi_open_volume_path);
 323
 324 /**
 325  * ubi_close_volume - close UBI volume.
 326  * @desc: volume descriptor
 327  */
 328 void ubi_close_volume(struct ubi_volume_desc *desc)
 329 {
 330         struct ubi_volume *vol = desc->vol;
 331         struct ubi_device *ubi = vol->ubi;
 332
 333         dbg_gen("close device %d, volume %d, mode %d",
 334                 ubi->ubi_num, vol->vol_id, desc->mode);
 335
 336         spin_lock(&ubi->volumes_lock);
 337         switch (desc->mode) {
 338         case UBI_READONLY:
 339                 vol->readers -= 1;
 340                 break;
 341         case UBI_READWRITE:
 342                 vol->writers -= 1;
 343                 break;
 344         case UBI_EXCLUSIVE:
 345                 vol->exclusive = 0;
 346         }
 347         vol->ref_count -= 1;
 348         spin_unlock(&ubi->volumes_lock);
 349
 350         kfree(desc);
 351         put_device(&vol->dev);
 352         ubi_put_device(ubi);
 353         module_put(THIS_MODULE);
 354 }
 355 EXPORT_SYMBOL_GPL(ubi_close_volume);
 356
 357 /**
 358  * ubi_leb_read - read data.
 359  * @desc: volume descriptor
 360  * @lnum: logical eraseblock number to read from
 361  * @buf: buffer where to store the read data
 362  * @offset: offset within the logical eraseblock to read from
 363  * @len: how many bytes to read
 364  * @check: whether UBI has to check the read data's CRC or not.
 365  *
 366  * This function reads data from offset @offset of logical eraseblock @lnum and
 367  * stores the data at @buf. When reading from static volumes, @check specifies
 368  * whether the data has to be checked or not. If yes, the whole logical
 369  * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 370  * checksum is per-eraseblock). So checking may substantially slow down the
 371  * read speed. The @check argument is ignored for dynamic volumes.
 372  *
 373  * In case of success, this function returns zero. In case of failure, this
 374  * function returns a negative error code.
 375  *
 376  * %-EBADMSG error code is returned:
 377  * o for both static and dynamic volumes if MTD driver has detected a data
 378  *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 379  * o for static volumes in case of data CRC mismatch.
 380  *
 381  * If the volume is damaged because of an interrupted update this function just
 382  * returns immediately with %-EBADF error code.
 383  */
 384 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 385                  int len, int check)
 386 {
 387         struct ubi_volume *vol = desc->vol;
 388         struct ubi_device *ubi = vol->ubi;
 389         int err, vol_id = vol->vol_id;
 390
 391         dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 392
 393         if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 394             lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 395             offset + len > vol->usable_leb_size)
 396                 return -EINVAL;
 397
 398         if (vol->vol_type == UBI_STATIC_VOLUME) {
 399                 if (vol->used_ebs == 0)
 400                         /* Empty static UBI volume */
 401                         return 0;
 402                 if (lnum == vol->used_ebs - 1 &&
 403                     offset + len > vol->last_eb_bytes)
 404                         return -EINVAL;
 405         }
 406
 407         if (vol->upd_marker)
 408                 return -EBADF;
 409         if (len == 0)
 410                 return 0;
 411
 412         err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
 413         if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 414                 ubi_warn("mark volume %d as corrupted", vol_id);
 415                 vol->corrupted = 1;
 416         }
 417
 418         return err;
 419 }
 420 EXPORT_SYMBOL_GPL(ubi_leb_read);
 421
 422 /**
 423  * ubi_leb_write - write data.
 424  * @desc: volume descriptor
 425  * @lnum: logical eraseblock number to write to
 426  * @buf: data to write
 427  * @offset: offset within the logical eraseblock where to write
 428  * @len: how many bytes to write
 429  * @dtype: expected data type
 430  *
 431  * This function writes @len bytes of data from @buf to offset @offset of
 432  * logical eraseblock @lnum. The @dtype argument describes expected lifetime of
 433  * the data.
 434  *
 435  * This function takes care of physical eraseblock write failures. If write to
 436  * the physical eraseblock write operation fails, the logical eraseblock is
 437  * re-mapped to another physical eraseblock, the data is recovered, and the
 438  * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 439  *
 440  * If all the data were successfully written, zero is returned. If an error
 441  * occurred and UBI has not been able to recover from it, this function returns
 442  * a negative error code. Note, in case of an error, it is possible that
 443  * something was still written to the flash media, but that may be some
 444  * garbage.
 445  *
 446  * If the volume is damaged because of an interrupted update this function just
 447  * returns immediately with %-EBADF code.
 448  */
 449 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 450                   int offset, int len, int dtype)
 451 {
 452         struct ubi_volume *vol = desc->vol;
 453         struct ubi_device *ubi = vol->ubi;
 454         int vol_id = vol->vol_id;
 455
 456         dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 457
 458         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 459                 return -EINVAL;
 460
 461         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 462                 return -EROFS;
 463
 464         if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 465             offset + len > vol->usable_leb_size ||
 466             offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
 467                 return -EINVAL;
 468
 469         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 470             dtype != UBI_UNKNOWN)
 471                 return -EINVAL;
 472
 473         if (vol->upd_marker)
 474                 return -EBADF;
 475
 476         if (len == 0)
 477                 return 0;
 478
 479         return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len, dtype);
 480 }
 481 EXPORT_SYMBOL_GPL(ubi_leb_write);
 482
 483 /*
 484  * ubi_leb_change - change logical eraseblock atomically.
 485  * @desc: volume descriptor
 486  * @lnum: logical eraseblock number to change
 487  * @buf: data to write
 488  * @len: how many bytes to write
 489  * @dtype: expected data type
 490  *
 491  * This function changes the contents of a logical eraseblock atomically. @buf
 492  * has to contain new logical eraseblock data, and @len - the length of the
 493  * data, which has to be aligned. The length may be shorter than the logical
 494  * eraseblock size, ant the logical eraseblock may be appended to more times
 495  * later on. This function guarantees that in case of an unclean reboot the old
 496  * contents is preserved. Returns zero in case of success and a negative error
 497  * code in case of failure.
 498  */
 499 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 500                    int len, int dtype)
 501 {
 502         struct ubi_volume *vol = desc->vol;
 503         struct ubi_device *ubi = vol->ubi;
 504         int vol_id = vol->vol_id;
 505
 506         dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 507
 508         if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 509                 return -EINVAL;
 510
 511         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 512                 return -EROFS;
 513
 514         if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 515             len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
 516                 return -EINVAL;
 517
 518         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 519             dtype != UBI_UNKNOWN)
 520                 return -EINVAL;
 521
 522         if (vol->upd_marker)
 523                 return -EBADF;
 524
 525         if (len == 0)
 526                 return 0;
 527
 528         return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len, dtype);
 529 }
 530 EXPORT_SYMBOL_GPL(ubi_leb_change);
 531
 532 /**
 533  * ubi_leb_erase - erase logical eraseblock.
 534  * @desc: volume descriptor
 535  * @lnum: logical eraseblock number
 536  *
 537  * This function un-maps logical eraseblock @lnum and synchronously erases the
 538  * correspondent physical eraseblock. Returns zero in case of success and a
 539  * negative error code in case of failure.
 540  *
 541  * If the volume is damaged because of an interrupted update this function just
 542  * returns immediately with %-EBADF code.
 543  */
 544 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 545 {
 546         struct ubi_volume *vol = desc->vol;
 547         struct ubi_device *ubi = vol->ubi;
 548         int err;
 549
 550         dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 551
 552         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 553                 return -EROFS;
 554
 555         if (lnum < 0 || lnum >= vol->reserved_pebs)
 556                 return -EINVAL;
 557
 558         if (vol->upd_marker)
 559                 return -EBADF;
 560
 561         err = ubi_eba_unmap_leb(ubi, vol, lnum);
 562         if (err)
 563                 return err;
 564
 565         return ubi_wl_flush(ubi);
 566 }
 567 EXPORT_SYMBOL_GPL(ubi_leb_erase);
 568
 569 /**
 570  * ubi_leb_unmap - un-map logical eraseblock.
 571  * @desc: volume descriptor
 572  * @lnum: logical eraseblock number
 573  *
 574  * This function un-maps logical eraseblock @lnum and schedules the
 575  * corresponding physical eraseblock for erasure, so that it will eventually be
 576  * physically erased in background. This operation is much faster than the
 577  * erase operation.
 578  *
 579  * Unlike erase, the un-map operation does not guarantee that the logical
 580  * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 581  * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 582  * happens after this, the logical eraseblocks will not necessarily be
 583  * un-mapped again when this MTD device is attached. They may actually be
 584  * mapped to the same physical eraseblocks again. So, this function has to be
 585  * used with care.
 586  *
 587  * In other words, when un-mapping a logical eraseblock, UBI does not store
 588  * any information about this on the flash media, it just marks the logical
 589  * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 590  * eraseblock is physically erased, it will be mapped again to the same logical
 591  * eraseblock when the MTD device is attached again.
 592  *
 593  * The main and obvious use-case of this function is when the contents of a
 594  * logical eraseblock has to be re-written. Then it is much more efficient to
 595  * first un-map it, then write new data, rather than first erase it, then write
 596  * new data. Note, once new data has been written to the logical eraseblock,
 597  * UBI guarantees that the old contents has gone forever. In other words, if an
 598  * unclean reboot happens after the logical eraseblock has been un-mapped and
 599  * then written to, it will contain the last written data.
 600  *
 601  * This function returns zero in case of success and a negative error code in
 602  * case of failure. If the volume is damaged because of an interrupted update
 603  * this function just returns immediately with %-EBADF code.
 604  */
 605 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 606 {
 607         struct ubi_volume *vol = desc->vol;
 608         struct ubi_device *ubi = vol->ubi;
 609
 610         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 611
 612         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 613                 return -EROFS;
 614
 615         if (lnum < 0 || lnum >= vol->reserved_pebs)
 616                 return -EINVAL;
 617
 618         if (vol->upd_marker)
 619                 return -EBADF;
 620
 621         return ubi_eba_unmap_leb(ubi, vol, lnum);
 622 }
 623 EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 624
 625 /**
 626  * ubi_leb_map - map logical eraseblock to a physical eraseblock.
 627  * @desc: volume descriptor
 628  * @lnum: logical eraseblock number
 629  * @dtype: expected data type
 630  *
 631  * This function maps an un-mapped logical eraseblock @lnum to a physical
 632  * eraseblock. This means, that after a successful invocation of this
 633  * function the logical eraseblock @lnum will be empty (contain only %0xFF
 634  * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
 635  * happens.
 636  *
 637  * This function returns zero in case of success, %-EBADF if the volume is
 638  * damaged because of an interrupted update, %-EBADMSG if the logical
 639  * eraseblock is already mapped, and other negative error codes in case of
 640  * other failures.
 641  */
 642 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype)
 643 {
 644         struct ubi_volume *vol = desc->vol;
 645         struct ubi_device *ubi = vol->ubi;
 646
 647         dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 648
 649         if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 650                 return -EROFS;
 651
 652         if (lnum < 0 || lnum >= vol->reserved_pebs)
 653                 return -EINVAL;
 654
 655         if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM &&
 656             dtype != UBI_UNKNOWN)
 657                 return -EINVAL;
 658
 659         if (vol->upd_marker)
 660                 return -EBADF;
 661
 662         if (vol->eba_tbl[lnum] >= 0)
 663                 return -EBADMSG;
 664
 665         return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0, dtype);
 666 }
 667 EXPORT_SYMBOL_GPL(ubi_leb_map);
 668
 669 /**
 670  * ubi_is_mapped - check if logical eraseblock is mapped.
 671  * @desc: volume descriptor
 672  * @lnum: logical eraseblock number
 673  *
 674  * This function checks if logical eraseblock @lnum is mapped to a physical
 675  * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 676  * mean it will still be un-mapped after the UBI device is re-attached. The
 677  * logical eraseblock may become mapped to the physical eraseblock it was last
 678  * mapped to.
 679  *
 680  * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 681  * error code in case of failure. If the volume is damaged because of an
 682  * interrupted update this function just returns immediately with %-EBADF error
 683  * code.
 684  */
 685 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 686 {
 687         struct ubi_volume *vol = desc->vol;
 688
 689         dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
 690
 691         if (lnum < 0 || lnum >= vol->reserved_pebs)
 692                 return -EINVAL;
 693
 694         if (vol->upd_marker)
 695                 return -EBADF;
 696
 697         return vol->eba_tbl[lnum] >= 0;
 698 }
 699 EXPORT_SYMBOL_GPL(ubi_is_mapped);
 700
 701 /**
 702  * ubi_sync - synchronize UBI device buffers.
 703  * @ubi_num: UBI device to synchronize
 704  *
 705  * The underlying MTD device may cache data in hardware or in software. This
 706  * function ensures the caches are flushed. Returns zero in case of success and
 707  * a negative error code in case of failure.
 708  */
 709 int ubi_sync(int ubi_num)
 710 {
 711         struct ubi_device *ubi;
 712
 713         ubi = ubi_get_device(ubi_num);
 714         if (!ubi)
 715                 return -ENODEV;
 716
 717         mtd_sync(ubi->mtd);
 718         ubi_put_device(ubi);
 719         return 0;
 720 }
 721 EXPORT_SYMBOL_GPL(ubi_sync);
 722
 723 BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
 724
 725 /**
 726  * ubi_register_volume_notifier - register a volume notifier.
 727  * @nb: the notifier description object
 728  * @ignore_existing: if non-zero, do not send "added" notification for all
 729  *                   already existing volumes
 730  *
 731  * This function registers a volume notifier, which means that
 732  * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
 733  * removed, re-sized, re-named, or updated. The first argument of the function
 734  * is the notification type. The second argument is pointer to a
 735  * &struct ubi_notification object which describes the notification event.
 736  * Using UBI API from the volume notifier is prohibited.
 737  *
 738  * This function returns zero in case of success and a negative error code
 739  * in case of failure.
 740  */
 741 int ubi_register_volume_notifier(struct notifier_block *nb,
 742                                  int ignore_existing)
 743 {
 744         int err;
 745
 746         err = blocking_notifier_chain_register(&ubi_notifiers, nb);
 747         if (err != 0)
 748                 return err;
 749         if (ignore_existing)
 750                 return 0;
 751
 752         /*
 753          * We are going to walk all UBI devices and all volumes, and
 754          * notify the user about existing volumes by the %UBI_VOLUME_ADDED
 755          * event. We have to lock the @ubi_devices_mutex to make sure UBI
 756          * devices do not disappear.
 757          */
 758         mutex_lock(&ubi_devices_mutex);
 759         ubi_enumerate_volumes(nb);
 760         mutex_unlock(&ubi_devices_mutex);
 761
 762         return err;
 763 }
 764 EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
 765
 766 /**
 767  * ubi_unregister_volume_notifier - unregister the volume notifier.
 768  * @nb: the notifier description object
 769  *
 770  * This function unregisters volume notifier @nm and returns zero in case of
 771  * success and a negative error code in case of failure.
 772  */
 773 int ubi_unregister_volume_notifier(struct notifier_block *nb)
 774 {
 775         return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
 776 }
 777 EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);