vmt.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 contains implementation of volume creation, deletion, updating and
 * resizing.
 */

#include <linux/err.h>
#include <linux/math64.h>
#include <linux/slab.h>
#include <linux/export.h>
#include "ubi.h"

static int self_check_volumes(struct ubi_device *ubi);

static ssize_t vol_attribute_show(struct device *dev,
                  struct device_attribute *attr, char *buf);

/* Device attributes corresponding to files in '/<sysfs>/class/ubi/ubiX_Y' */
static struct device_attribute attr_vol_reserved_ebs =
    __ATTR(reserved_ebs, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_type =
    __ATTR(type, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_name =
    __ATTR(name, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_corrupted =
    __ATTR(corrupted, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_alignment =
    __ATTR(alignment, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_usable_eb_size =
    __ATTR(usable_eb_size, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_data_bytes =
    __ATTR(data_bytes, S_IRUGO, vol_attribute_show, NULL);
static struct device_attribute attr_vol_upd_marker =
    __ATTR(upd_marker, S_IRUGO, vol_attribute_show, NULL);

/*
 * "Show" method for files in '/<sysfs>/class/ubi/ubiX_Y/'.
 *
 * Consider a situation:
 * A. process 1 opens a sysfs file related to volume Y, say
 *    /<sysfs>/class/ubi/ubiX_Y/reserved_ebs;
 * B. process 2 removes volume Y;
 * C. process 1 starts reading the /<sysfs>/class/ubi/ubiX_Y/reserved_ebs file;
 *
 * In this situation, this function will return %-ENODEV because it will find
 * out that the volume was removed from the @ubi->volumes array.
 */
static ssize_t vol_attribute_show(struct device *dev,
                  struct device_attribute *attr, char *buf)
{
    int ret;
    struct ubi_volume *vol = container_of(dev, struct ubi_volume, dev);
    struct ubi_device *ubi;

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

    spin_lock(&ubi->volumes_lock);
    if (!ubi->volumes[vol->vol_id]) {
        spin_unlock(&ubi->volumes_lock);
        ubi_put_device(ubi);
        return -ENODEV;
    }
    /* Take a reference to prevent volume removal */
    vol->ref_count += 1;
    spin_unlock(&ubi->volumes_lock);

    if (attr == &attr_vol_reserved_ebs)
        ret = sprintf(buf, "%d\n", vol->reserved_pebs);
    else if (attr == &attr_vol_type) {
        const char *tp;

        if (vol->vol_type == UBI_DYNAMIC_VOLUME)
            tp = "dynamic";
        else
            tp = "static";
        ret = sprintf(buf, "%s\n", tp);
    } else if (attr == &attr_vol_name)
        ret = sprintf(buf, "%s\n", vol->name);
    else if (attr == &attr_vol_corrupted)
        ret = sprintf(buf, "%d\n", vol->corrupted);
    else if (attr == &attr_vol_alignment)
        ret = sprintf(buf, "%d\n", vol->alignment);
    else if (attr == &attr_vol_usable_eb_size)
        ret = sprintf(buf, "%d\n", vol->usable_leb_size);
    else if (attr == &attr_vol_data_bytes)
        ret = sprintf(buf, "%lld\n", vol->used_bytes);
    else if (attr == &attr_vol_upd_marker)
        ret = sprintf(buf, "%d\n", vol->upd_marker);
    else
        /* This must be a bug */
        ret = -EINVAL;

    /* We've done the operation, drop volume and UBI device references */
    spin_lock(&ubi->volumes_lock);
    vol->ref_count -= 1;
    ubi_assert(vol->ref_count >= 0);
    spin_unlock(&ubi->volumes_lock);
    ubi_put_device(ubi);
    return ret;
}

/* Release method for volume devices */
static void vol_release(struct device *dev)
{
    struct ubi_volume *vol = container_of(dev, struct ubi_volume, dev);

    kfree(vol->eba_tbl);
    kfree(vol);
}

static int volume_sysfs_init(struct ubi_device *ubi, struct ubi_volume *vol)
{
    int err;

    err = device_create_file(&vol->dev, &attr_vol_reserved_ebs);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_type);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_name);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_corrupted);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_alignment);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_usable_eb_size);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_data_bytes);
    if (err)
        return err;
    err = device_create_file(&vol->dev, &attr_vol_upd_marker);
    return err;
}

static void volume_sysfs_close(struct ubi_volume *vol)
{
    device_remove_file(&vol->dev, &attr_vol_upd_marker);
    device_remove_file(&vol->dev, &attr_vol_data_bytes);
    device_remove_file(&vol->dev, &attr_vol_usable_eb_size);
    device_remove_file(&vol->dev, &attr_vol_alignment);
    device_remove_file(&vol->dev, &attr_vol_corrupted);
    device_remove_file(&vol->dev, &attr_vol_name);
    device_remove_file(&vol->dev, &attr_vol_type);
    device_remove_file(&vol->dev, &attr_vol_reserved_ebs);
    device_unregister(&vol->dev);
}

int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
{
    int i, err, vol_id = req->vol_id, do_free = 1;
    struct ubi_volume *vol;
    struct ubi_vtbl_record vtbl_rec;
    dev_t dev;

    if (ubi->ro_mode)
        return -EROFS;

    vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
    if (!vol)
        return -ENOMEM;

    spin_lock(&ubi->volumes_lock);
    if (vol_id == UBI_VOL_NUM_AUTO) {
        /* Find unused volume ID */
        dbg_gen("search for vacant volume ID");
        for (i = 0; i < ubi->vtbl_slots; i++)
            if (!ubi->volumes[i]) {
                vol_id = i;
                break;
            }

        if (vol_id == UBI_VOL_NUM_AUTO) {
            ubi_err("out of volume IDs");
            err = -ENFILE;
            goto out_unlock;
        }
        req->vol_id = vol_id;
    }

    dbg_gen("create device %d, volume %d, %llu bytes, type %d, name %s",
        ubi->ubi_num, vol_id, (unsigned long long)req->bytes,
        (int)req->vol_type, req->name);

    /* Ensure that this volume does not exist */
    err = -EEXIST;
    if (ubi->volumes[vol_id]) {
        ubi_err("volume %d already exists", vol_id);
        goto out_unlock;
    }

    /* Ensure that the name is unique */
    for (i = 0; i < ubi->vtbl_slots; i++)
        if (ubi->volumes[i] &&
            ubi->volumes[i]->name_len == req->name_len &&
            !strcmp(ubi->volumes[i]->name, req->name)) {
            ubi_err("volume \"%s\" exists (ID %d)", req->name, i);
            goto out_unlock;
        }

    /* Calculate how many eraseblocks are requested */
    vol->usable_leb_size = ubi->leb_size - ubi->leb_size % req->alignment;
    vol->reserved_pebs += div_u64(req->bytes + vol->usable_leb_size - 1,
                      vol->usable_leb_size);

    /* Reserve physical eraseblocks */
    if (vol->reserved_pebs > ubi->avail_pebs) {
        ubi_err("not enough PEBs, only %d available", ubi->avail_pebs);
        if (ubi->corr_peb_count)
            ubi_err("%d PEBs are corrupted and not used",
                ubi->corr_peb_count);
        err = -ENOSPC;
        goto out_unlock;
    }
    ubi->avail_pebs -= vol->reserved_pebs;
    ubi->rsvd_pebs += vol->reserved_pebs;
    spin_unlock(&ubi->volumes_lock);

    vol->vol_id    = vol_id;
    vol->alignment = req->alignment;
    vol->data_pad  = ubi->leb_size % vol->alignment;
    vol->vol_type  = req->vol_type;
    vol->name_len  = req->name_len;
    memcpy(vol->name, req->name, vol->name_len);
    vol->ubi = ubi;

    /*
     * Finish all pending erases because there may be some LEBs belonging
     * to the same volume ID.
     */
    err = ubi_wl_flush(ubi, vol_id, UBI_ALL);
    if (err)
        goto out_acc;

    vol->eba_tbl = kmalloc(vol->reserved_pebs * sizeof(int), GFP_KERNEL);
    if (!vol->eba_tbl) {
        err = -ENOMEM;
        goto out_acc;
    }

    for (i = 0; i < vol->reserved_pebs; i++)
        vol->eba_tbl[i] = UBI_LEB_UNMAPPED;

    if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
        vol->used_ebs = vol->reserved_pebs;
        vol->last_eb_bytes = vol->usable_leb_size;
        vol->used_bytes =
            (long long)vol->used_ebs * vol->usable_leb_size;
    } else {
        vol->used_ebs = div_u64_rem(vol->used_bytes,
                        vol->usable_leb_size,
                        &vol->last_eb_bytes);
        if (vol->last_eb_bytes != 0)
            vol->used_ebs += 1;
        else
            vol->last_eb_bytes = vol->usable_leb_size;
    }

    /* Register character device for the volume */
    cdev_init(&vol->cdev, &ubi_vol_cdev_operations);
    vol->cdev.owner = THIS_MODULE;
    dev = MKDEV(MAJOR(ubi->cdev.dev), vol_id + 1);
    err = cdev_add(&vol->cdev, dev, 1);
    if (err) {
        ubi_err("cannot add character device");
        goto out_mapping;
    }

    vol->dev.release = vol_release;
    vol->dev.parent = &ubi->dev;
    vol->dev.devt = dev;
    vol->dev.class = ubi_class;

    dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
    err = device_register(&vol->dev);
    if (err) {
        ubi_err("cannot register device");
        goto out_cdev;
    }

    err = volume_sysfs_init(ubi, vol);
    if (err)
        goto out_sysfs;

    /* Fill volume table record */
    memset(&vtbl_rec, 0, sizeof(struct ubi_vtbl_record));
    vtbl_rec.reserved_pebs = cpu_to_be32(vol->reserved_pebs);
    vtbl_rec.alignment     = cpu_to_be32(vol->alignment);
    vtbl_rec.data_pad      = cpu_to_be32(vol->data_pad);
    vtbl_rec.name_len      = cpu_to_be16(vol->name_len);
    if (vol->vol_type == UBI_DYNAMIC_VOLUME)
        vtbl_rec.vol_type = UBI_VID_DYNAMIC;
    else
        vtbl_rec.vol_type = UBI_VID_STATIC;
    memcpy(vtbl_rec.name, vol->name, vol->name_len);

    err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
    if (err)
        goto out_sysfs;

    spin_lock(&ubi->volumes_lock);
    ubi->volumes[vol_id] = vol;
    ubi->vol_count += 1;
    spin_unlock(&ubi->volumes_lock);

    ubi_volume_notify(ubi, vol, UBI_VOLUME_ADDED);
    self_check_volumes(ubi);
    return err;

out_sysfs:
    /*
     * We have registered our device, we should not free the volume
     * description object in this function in case of an error - it is
     * freed by the release function.
     *
     * Get device reference to prevent the release function from being
     * called just after sysfs has been closed.
     */
    do_free = 0;
    get_device(&vol->dev);
    volume_sysfs_close(vol);
out_cdev:
    cdev_del(&vol->cdev);
out_mapping:
    if (do_free)
        kfree(vol->eba_tbl);
out_acc:
    spin_lock(&ubi->volumes_lock);
    ubi->rsvd_pebs -= vol->reserved_pebs;
    ubi->avail_pebs += vol->reserved_pebs;
out_unlock:
    spin_unlock(&ubi->volumes_lock);
    if (do_free)
        kfree(vol);
    else
        put_device(&vol->dev);
    ubi_err("cannot create volume %d, error %d", vol_id, err);
    return err;
}

int ubi_remove_volume(struct ubi_volume_desc *desc, int no_vtbl)
{
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;
    int i, err, vol_id = vol->vol_id, reserved_pebs = vol->reserved_pebs;

    dbg_gen("remove device %d, volume %d", ubi->ubi_num, vol_id);
    ubi_assert(desc->mode == UBI_EXCLUSIVE);
    ubi_assert(vol == ubi->volumes[vol_id]);

    if (ubi->ro_mode)
        return -EROFS;

    spin_lock(&ubi->volumes_lock);
    if (vol->ref_count > 1) {
        /*
         * The volume is busy, probably someone is reading one of its
         * sysfs files.
         */
        err = -EBUSY;
        goto out_unlock;
    }
    ubi->volumes[vol_id] = NULL;
    spin_unlock(&ubi->volumes_lock);

    if (!no_vtbl) {
        err = ubi_change_vtbl_record(ubi, vol_id, NULL);
        if (err)
            goto out_err;
    }

    for (i = 0; i < vol->reserved_pebs; i++) {
        err = ubi_eba_unmap_leb(ubi, vol, i);
        if (err)
            goto out_err;
    }

    cdev_del(&vol->cdev);
    volume_sysfs_close(vol);

    spin_lock(&ubi->volumes_lock);
    ubi->rsvd_pebs -= reserved_pebs;
    ubi->avail_pebs += reserved_pebs;
    ubi_update_reserved(ubi);
    ubi->vol_count -= 1;
    spin_unlock(&ubi->volumes_lock);

    ubi_volume_notify(ubi, vol, UBI_VOLUME_REMOVED);
    if (!no_vtbl)
        self_check_volumes(ubi);

    return err;

out_err:
    ubi_err("cannot remove volume %d, error %d", vol_id, err);
    spin_lock(&ubi->volumes_lock);
    ubi->volumes[vol_id] = vol;
out_unlock:
    spin_unlock(&ubi->volumes_lock);
    return err;
}

int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
{
    int i, err, pebs, *new_mapping;
    struct ubi_volume *vol = desc->vol;
    struct ubi_device *ubi = vol->ubi;
    struct ubi_vtbl_record vtbl_rec;
    int vol_id = vol->vol_id;

    if (ubi->ro_mode)
        return -EROFS;

    dbg_gen("re-size device %d, volume %d to from %d to %d PEBs",
        ubi->ubi_num, vol_id, vol->reserved_pebs, reserved_pebs);

    if (vol->vol_type == UBI_STATIC_VOLUME &&
        reserved_pebs < vol->used_ebs) {
        ubi_err("too small size %d, %d LEBs contain data",
            reserved_pebs, vol->used_ebs);
        return -EINVAL;
    }

    /* If the size is the same, we have nothing to do */
    if (reserved_pebs == vol->reserved_pebs)
        return 0;

    new_mapping = kmalloc(reserved_pebs * sizeof(int), GFP_KERNEL);
    if (!new_mapping)
        return -ENOMEM;

    for (i = 0; i < reserved_pebs; i++)
        new_mapping[i] = UBI_LEB_UNMAPPED;

    spin_lock(&ubi->volumes_lock);
    if (vol->ref_count > 1) {
        spin_unlock(&ubi->volumes_lock);
        err = -EBUSY;
        goto out_free;
    }
    spin_unlock(&ubi->volumes_lock);

    /* Reserve physical eraseblocks */
    pebs = reserved_pebs - vol->reserved_pebs;
    if (pebs > 0) {
        spin_lock(&ubi->volumes_lock);
        if (pebs > ubi->avail_pebs) {
            ubi_err("not enough PEBs: requested %d, available %d",
                pebs, ubi->avail_pebs);
            if (ubi->corr_peb_count)
                ubi_err("%d PEBs are corrupted and not used",
                    ubi->corr_peb_count);
            spin_unlock(&ubi->volumes_lock);
            err = -ENOSPC;
            goto out_free;
        }
        ubi->avail_pebs -= pebs;
        ubi->rsvd_pebs += pebs;
        for (i = 0; i < vol->reserved_pebs; i++)
            new_mapping[i] = vol->eba_tbl[i];
        kfree(vol->eba_tbl);
        vol->eba_tbl = new_mapping;
        spin_unlock(&ubi->volumes_lock);
    }

    /* Change volume table record */
    memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
    vtbl_rec.reserved_pebs = cpu_to_be32(reserved_pebs);
    err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
    if (err)
        goto out_acc;

    if (pebs < 0) {
        for (i = 0; i < -pebs; i++) {
            err = ubi_eba_unmap_leb(ubi, vol, reserved_pebs + i);
            if (err)
                goto out_acc;
        }
        spin_lock(&ubi->volumes_lock);
        ubi->rsvd_pebs += pebs;
        ubi->avail_pebs -= pebs;
        ubi_update_reserved(ubi);
        for (i = 0; i < reserved_pebs; i++)
            new_mapping[i] = vol->eba_tbl[i];
        kfree(vol->eba_tbl);
        vol->eba_tbl = new_mapping;
        spin_unlock(&ubi->volumes_lock);
    }

    vol->reserved_pebs = reserved_pebs;
    if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
        vol->used_ebs = reserved_pebs;
        vol->last_eb_bytes = vol->usable_leb_size;
        vol->used_bytes =
            (long long)vol->used_ebs * vol->usable_leb_size;
    }

    ubi_volume_notify(ubi, vol, UBI_VOLUME_RESIZED);
    self_check_volumes(ubi);
    return err;

out_acc:
    if (pebs > 0) {
        spin_lock(&ubi->volumes_lock);
        ubi->rsvd_pebs -= pebs;
        ubi->avail_pebs += pebs;
        spin_unlock(&ubi->volumes_lock);
    }
out_free:
    kfree(new_mapping);
    return err;
}

int ubi_rename_volumes(struct ubi_device *ubi, struct list_head *rename_list)
{
    int err;
    struct ubi_rename_entry *re;

    err = ubi_vtbl_rename_volumes(ubi, rename_list);
    if (err)
        return err;

    list_for_each_entry(re, rename_list, list) {
        if (re->remove) {
            err = ubi_remove_volume(re->desc, 1);
            if (err)
                break;
        } else {
            struct ubi_volume *vol = re->desc->vol;

            spin_lock(&ubi->volumes_lock);
            vol->name_len = re->new_name_len;
            memcpy(vol->name, re->new_name, re->new_name_len + 1);
            spin_unlock(&ubi->volumes_lock);
            ubi_volume_notify(ubi, vol, UBI_VOLUME_RENAMED);
        }
    }

    if (!err)
        self_check_volumes(ubi);
    return err;
}

int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
{
    int err, vol_id = vol->vol_id;
    dev_t dev;

    dbg_gen("add volume %d", vol_id);

    /* Register character device for the volume */
    cdev_init(&vol->cdev, &ubi_vol_cdev_operations);
    vol->cdev.owner = THIS_MODULE;
    dev = MKDEV(MAJOR(ubi->cdev.dev), vol->vol_id + 1);
    err = cdev_add(&vol->cdev, dev, 1);
    if (err) {
        ubi_err("cannot add character device for volume %d, error %d",
            vol_id, err);
        return err;
    }

    vol->dev.release = vol_release;
    vol->dev.parent = &ubi->dev;
    vol->dev.devt = dev;
    vol->dev.class = ubi_class;
    dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
    err = device_register(&vol->dev);
    if (err)
        goto out_cdev;

    err = volume_sysfs_init(ubi, vol);
    if (err) {
        cdev_del(&vol->cdev);
        volume_sysfs_close(vol);
        return err;
    }

    self_check_volumes(ubi);
    return err;

out_cdev:
    cdev_del(&vol->cdev);
    return err;
}

void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol)
{
    dbg_gen("free volume %d", vol->vol_id);

    ubi->volumes[vol->vol_id] = NULL;
    cdev_del(&vol->cdev);
    volume_sysfs_close(vol);
}

static int self_check_volume(struct ubi_device *ubi, int vol_id)
{
    int idx = vol_id2idx(ubi, vol_id);
    int reserved_pebs, alignment, data_pad, vol_type, name_len, upd_marker;
    const struct ubi_volume *vol;
    long long n;
    const char *name;

    spin_lock(&ubi->volumes_lock);
    reserved_pebs = be32_to_cpu(ubi->vtbl[vol_id].reserved_pebs);
    vol = ubi->volumes[idx];

    if (!vol) {
        if (reserved_pebs) {
            ubi_err("no volume info, but volume exists");
            goto fail;
        }
        spin_unlock(&ubi->volumes_lock);
        return 0;
    }

    if (vol->reserved_pebs < 0 || vol->alignment < 0 || vol->data_pad < 0 ||
        vol->name_len < 0) {
        ubi_err("negative values");
        goto fail;
    }
    if (vol->alignment > ubi->leb_size || vol->alignment == 0) {
        ubi_err("bad alignment");
        goto fail;
    }

    n = vol->alignment & (ubi->min_io_size - 1);
    if (vol->alignment != 1 && n) {
        ubi_err("alignment is not multiple of min I/O unit");
        goto fail;
    }

    n = ubi->leb_size % vol->alignment;
    if (vol->data_pad != n) {
        ubi_err("bad data_pad, has to be %lld", n);
        goto fail;
    }

    if (vol->vol_type != UBI_DYNAMIC_VOLUME &&
        vol->vol_type != UBI_STATIC_VOLUME) {
        ubi_err("bad vol_type");
        goto fail;
    }

    if (vol->upd_marker && vol->corrupted) {
        ubi_err("update marker and corrupted simultaneously");
        goto fail;
    }

    if (vol->reserved_pebs > ubi->good_peb_count) {
        ubi_err("too large reserved_pebs");
        goto fail;
    }

    n = ubi->leb_size - vol->data_pad;
    if (vol->usable_leb_size != ubi->leb_size - vol->data_pad) {
        ubi_err("bad usable_leb_size, has to be %lld", n);
        goto fail;
    }

    if (vol->name_len > UBI_VOL_NAME_MAX) {
        ubi_err("too long volume name, max is %d", UBI_VOL_NAME_MAX);
        goto fail;
    }

    n = strnlen(vol->name, vol->name_len + 1);
    if (n != vol->name_len) {
        ubi_err("bad name_len %lld", n);
        goto fail;
    }

    n = (long long)vol->used_ebs * vol->usable_leb_size;
    if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
        if (vol->corrupted) {
            ubi_err("corrupted dynamic volume");
            goto fail;
        }
        if (vol->used_ebs != vol->reserved_pebs) {
            ubi_err("bad used_ebs");
            goto fail;
        }
        if (vol->last_eb_bytes != vol->usable_leb_size) {
            ubi_err("bad last_eb_bytes");
            goto fail;
        }
        if (vol->used_bytes != n) {
            ubi_err("bad used_bytes");
            goto fail;
        }
    } else {
        if (vol->used_ebs < 0 || vol->used_ebs > vol->reserved_pebs) {
            ubi_err("bad used_ebs");
            goto fail;
        }
        if (vol->last_eb_bytes < 0 ||
            vol->last_eb_bytes > vol->usable_leb_size) {
            ubi_err("bad last_eb_bytes");
            goto fail;
        }
        if (vol->used_bytes < 0 || vol->used_bytes > n ||
            vol->used_bytes < n - vol->usable_leb_size) {
            ubi_err("bad used_bytes");
            goto fail;
        }
    }

    alignment  = be32_to_cpu(ubi->vtbl[vol_id].alignment);
    data_pad   = be32_to_cpu(ubi->vtbl[vol_id].data_pad);
    name_len   = be16_to_cpu(ubi->vtbl[vol_id].name_len);
    upd_marker = ubi->vtbl[vol_id].upd_marker;
    name       = &ubi->vtbl[vol_id].name[0];
    if (ubi->vtbl[vol_id].vol_type == UBI_VID_DYNAMIC)
        vol_type = UBI_DYNAMIC_VOLUME;
    else
        vol_type = UBI_STATIC_VOLUME;

    if (alignment != vol->alignment || data_pad != vol->data_pad ||
        upd_marker != vol->upd_marker || vol_type != vol->vol_type ||
        name_len != vol->name_len || strncmp(name, vol->name, name_len)) {
        ubi_err("volume info is different");
        goto fail;
    }

    spin_unlock(&ubi->volumes_lock);
    return 0;

fail:
    ubi_err("self-check failed for volume %d", vol_id);
    if (vol)
        ubi_dump_vol_info(vol);
    ubi_dump_vtbl_record(&ubi->vtbl[vol_id], vol_id);
    dump_stack();
    spin_unlock(&ubi->volumes_lock);
    return -EINVAL;
}

static int self_check_volumes(struct ubi_device *ubi)
{
    int i, err = 0;

    if (!ubi->dbg->chk_gen)
        return 0;

    for (i = 0; i < ubi->vtbl_slots; i++) {
        err = self_check_volume(ubi, i);
        if (err)
            break;
    }

    return err;
}