linux/drivers/mtd/ubi/kapi.c
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   1/*
   2 * Copyright (c) International Business Machines Corp., 2006
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  12 * the GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17 *
  18 * Author: Artem Bityutskiy (Битюцкий Артём)
  19 */
  20
  21/* 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 */
  39void 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}
  49EXPORT_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 */
  59int 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}
  72EXPORT_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 */
  80void 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 */
 102void 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}
 107EXPORT_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 */
 127struct 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 && mode != UBI_METAONLY)
 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                    vol->metaonly)
 187                        goto out_unlock;
 188                vol->exclusive = 1;
 189                break;
 190
 191        case UBI_METAONLY:
 192                if (vol->metaonly || vol->exclusive)
 193                        goto out_unlock;
 194                vol->metaonly = 1;
 195                break;
 196        }
 197        get_device(&vol->dev);
 198        vol->ref_count += 1;
 199        spin_unlock(&ubi->volumes_lock);
 200
 201        desc->vol = vol;
 202        desc->mode = mode;
 203
 204        mutex_lock(&ubi->ckvol_mutex);
 205        if (!vol->checked) {
 206                /* This is the first open - check the volume */
 207                err = ubi_check_volume(ubi, vol_id);
 208                if (err < 0) {
 209                        mutex_unlock(&ubi->ckvol_mutex);
 210                        ubi_close_volume(desc);
 211                        return ERR_PTR(err);
 212                }
 213                if (err == 1) {
 214                        ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
 215                                 vol_id, ubi->ubi_num);
 216                        vol->corrupted = 1;
 217                }
 218                vol->checked = 1;
 219        }
 220        mutex_unlock(&ubi->ckvol_mutex);
 221
 222        return desc;
 223
 224out_unlock:
 225        spin_unlock(&ubi->volumes_lock);
 226        module_put(THIS_MODULE);
 227out_free:
 228        kfree(desc);
 229out_put_ubi:
 230        ubi_put_device(ubi);
 231        ubi_err(ubi, "cannot open device %d, volume %d, error %d",
 232                ubi_num, vol_id, err);
 233        return ERR_PTR(err);
 234}
 235EXPORT_SYMBOL_GPL(ubi_open_volume);
 236
 237/**
 238 * ubi_open_volume_nm - open UBI volume by name.
 239 * @ubi_num: UBI device number
 240 * @name: volume name
 241 * @mode: open mode
 242 *
 243 * This function is similar to 'ubi_open_volume()', but opens a volume by name.
 244 */
 245struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 246                                           int mode)
 247{
 248        int i, vol_id = -1, len;
 249        struct ubi_device *ubi;
 250        struct ubi_volume_desc *ret;
 251
 252        dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
 253
 254        if (!name)
 255                return ERR_PTR(-EINVAL);
 256
 257        len = strnlen(name, UBI_VOL_NAME_MAX + 1);
 258        if (len > UBI_VOL_NAME_MAX)
 259                return ERR_PTR(-EINVAL);
 260
 261        if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
 262                return ERR_PTR(-EINVAL);
 263
 264        ubi = ubi_get_device(ubi_num);
 265        if (!ubi)
 266                return ERR_PTR(-ENODEV);
 267
 268        spin_lock(&ubi->volumes_lock);
 269        /* Walk all volumes of this UBI device */
 270        for (i = 0; i < ubi->vtbl_slots; i++) {
 271                struct ubi_volume *vol = ubi->volumes[i];
 272
 273                if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
 274                        vol_id = i;
 275                        break;
 276                }
 277        }
 278        spin_unlock(&ubi->volumes_lock);
 279
 280        if (vol_id >= 0)
 281                ret = ubi_open_volume(ubi_num, vol_id, mode);
 282        else
 283                ret = ERR_PTR(-ENODEV);
 284
 285        /*
 286         * We should put the UBI device even in case of success, because
 287         * 'ubi_open_volume()' took a reference as well.
 288         */
 289        ubi_put_device(ubi);
 290        return ret;
 291}
 292EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
 293
 294/**
 295 * ubi_open_volume_path - open UBI volume by its character device node path.
 296 * @pathname: volume character device node path
 297 * @mode: open mode
 298 *
 299 * This function is similar to 'ubi_open_volume()', but opens a volume the path
 300 * to its character device node.
 301 */
 302struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
 303{
 304        int error, ubi_num, vol_id;
 305        struct path path;
 306        struct kstat stat;
 307
 308        dbg_gen("open volume %s, mode %d", pathname, mode);
 309
 310        if (!pathname || !*pathname)
 311                return ERR_PTR(-EINVAL);
 312
 313        error = kern_path(pathname, LOOKUP_FOLLOW, &path);
 314        if (error)
 315                return ERR_PTR(error);
 316
 317        error = vfs_getattr(&path, &stat);
 318        path_put(&path);
 319        if (error)
 320                return ERR_PTR(error);
 321
 322        if (!S_ISCHR(stat.mode))
 323                return ERR_PTR(-EINVAL);
 324
 325        ubi_num = ubi_major2num(MAJOR(stat.rdev));
 326        vol_id = MINOR(stat.rdev) - 1;
 327
 328        if (vol_id >= 0 && ubi_num >= 0)
 329                return ubi_open_volume(ubi_num, vol_id, mode);
 330        return ERR_PTR(-ENODEV);
 331}
 332EXPORT_SYMBOL_GPL(ubi_open_volume_path);
 333
 334/**
 335 * ubi_close_volume - close UBI volume.
 336 * @desc: volume descriptor
 337 */
 338void ubi_close_volume(struct ubi_volume_desc *desc)
 339{
 340        struct ubi_volume *vol = desc->vol;
 341        struct ubi_device *ubi = vol->ubi;
 342
 343        dbg_gen("close device %d, volume %d, mode %d",
 344                ubi->ubi_num, vol->vol_id, desc->mode);
 345
 346        spin_lock(&ubi->volumes_lock);
 347        switch (desc->mode) {
 348        case UBI_READONLY:
 349                vol->readers -= 1;
 350                break;
 351        case UBI_READWRITE:
 352                vol->writers -= 1;
 353                break;
 354        case UBI_EXCLUSIVE:
 355                vol->exclusive = 0;
 356                break;
 357        case UBI_METAONLY:
 358                vol->metaonly = 0;
 359                break;
 360        }
 361        vol->ref_count -= 1;
 362        spin_unlock(&ubi->volumes_lock);
 363
 364        kfree(desc);
 365        put_device(&vol->dev);
 366        ubi_put_device(ubi);
 367        module_put(THIS_MODULE);
 368}
 369EXPORT_SYMBOL_GPL(ubi_close_volume);
 370
 371/**
 372 * leb_read_sanity_check - does sanity checks on read requests.
 373 * @desc: volume descriptor
 374 * @lnum: logical eraseblock number to read from
 375 * @offset: offset within the logical eraseblock to read from
 376 * @len: how many bytes to read
 377 *
 378 * This function is used by ubi_leb_read() and ubi_leb_read_sg()
 379 * to perform sanity checks.
 380 */
 381static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
 382                                 int offset, int len)
 383{
 384        struct ubi_volume *vol = desc->vol;
 385        struct ubi_device *ubi = vol->ubi;
 386        int vol_id = vol->vol_id;
 387
 388        if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
 389            lnum >= vol->used_ebs || offset < 0 || len < 0 ||
 390            offset + len > vol->usable_leb_size)
 391                return -EINVAL;
 392
 393        if (vol->vol_type == UBI_STATIC_VOLUME) {
 394                if (vol->used_ebs == 0)
 395                        /* Empty static UBI volume */
 396                        return 0;
 397                if (lnum == vol->used_ebs - 1 &&
 398                    offset + len > vol->last_eb_bytes)
 399                        return -EINVAL;
 400        }
 401
 402        if (vol->upd_marker)
 403                return -EBADF;
 404
 405        return 0;
 406}
 407
 408/**
 409 * ubi_leb_read - read data.
 410 * @desc: volume descriptor
 411 * @lnum: logical eraseblock number to read from
 412 * @buf: buffer where to store the read data
 413 * @offset: offset within the logical eraseblock to read from
 414 * @len: how many bytes to read
 415 * @check: whether UBI has to check the read data's CRC or not.
 416 *
 417 * This function reads data from offset @offset of logical eraseblock @lnum and
 418 * stores the data at @buf. When reading from static volumes, @check specifies
 419 * whether the data has to be checked or not. If yes, the whole logical
 420 * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
 421 * checksum is per-eraseblock). So checking may substantially slow down the
 422 * read speed. The @check argument is ignored for dynamic volumes.
 423 *
 424 * In case of success, this function returns zero. In case of failure, this
 425 * function returns a negative error code.
 426 *
 427 * %-EBADMSG error code is returned:
 428 * o for both static and dynamic volumes if MTD driver has detected a data
 429 *   integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
 430 * o for static volumes in case of data CRC mismatch.
 431 *
 432 * If the volume is damaged because of an interrupted update this function just
 433 * returns immediately with %-EBADF error code.
 434 */
 435int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 436                 int len, int check)
 437{
 438        struct ubi_volume *vol = desc->vol;
 439        struct ubi_device *ubi = vol->ubi;
 440        int err, vol_id = vol->vol_id;
 441
 442        dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 443
 444        err = leb_read_sanity_check(desc, lnum, offset, len);
 445        if (err < 0)
 446                return err;
 447
 448        if (len == 0)
 449                return 0;
 450
 451        err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
 452        if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 453                ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
 454                vol->corrupted = 1;
 455        }
 456
 457        return err;
 458}
 459EXPORT_SYMBOL_GPL(ubi_leb_read);
 460
 461
 462/**
 463 * ubi_leb_read_sg - read data into a scatter gather list.
 464 * @desc: volume descriptor
 465 * @lnum: logical eraseblock number to read from
 466 * @buf: buffer where to store the read data
 467 * @offset: offset within the logical eraseblock to read from
 468 * @len: how many bytes to read
 469 * @check: whether UBI has to check the read data's CRC or not.
 470 *
 471 * This function works exactly like ubi_leb_read_sg(). But instead of
 472 * storing the read data into a buffer it writes to an UBI scatter gather
 473 * list.
 474 */
 475int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
 476                    int offset, int len, int check)
 477{
 478        struct ubi_volume *vol = desc->vol;
 479        struct ubi_device *ubi = vol->ubi;
 480        int err, vol_id = vol->vol_id;
 481
 482        dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
 483
 484        err = leb_read_sanity_check(desc, lnum, offset, len);
 485        if (err < 0)
 486                return err;
 487
 488        if (len == 0)
 489                return 0;
 490
 491        err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
 492        if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
 493                ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
 494                vol->corrupted = 1;
 495        }
 496
 497        return err;
 498}
 499EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
 500
 501/**
 502 * ubi_leb_write - write data.
 503 * @desc: volume descriptor
 504 * @lnum: logical eraseblock number to write to
 505 * @buf: data to write
 506 * @offset: offset within the logical eraseblock where to write
 507 * @len: how many bytes to write
 508 *
 509 * This function writes @len bytes of data from @buf to offset @offset of
 510 * logical eraseblock @lnum.
 511 *
 512 * This function takes care of physical eraseblock write failures. If write to
 513 * the physical eraseblock write operation fails, the logical eraseblock is
 514 * re-mapped to another physical eraseblock, the data is recovered, and the
 515 * write finishes. UBI has a pool of reserved physical eraseblocks for this.
 516 *
 517 * If all the data were successfully written, zero is returned. If an error
 518 * occurred and UBI has not been able to recover from it, this function returns
 519 * a negative error code. Note, in case of an error, it is possible that
 520 * something was still written to the flash media, but that may be some
 521 * garbage.
 522 *
 523 * If the volume is damaged because of an interrupted update this function just
 524 * returns immediately with %-EBADF code.
 525 */
 526int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 527                  int offset, int len)
 528{
 529        struct ubi_volume *vol = desc->vol;
 530        struct ubi_device *ubi = vol->ubi;
 531        int vol_id = vol->vol_id;
 532
 533        dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
 534
 535        if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 536                return -EINVAL;
 537
 538        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 539                return -EROFS;
 540
 541        if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
 542            offset + len > vol->usable_leb_size ||
 543            offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
 544                return -EINVAL;
 545
 546        if (vol->upd_marker)
 547                return -EBADF;
 548
 549        if (len == 0)
 550                return 0;
 551
 552        return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
 553}
 554EXPORT_SYMBOL_GPL(ubi_leb_write);
 555
 556/*
 557 * ubi_leb_change - change logical eraseblock atomically.
 558 * @desc: volume descriptor
 559 * @lnum: logical eraseblock number to change
 560 * @buf: data to write
 561 * @len: how many bytes to write
 562 *
 563 * This function changes the contents of a logical eraseblock atomically. @buf
 564 * has to contain new logical eraseblock data, and @len - the length of the
 565 * data, which has to be aligned. The length may be shorter than the logical
 566 * eraseblock size, ant the logical eraseblock may be appended to more times
 567 * later on. This function guarantees that in case of an unclean reboot the old
 568 * contents is preserved. Returns zero in case of success and a negative error
 569 * code in case of failure.
 570 */
 571int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 572                   int len)
 573{
 574        struct ubi_volume *vol = desc->vol;
 575        struct ubi_device *ubi = vol->ubi;
 576        int vol_id = vol->vol_id;
 577
 578        dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
 579
 580        if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
 581                return -EINVAL;
 582
 583        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 584                return -EROFS;
 585
 586        if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
 587            len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
 588                return -EINVAL;
 589
 590        if (vol->upd_marker)
 591                return -EBADF;
 592
 593        if (len == 0)
 594                return 0;
 595
 596        return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
 597}
 598EXPORT_SYMBOL_GPL(ubi_leb_change);
 599
 600/**
 601 * ubi_leb_erase - erase logical eraseblock.
 602 * @desc: volume descriptor
 603 * @lnum: logical eraseblock number
 604 *
 605 * This function un-maps logical eraseblock @lnum and synchronously erases the
 606 * correspondent physical eraseblock. Returns zero in case of success and a
 607 * negative error code in case of failure.
 608 *
 609 * If the volume is damaged because of an interrupted update this function just
 610 * returns immediately with %-EBADF code.
 611 */
 612int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
 613{
 614        struct ubi_volume *vol = desc->vol;
 615        struct ubi_device *ubi = vol->ubi;
 616        int err;
 617
 618        dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
 619
 620        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 621                return -EROFS;
 622
 623        if (lnum < 0 || lnum >= vol->reserved_pebs)
 624                return -EINVAL;
 625
 626        if (vol->upd_marker)
 627                return -EBADF;
 628
 629        err = ubi_eba_unmap_leb(ubi, vol, lnum);
 630        if (err)
 631                return err;
 632
 633        return ubi_wl_flush(ubi, vol->vol_id, lnum);
 634}
 635EXPORT_SYMBOL_GPL(ubi_leb_erase);
 636
 637/**
 638 * ubi_leb_unmap - un-map logical eraseblock.
 639 * @desc: volume descriptor
 640 * @lnum: logical eraseblock number
 641 *
 642 * This function un-maps logical eraseblock @lnum and schedules the
 643 * corresponding physical eraseblock for erasure, so that it will eventually be
 644 * physically erased in background. This operation is much faster than the
 645 * erase operation.
 646 *
 647 * Unlike erase, the un-map operation does not guarantee that the logical
 648 * eraseblock will contain all 0xFF bytes when UBI is initialized again. For
 649 * example, if several logical eraseblocks are un-mapped, and an unclean reboot
 650 * happens after this, the logical eraseblocks will not necessarily be
 651 * un-mapped again when this MTD device is attached. They may actually be
 652 * mapped to the same physical eraseblocks again. So, this function has to be
 653 * used with care.
 654 *
 655 * In other words, when un-mapping a logical eraseblock, UBI does not store
 656 * any information about this on the flash media, it just marks the logical
 657 * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
 658 * eraseblock is physically erased, it will be mapped again to the same logical
 659 * eraseblock when the MTD device is attached again.
 660 *
 661 * The main and obvious use-case of this function is when the contents of a
 662 * logical eraseblock has to be re-written. Then it is much more efficient to
 663 * first un-map it, then write new data, rather than first erase it, then write
 664 * new data. Note, once new data has been written to the logical eraseblock,
 665 * UBI guarantees that the old contents has gone forever. In other words, if an
 666 * unclean reboot happens after the logical eraseblock has been un-mapped and
 667 * then written to, it will contain the last written data.
 668 *
 669 * This function returns zero in case of success and a negative error code in
 670 * case of failure. If the volume is damaged because of an interrupted update
 671 * this function just returns immediately with %-EBADF code.
 672 */
 673int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
 674{
 675        struct ubi_volume *vol = desc->vol;
 676        struct ubi_device *ubi = vol->ubi;
 677
 678        dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
 679
 680        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 681                return -EROFS;
 682
 683        if (lnum < 0 || lnum >= vol->reserved_pebs)
 684                return -EINVAL;
 685
 686        if (vol->upd_marker)
 687                return -EBADF;
 688
 689        return ubi_eba_unmap_leb(ubi, vol, lnum);
 690}
 691EXPORT_SYMBOL_GPL(ubi_leb_unmap);
 692
 693/**
 694 * ubi_leb_map - map logical eraseblock to a physical eraseblock.
 695 * @desc: volume descriptor
 696 * @lnum: logical eraseblock number
 697 *
 698 * This function maps an un-mapped logical eraseblock @lnum to a physical
 699 * eraseblock. This means, that after a successful invocation of this
 700 * function the logical eraseblock @lnum will be empty (contain only %0xFF
 701 * bytes) and be mapped to a physical eraseblock, even if an unclean reboot
 702 * happens.
 703 *
 704 * This function returns zero in case of success, %-EBADF if the volume is
 705 * damaged because of an interrupted update, %-EBADMSG if the logical
 706 * eraseblock is already mapped, and other negative error codes in case of
 707 * other failures.
 708 */
 709int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
 710{
 711        struct ubi_volume *vol = desc->vol;
 712        struct ubi_device *ubi = vol->ubi;
 713
 714        dbg_gen("map LEB %d:%d", vol->vol_id, lnum);
 715
 716        if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
 717                return -EROFS;
 718
 719        if (lnum < 0 || lnum >= vol->reserved_pebs)
 720                return -EINVAL;
 721
 722        if (vol->upd_marker)
 723                return -EBADF;
 724
 725        if (vol->eba_tbl[lnum] >= 0)
 726                return -EBADMSG;
 727
 728        return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
 729}
 730EXPORT_SYMBOL_GPL(ubi_leb_map);
 731
 732/**
 733 * ubi_is_mapped - check if logical eraseblock is mapped.
 734 * @desc: volume descriptor
 735 * @lnum: logical eraseblock number
 736 *
 737 * This function checks if logical eraseblock @lnum is mapped to a physical
 738 * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
 739 * mean it will still be un-mapped after the UBI device is re-attached. The
 740 * logical eraseblock may become mapped to the physical eraseblock it was last
 741 * mapped to.
 742 *
 743 * This function returns %1 if the LEB is mapped, %0 if not, and a negative
 744 * error code in case of failure. If the volume is damaged because of an
 745 * interrupted update this function just returns immediately with %-EBADF error
 746 * code.
 747 */
 748int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
 749{
 750        struct ubi_volume *vol = desc->vol;
 751
 752        dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
 753
 754        if (lnum < 0 || lnum >= vol->reserved_pebs)
 755                return -EINVAL;
 756
 757        if (vol->upd_marker)
 758                return -EBADF;
 759
 760        return vol->eba_tbl[lnum] >= 0;
 761}
 762EXPORT_SYMBOL_GPL(ubi_is_mapped);
 763
 764/**
 765 * ubi_sync - synchronize UBI device buffers.
 766 * @ubi_num: UBI device to synchronize
 767 *
 768 * The underlying MTD device may cache data in hardware or in software. This
 769 * function ensures the caches are flushed. Returns zero in case of success and
 770 * a negative error code in case of failure.
 771 */
 772int ubi_sync(int ubi_num)
 773{
 774        struct ubi_device *ubi;
 775
 776        ubi = ubi_get_device(ubi_num);
 777        if (!ubi)
 778                return -ENODEV;
 779
 780        mtd_sync(ubi->mtd);
 781        ubi_put_device(ubi);
 782        return 0;
 783}
 784EXPORT_SYMBOL_GPL(ubi_sync);
 785
 786/**
 787 * ubi_flush - flush UBI work queue.
 788 * @ubi_num: UBI device to flush work queue
 789 * @vol_id: volume id to flush for
 790 * @lnum: logical eraseblock number to flush for
 791 *
 792 * This function executes all pending works for a particular volume id / logical
 793 * eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
 794 * a wildcard for all of the corresponding volume numbers or logical
 795 * eraseblock numbers. It returns zero in case of success and a negative error
 796 * code in case of failure.
 797 */
 798int ubi_flush(int ubi_num, int vol_id, int lnum)
 799{
 800        struct ubi_device *ubi;
 801        int err = 0;
 802
 803        ubi = ubi_get_device(ubi_num);
 804        if (!ubi)
 805                return -ENODEV;
 806
 807        err = ubi_wl_flush(ubi, vol_id, lnum);
 808        ubi_put_device(ubi);
 809        return err;
 810}
 811EXPORT_SYMBOL_GPL(ubi_flush);
 812
 813BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
 814
 815/**
 816 * ubi_register_volume_notifier - register a volume notifier.
 817 * @nb: the notifier description object
 818 * @ignore_existing: if non-zero, do not send "added" notification for all
 819 *                   already existing volumes
 820 *
 821 * This function registers a volume notifier, which means that
 822 * 'nb->notifier_call()' will be invoked when an UBI  volume is created,
 823 * removed, re-sized, re-named, or updated. The first argument of the function
 824 * is the notification type. The second argument is pointer to a
 825 * &struct ubi_notification object which describes the notification event.
 826 * Using UBI API from the volume notifier is prohibited.
 827 *
 828 * This function returns zero in case of success and a negative error code
 829 * in case of failure.
 830 */
 831int ubi_register_volume_notifier(struct notifier_block *nb,
 832                                 int ignore_existing)
 833{
 834        int err;
 835
 836        err = blocking_notifier_chain_register(&ubi_notifiers, nb);
 837        if (err != 0)
 838                return err;
 839        if (ignore_existing)
 840                return 0;
 841
 842        /*
 843         * We are going to walk all UBI devices and all volumes, and
 844         * notify the user about existing volumes by the %UBI_VOLUME_ADDED
 845         * event. We have to lock the @ubi_devices_mutex to make sure UBI
 846         * devices do not disappear.
 847         */
 848        mutex_lock(&ubi_devices_mutex);
 849        ubi_enumerate_volumes(nb);
 850        mutex_unlock(&ubi_devices_mutex);
 851
 852        return err;
 853}
 854EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
 855
 856/**
 857 * ubi_unregister_volume_notifier - unregister the volume notifier.
 858 * @nb: the notifier description object
 859 *
 860 * This function unregisters volume notifier @nm and returns zero in case of
 861 * success and a negative error code in case of failure.
 862 */
 863int ubi_unregister_volume_notifier(struct notifier_block *nb)
 864{
 865        return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
 866}
 867EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
 868