kapi.c

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/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 */

/* This file mostly implements UBI kernel API functions */

#include <linux/module.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/fs.h>
#include <asm/div64.h>
#include "ubi.h"

void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
{
    di->ubi_num = ubi->ubi_num;
    di->leb_size = ubi->leb_size;
    di->leb_start = ubi->leb_start;
    di->min_io_size = ubi->min_io_size;
    di->max_write_size = ubi->max_write_size;
    di->ro_mode = ubi->ro_mode;
    di->cdev = ubi->cdev.dev;
}
EXPORT_SYMBOL_GPL(ubi_do_get_device_info);

int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
{
    struct ubi_device *ubi;

    if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
        return -EINVAL;
    ubi = ubi_get_device(ubi_num);
    if (!ubi)
        return -ENODEV;
    ubi_do_get_device_info(ubi, di);
    ubi_put_device(ubi);
    return 0;
}
EXPORT_SYMBOL_GPL(ubi_get_device_info);

void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
                struct ubi_volume_info *vi)
{
    vi->vol_id = vol->vol_id;
    vi->ubi_num = ubi->ubi_num;
    vi->size = vol->reserved_pebs;
    vi->used_bytes = vol->used_bytes;
    vi->vol_type = vol->vol_type;
    vi->corrupted = vol->corrupted;
    vi->upd_marker = vol->upd_marker;
    vi->alignment = vol->alignment;
    vi->usable_leb_size = vol->usable_leb_size;
    vi->name_len = vol->name_len;
    vi->name = vol->name;
    vi->cdev = vol->cdev.dev;
}

void ubi_get_volume_info(struct ubi_volume_desc *desc,
             struct ubi_volume_info *vi)
{
    ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
}
EXPORT_SYMBOL_GPL(ubi_get_volume_info);

struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
{
    int err;
    struct ubi_volume_desc *desc;
    struct ubi_device *ubi;
    struct ubi_volume *vol;

    dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);

    if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
        return ERR_PTR(-EINVAL);

    if (mode != UBI_READONLY && mode != UBI_READWRITE &&
        mode != UBI_EXCLUSIVE)
        return ERR_PTR(-EINVAL);

    /*
     * First of all, we have to get the UBI device to prevent its removal.
     */
    ubi = ubi_get_device(ubi_num);
    if (!ubi)
        return ERR_PTR(-ENODEV);

    if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
        err = -EINVAL;
        goto out_put_ubi;
    }

    desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
    if (!desc) {
        err = -ENOMEM;
        goto out_put_ubi;
    }

    err = -ENODEV;
    if (!try_module_get(THIS_MODULE))
        goto out_free;

    spin_lock(&ubi->volumes_lock);
    vol = ubi->volumes[vol_id];
    if (!vol)
        goto out_unlock;

    err = -EBUSY;
    switch (mode) {
    case UBI_READONLY:
        if (vol->exclusive)
            goto out_unlock;
        vol->readers += 1;
        break;

    case UBI_READWRITE:
        if (vol->exclusive || vol->writers > 0)
            goto out_unlock;
        vol->writers += 1;
        break;

    case UBI_EXCLUSIVE:
        if (vol->exclusive || vol->writers || vol->readers)
            goto out_unlock;
        vol->exclusive = 1;
        break;
    }
    get_device(&vol->dev);
    vol->ref_count += 1;
    spin_unlock(&ubi->volumes_lock);

    desc->vol = vol;
    desc->mode = mode;

    mutex_lock(&ubi->ckvol_mutex);
    if (!vol->checked) {
        /* This is the first open - check the volume */
        err = ubi_check_volume(ubi, vol_id);
        if (err < 0) {
            mutex_unlock(&ubi->ckvol_mutex);
            ubi_close_volume(desc);
            return ERR_PTR(err);
        }
        if (err == 1) {
            ubi_warn("volume %d on UBI device %d is corrupted",
                 vol_id, ubi->ubi_num);
            vol->corrupted = 1;
        }
        vol->checked = 1;
    }
    mutex_unlock(&ubi->ckvol_mutex);

    return desc;

out_unlock:
    spin_unlock(&ubi->volumes_lock);
    module_put(THIS_MODULE);
out_free:
    kfree(desc);
out_put_ubi:
    ubi_put_device(ubi);
    ubi_err("cannot open device %d, volume %d, error %d",
        ubi_num, vol_id, err);
    return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(ubi_open_volume);

struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
                       int mode)
{
    int i, vol_id = -1, len;
    struct ubi_device *ubi;
    struct ubi_volume_desc *ret;

    dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);

    if (!name)
        return ERR_PTR(-EINVAL);

    len = strnlen(name, UBI_VOL_NAME_MAX + 1);
    if (len > UBI_VOL_NAME_MAX)
        return ERR_PTR(-EINVAL);

    if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
        return ERR_PTR(-EINVAL);

    ubi = ubi_get_device(ubi_num);
    if (!ubi)
        return ERR_PTR(-ENODEV);

    spin_lock(&ubi->volumes_lock);
    /* Walk all volumes of this UBI device */
    for (i = 0; i < ubi->vtbl_slots; i++) {
        struct ubi_volume *vol = ubi->volumes[i];

        if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
            vol_id = i;
            break;
        }
    }
    spin_unlock(&ubi->volumes_lock);

    if (vol_id >= 0)
        ret = ubi_open_volume(ubi_num, vol_id, mode);
    else
        ret = ERR_PTR(-ENODEV);

    /*
     * We should put the UBI device even in case of success, because
     * 'ubi_open_volume()' took a reference as well.
     */
    ubi_put_device(ubi);
    return ret;
}
EXPORT_SYMBOL_GPL(ubi_open_volume_nm);

struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
{
    int error, ubi_num, vol_id, mod;
    struct inode *inode;
    struct path path;

    dbg_gen("open volume %s, mode %d", pathname, mode);

    if (!pathname || !*pathname)
        return ERR_PTR(-EINVAL);

    error = kern_path(pathname, LOOKUP_FOLLOW, &path);
    if (error)
        return ERR_PTR(error);

    inode = path.dentry->d_inode;
    mod = inode->i_mode;
    ubi_num = ubi_major2num(imajor(inode));
    vol_id = iminor(inode) - 1;
    path_put(&path);

    if (!S_ISCHR(mod))
        return ERR_PTR(-EINVAL);
    if (vol_id >= 0 && ubi_num >= 0)
        return ubi_open_volume(ubi_num, vol_id, mode);
    return ERR_PTR(-ENODEV);
}
EXPORT_SYMBOL_GPL(ubi_open_volume_path);

void ubi_close_volume(struct ubi_volume_desc *desc)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;

    dbg_gen("close device %d, volume %d, mode %d",
        ubi->ubi_num, vol->vol_id, desc->mode);

    spin_lock(&ubi->volumes_lock);
    switch (desc->mode) {
    case UBI_READONLY:
        vol->readers -= 1;
        break;
    case UBI_READWRITE:
        vol->writers -= 1;
        break;
    case UBI_EXCLUSIVE:
        vol->exclusive = 0;
    }
    vol->ref_count -= 1;
    spin_unlock(&ubi->volumes_lock);

    kfree(desc);
    put_device(&vol->dev);
    ubi_put_device(ubi);
    module_put(THIS_MODULE);
}
EXPORT_SYMBOL_GPL(ubi_close_volume);

int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
         int len, int check)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;
    int err, vol_id = vol->vol_id;

    dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);

    if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
        lnum >= vol->used_ebs || offset < 0 || len < 0 ||
        offset + len > vol->usable_leb_size)
        return -EINVAL;

    if (vol->vol_type == UBI_STATIC_VOLUME) {
        if (vol->used_ebs == 0)
            /* Empty static UBI volume */
            return 0;
        if (lnum == vol->used_ebs - 1 &&
            offset + len > vol->last_eb_bytes)
            return -EINVAL;
    }

    if (vol->upd_marker)
        return -EBADF;
    if (len == 0)
        return 0;

    err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
    if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
        ubi_warn("mark volume %d as corrupted", vol_id);
        vol->corrupted = 1;
    }

    return err;
}
EXPORT_SYMBOL_GPL(ubi_leb_read);

int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
          int offset, int len)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;
    int vol_id = vol->vol_id;

    dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);

    if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
        return -EINVAL;

    if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
        return -EROFS;

    if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 ||
        offset + len > vol->usable_leb_size ||
        offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
        return -EINVAL;

    if (vol->upd_marker)
        return -EBADF;

    if (len == 0)
        return 0;

    return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
}
EXPORT_SYMBOL_GPL(ubi_leb_write);

/*
 * ubi_leb_change - change logical eraseblock atomically.
 * @desc: volume descriptor
 * @lnum: logical eraseblock number to change
 * @buf: data to write
 * @len: how many bytes to write
 *
 * This function changes the contents of a logical eraseblock atomically. @buf
 * has to contain new logical eraseblock data, and @len - the length of the
 * data, which has to be aligned. The length may be shorter than the logical
 * eraseblock size, ant the logical eraseblock may be appended to more times
 * later on. This function guarantees that in case of an unclean reboot the old
 * contents is preserved. Returns zero in case of success and a negative error
 * code in case of failure.
 */
int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
           int len)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;
    int vol_id = vol->vol_id;

    dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);

    if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
        return -EINVAL;

    if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
        return -EROFS;

    if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 ||
        len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
        return -EINVAL;

    if (vol->upd_marker)
        return -EBADF;

    if (len == 0)
        return 0;

    return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
}
EXPORT_SYMBOL_GPL(ubi_leb_change);

int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;
    int err;

    dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);

    if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
        return -EROFS;

    if (lnum < 0 || lnum >= vol->reserved_pebs)
        return -EINVAL;

    if (vol->upd_marker)
        return -EBADF;

    err = ubi_eba_unmap_leb(ubi, vol, lnum);
    if (err)
        return err;

    return ubi_wl_flush(ubi, vol->vol_id, lnum);
}
EXPORT_SYMBOL_GPL(ubi_leb_erase);

int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;

    dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);

    if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
        return -EROFS;

    if (lnum < 0 || lnum >= vol->reserved_pebs)
        return -EINVAL;

    if (vol->upd_marker)
        return -EBADF;

    return ubi_eba_unmap_leb(ubi, vol, lnum);
}
EXPORT_SYMBOL_GPL(ubi_leb_unmap);

int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;

    dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);

    if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
        return -EROFS;

    if (lnum < 0 || lnum >= vol->reserved_pebs)
        return -EINVAL;

    if (vol->upd_marker)
        return -EBADF;

    if (vol->eba_tbl[lnum] >= 0)
        return -EBADMSG;

    return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
}
EXPORT_SYMBOL_GPL(ubi_leb_map);

int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
{
    struct ubi_volume *vol = desc->vol;

    dbg_gen("test LEB %d:%d", vol->vol_id, lnum);

    if (lnum < 0 || lnum >= vol->reserved_pebs)
        return -EINVAL;

    if (vol->upd_marker)
        return -EBADF;

    return vol->eba_tbl[lnum] >= 0;
}
EXPORT_SYMBOL_GPL(ubi_is_mapped);

int ubi_sync(int ubi_num)
{
    struct ubi_device *ubi;

    ubi = ubi_get_device(ubi_num);
    if (!ubi)
        return -ENODEV;

    mtd_sync(ubi->mtd);
    ubi_put_device(ubi);
    return 0;
}
EXPORT_SYMBOL_GPL(ubi_sync);

int ubi_flush(int ubi_num, int vol_id, int lnum)
{
    struct ubi_device *ubi;
    int err = 0;

    ubi = ubi_get_device(ubi_num);
    if (!ubi)
        return -ENODEV;

    err = ubi_wl_flush(ubi, vol_id, lnum);
    ubi_put_device(ubi);
    return err;
}
EXPORT_SYMBOL_GPL(ubi_flush);

BLOCKING_NOTIFIER_HEAD(ubi_notifiers);

int ubi_register_volume_notifier(struct notifier_block *nb,
                 int ignore_existing)
{
    int err;

    err = blocking_notifier_chain_register(&ubi_notifiers, nb);
    if (err != 0)
        return err;
    if (ignore_existing)
        return 0;

    /*
     * We are going to walk all UBI devices and all volumes, and
     * notify the user about existing volumes by the %UBI_VOLUME_ADDED
     * event. We have to lock the @ubi_devices_mutex to make sure UBI
     * devices do not disappear.
     */
    mutex_lock(&ubi_devices_mutex);
    ubi_enumerate_volumes(nb);
    mutex_unlock(&ubi_devices_mutex);

    return err;
}
EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);

int ubi_unregister_volume_notifier(struct notifier_block *nb)
{
    return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
}
EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);