Committer: Michael Beasley <mike@snafu.setup>

[mikesnafu-overlay.git] / drivers / mtd / ubi / vmt.c

/*
 * 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 <asm/div64.h>
#include "ubi.h"

#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID
static void paranoid_check_volumes(struct ubi_device *ubi);
#else
#define paranoid_check_volumes(ubi)
#endif

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);
}

/**
 * volume_sysfs_init - initialize sysfs for new volume.
 * @ubi: UBI device description object
 * @vol: volume description object
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 *
 * Note, this function does not free allocated resources in case of failure -
 * the caller does it. This is because this would cause release() here and the
 * caller would oops.
 */
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;
}

/**
 * volume_sysfs_close - close sysfs for a volume.
 * @vol: volume description object
 */
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);
}

/**
 * ubi_create_volume - create volume.
 * @ubi: UBI device description object
 * @req: volume creation request
 *
 * This function creates volume described by @req. If @req->vol_id id
 * %UBI_VOL_NUM_AUTO, this function automatically assign ID to the new volume
 * and saves it in @req->vol_id. Returns zero in case of success and a negative
 * error code in case of failure. Note, the caller has to have the
 * @ubi->volumes_mutex locked.
 */
int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
{
        int i, err, vol_id = req->vol_id, dont_free = 0;
        struct ubi_volume *vol;
        struct ubi_vtbl_record vtbl_rec;
        uint64_t bytes;
        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_msg("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) {
                        dbg_err("out of volume IDs");
                        err = -ENFILE;
                        goto out_unlock;
                }
                req->vol_id = vol_id;
        }

        dbg_msg("volume ID %d, %llu bytes, type %d, name %s",
                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]) {
                dbg_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)) {
                        dbg_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;
        bytes = req->bytes;
        if (do_div(bytes, vol->usable_leb_size))
                vol->reserved_pebs = 1;
        vol->reserved_pebs += bytes;

        /* Reserve physical eraseblocks */
        if (vol->reserved_pebs > ubi->avail_pebs) {
                dbg_err("not enough PEBs, only %d available", ubi->avail_pebs);
                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 + 1);
        vol->ubi = ubi;

        /*
         * Finish all pending erases because there may be some LEBs belonging
         * to the same volume ID.
         */
        err = ubi_wl_flush(ubi);
        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 {
                bytes = vol->used_bytes;
                vol->last_eb_bytes = do_div(bytes, vol->usable_leb_size);
                vol->used_ebs = bytes;
                if (vol->last_eb_bytes)
                        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;
        }

        err = ubi_create_gluebi(ubi, vol);
        if (err)
                goto out_cdev;

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

        sprintf(&vol->dev.bus_id[0], "%s_%d", ubi->ubi_name, vol->vol_id);
        err = device_register(&vol->dev);
        if (err) {
                ubi_err("cannot register device");
                goto out_gluebi;
        }

        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 + 1);

        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);

        paranoid_check_volumes(ubi);
        return 0;

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.
         */
        dont_free = 1;
        get_device(&vol->dev);
        volume_sysfs_close(vol);
out_gluebi:
        if (ubi_destroy_gluebi(vol))
                dbg_err("cannot destroy gluebi for volume %d:%d",
                        ubi->ubi_num, vol_id);
out_cdev:
        cdev_del(&vol->cdev);
out_mapping:
        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 (dont_free)
                put_device(&vol->dev);
        else
                kfree(vol);
        ubi_err("cannot create volume %d, error %d", vol_id, err);
        return err;
}

/**
 * ubi_remove_volume - remove volume.
 * @desc: volume descriptor
 *
 * This function removes volume described by @desc. The volume has to be opened
 * in "exclusive" mode. Returns zero in case of success and a negative error
 * code in case of failure. The caller has to have the @ubi->volumes_mutex
 * locked.
 */
int ubi_remove_volume(struct ubi_volume_desc *desc)
{
        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_msg("remove UBI volume %d", 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);

        err = ubi_destroy_gluebi(vol);
        if (err)
                goto out_err;

        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;
        }

        kfree(vol->eba_tbl);
        vol->eba_tbl = NULL;
        cdev_del(&vol->cdev);
        volume_sysfs_close(vol);

        spin_lock(&ubi->volumes_lock);
        ubi->rsvd_pebs -= reserved_pebs;
        ubi->avail_pebs += reserved_pebs;
        i = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
        if (i > 0) {
                i = ubi->avail_pebs >= i ? i : ubi->avail_pebs;
                ubi->avail_pebs -= i;
                ubi->rsvd_pebs += i;
                ubi->beb_rsvd_pebs += i;
                if (i > 0)
                        ubi_msg("reserve more %d PEBs", i);
        }
        ubi->vol_count -= 1;
        spin_unlock(&ubi->volumes_lock);

        paranoid_check_volumes(ubi);
        return 0;

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;
}

/**
 * ubi_resize_volume - re-size volume.
 * @desc: volume descriptor
 * @reserved_pebs: new size in physical eraseblocks
 *
 * This function re-sizes the volume and returns zero in case of success, and a
 * negative error code in case of failure. The caller has to have the
 * @ubi->volumes_mutex locked.
 */
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_msg("re-size volume %d to from %d to %d PEBs",
                vol_id, vol->reserved_pebs, reserved_pebs);

        if (vol->vol_type == UBI_STATIC_VOLUME &&
            reserved_pebs < vol->used_ebs) {
                dbg_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) {
                        dbg_err("not enough PEBs: requested %d, available %d",
                                pebs, ubi->avail_pebs);
                        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;
                pebs = ubi->beb_rsvd_level - ubi->beb_rsvd_pebs;
                if (pebs > 0) {
                        pebs = ubi->avail_pebs >= pebs ? pebs : ubi->avail_pebs;
                        ubi->avail_pebs -= pebs;
                        ubi->rsvd_pebs += pebs;
                        ubi->beb_rsvd_pebs += pebs;
                        if (pebs > 0)
                                ubi_msg("reserve more %d PEBs", pebs);
                }
                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;
        }

        paranoid_check_volumes(ubi);
        return 0;

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;
}

/**
 * ubi_add_volume - add volume.
 * @ubi: UBI device description object
 * @vol: volume description object
 *
 * This function adds an existing volume and initializes all its data
 * structures. Returns zero in case of success and a negative error code in
 * case of failure.
 */
int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol)
{
        int err, vol_id = vol->vol_id;
        dev_t dev;

        dbg_msg("add volume %d", vol_id);
        ubi_dbg_dump_vol_info(vol);

        /* 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;
        }

        err = ubi_create_gluebi(ubi, vol);
        if (err)
                goto out_cdev;

        vol->dev.release = vol_release;
        vol->dev.parent = &ubi->dev;
        vol->dev.devt = dev;
        vol->dev.class = ubi_class;
        sprintf(&vol->dev.bus_id[0], "%s_%d", ubi->ubi_name, vol->vol_id);
        err = device_register(&vol->dev);
        if (err)
                goto out_gluebi;

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

        paranoid_check_volumes(ubi);
        return 0;

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

/**
 * ubi_free_volume - free volume.
 * @ubi: UBI device description object
 * @vol: volume description object
 *
 * This function frees all resources for volume @vol but does not remove it.
 * Used only when the UBI device is detached.
 */
void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol)
{
        int err;

        dbg_msg("free volume %d", vol->vol_id);

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

#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID

/**
 * paranoid_check_volume - check volume information.
 * @ubi: UBI device description object
 * @vol_id: volume ID
 */
static void paranoid_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;
        }

        if (vol->exclusive) {
                /*
                 * The volume may be being created at the moment, do not check
                 * it (e.g., it may be in the middle of ubi_create_volume().
                 */
                spin_unlock(&ubi->volumes_lock);
                return;
        }

        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;
        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) {
                dbg_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;
        }

        if (!vol->name) {
                ubi_err("NULL volume name");
                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;

fail:
        ubi_err("paranoid check failed for volume %d", vol_id);
        ubi_dbg_dump_vol_info(vol);
        ubi_dbg_dump_vtbl_record(&ubi->vtbl[vol_id], vol_id);
        spin_unlock(&ubi->volumes_lock);
        BUG();
}

/**
 * paranoid_check_volumes - check information about all volumes.
 * @ubi: UBI device description object
 */
static void paranoid_check_volumes(struct ubi_device *ubi)
{
        int i;

        for (i = 0; i < ubi->vtbl_slots; i++)
                paranoid_check_volume(ubi, i);
}
#endif