// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * 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 = vol->ubi;

        spin_lock(&ubi->volumes_lock);
        if (!ubi->volumes[vol->vol_id] || ubi->volumes[vol->vol_id]->is_dead) {
                spin_unlock(&ubi->volumes_lock);
                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);
        return ret;
}

static struct attribute *volume_dev_attrs[] = {
        &attr_vol_reserved_ebs.attr,
        &attr_vol_type.attr,
        &attr_vol_name.attr,
        &attr_vol_corrupted.attr,
        &attr_vol_alignment.attr,
        &attr_vol_usable_eb_size.attr,
        &attr_vol_data_bytes.attr,
        &attr_vol_upd_marker.attr,
        NULL
};
ATTRIBUTE_GROUPS(volume_dev);

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

        ubi_eba_replace_table(vol, NULL);
        ubi_fastmap_destroy_checkmap(vol);
        kfree(vol);
}

static struct fwnode_handle *find_volume_fwnode(struct ubi_volume *vol)
{
        struct fwnode_handle *fw_vols, *fw_vol;
        const char *volname;
        u32 volid;

        fw_vols = device_get_named_child_node(vol->dev.parent->parent, "volumes");
        if (!fw_vols)
                return NULL;

        fwnode_for_each_child_node(fw_vols, fw_vol) {
                if (!fwnode_property_read_string(fw_vol, "volname", &volname) &&
                    strncmp(volname, vol->name, vol->name_len))
                        continue;

                if (!fwnode_property_read_u32(fw_vol, "volid", &volid) &&
                    vol->vol_id != volid)
                        continue;

                fwnode_handle_put(fw_vols);
                return fw_vol;
        }
        fwnode_handle_put(fw_vols);

        return NULL;
}

/**
 * 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->device_mutex locked.
 */
int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
{
        int i, err, vol_id = req->vol_id;
        struct ubi_volume *vol;
        struct ubi_vtbl_record vtbl_rec;
        struct ubi_eba_table *eba_tbl = NULL;

        if (ubi->ro_mode)
                return -EROFS;

        vol = kzalloc_obj(struct ubi_volume);
        if (!vol)
                return -ENOMEM;

        device_initialize(&vol->dev);
        vol->dev.release = vol_release;
        vol->dev.parent = &ubi->dev;
        vol->dev.class = &ubi_class;
        vol->dev.groups = volume_dev_groups;

        if (req->flags & UBI_VOL_SKIP_CRC_CHECK_FLG)
                vol->skip_check = 1;

        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(ubi, "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(ubi, "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]->is_dead &&
                    ubi->volumes[i]->name_len == req->name_len &&
                    !strcmp(ubi->volumes[i]->name, req->name)) {
                        ubi_err(ubi, "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(ubi, "not enough PEBs, only %d available",
                        ubi->avail_pebs);
                if (ubi->corr_peb_count)
                        ubi_err(ubi, "%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;
        device_set_node(&vol->dev, find_volume_fwnode(vol));

        /*
         * 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;

        eba_tbl = ubi_eba_create_table(vol, vol->reserved_pebs);
        if (IS_ERR(eba_tbl)) {
                err = PTR_ERR(eba_tbl);
                goto out_acc;
        }

        ubi_eba_replace_table(vol, eba_tbl);

        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;
        }

        /* Make volume "available" before it becomes accessible via sysfs */
        spin_lock(&ubi->volumes_lock);
        ubi->volumes[vol_id] = vol;
        ubi->vol_count += 1;
        spin_unlock(&ubi->volumes_lock);

        /* Register character device for the volume */
        cdev_init(&vol->cdev, &ubi_vol_cdev_operations);
        vol->cdev.owner = THIS_MODULE;

        vol->dev.devt = MKDEV(MAJOR(ubi->cdev.dev), vol_id + 1);
        dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
        err = cdev_device_add(&vol->cdev, &vol->dev);
        if (err) {
                ubi_err(ubi, "cannot add device");
                goto out_mapping;
        }

        /* 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;

        if (vol->skip_check)
                vtbl_rec.flags |= UBI_VTBL_SKIP_CRC_CHECK_FLG;

        memcpy(vtbl_rec.name, vol->name, vol->name_len);

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

        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.
         */
        cdev_device_del(&vol->cdev, &vol->dev);
out_mapping:
        spin_lock(&ubi->volumes_lock);
        ubi->volumes[vol_id] = NULL;
        ubi->vol_count -= 1;
        spin_unlock(&ubi->volumes_lock);
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);
        put_device(&vol->dev);
        ubi_err(ubi, "cannot create volume %d, error %d", vol_id, err);
        return err;
}

/**
 * ubi_remove_volume - remove volume.
 * @desc: volume descriptor
 * @no_vtbl: do not change volume table if not zero
 *
 * 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->device_mutex
 * locked.
 */
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;
        }

        /*
         * Mark volume as dead at this point to prevent that anyone
         * can take a reference to the volume from now on.
         * This is necessary as we have to release the spinlock before
         * calling ubi_volume_notify.
         */
        vol->is_dead = true;
        spin_unlock(&ubi->volumes_lock);

        ubi_volume_notify(ubi, vol, UBI_VOLUME_SHUTDOWN);

        spin_lock(&ubi->volumes_lock);
        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_device_del(&vol->cdev, &vol->dev);
        put_device(&vol->dev);

        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 0;

out_err:
        ubi_err(ubi, "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->device_mutex locked.
 */
int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
{
        int i, err, pebs;
        struct ubi_volume *vol = desc->vol;
        struct ubi_device *ubi = vol->ubi;
        struct ubi_vtbl_record vtbl_rec;
        struct ubi_eba_table *new_eba_tbl = NULL;
        struct ubi_eba_table *old_eba_tbl = NULL;
        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(ubi, "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_eba_tbl = ubi_eba_create_table(vol, reserved_pebs);
        if (IS_ERR(new_eba_tbl))
                return PTR_ERR(new_eba_tbl);

        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(ubi, "not enough PEBs: requested %d, available %d",
                                pebs, ubi->avail_pebs);
                        if (ubi->corr_peb_count)
                                ubi_err(ubi, "%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;
                ubi_eba_copy_table(vol, new_eba_tbl, vol->reserved_pebs);
                old_eba_tbl = vol->eba_tbl;
                vol->eba_tbl = new_eba_tbl;
                vol->reserved_pebs = reserved_pebs;
                spin_unlock(&ubi->volumes_lock);
        }

        if (pebs < 0) {
                for (i = 0; i < -pebs; i++) {
                        err = ubi_eba_unmap_leb(ubi, vol, reserved_pebs + i);
                        if (err)
                                goto out_free;
                }
                spin_lock(&ubi->volumes_lock);
                ubi->rsvd_pebs += pebs;
                ubi->avail_pebs -= pebs;
                ubi_update_reserved(ubi);
                ubi_eba_copy_table(vol, new_eba_tbl, reserved_pebs);
                old_eba_tbl = vol->eba_tbl;
                vol->eba_tbl = new_eba_tbl;
                vol->reserved_pebs = reserved_pebs;
                spin_unlock(&ubi->volumes_lock);
        }

        /*
         * When we shrink a volume we have to flush all pending (erase) work.
         * Otherwise it can happen that upon next attach UBI finds a LEB with
         * lnum > highest_lnum and refuses to attach.
         */
        if (pebs < 0) {
                err = ubi_wl_flush(ubi, vol_id, UBI_ALL);
                if (err)
                        goto out_acc;
        }

        /* Change volume table record */
        vtbl_rec = ubi->vtbl[vol_id];
        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 (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;
        }

        /* destroy old table */
        ubi_eba_destroy_table(old_eba_tbl);
        ubi_volume_notify(ubi, vol, UBI_VOLUME_RESIZED);
        self_check_volumes(ubi);
        return err;

out_acc:
        spin_lock(&ubi->volumes_lock);
        vol->reserved_pebs = reserved_pebs - pebs;
        ubi->rsvd_pebs -= pebs;
        ubi->avail_pebs += pebs;
        if (pebs > 0)
                ubi_eba_copy_table(vol, old_eba_tbl, vol->reserved_pebs);
        else
                ubi_eba_copy_table(vol, old_eba_tbl, reserved_pebs);
        vol->eba_tbl = old_eba_tbl;
        spin_unlock(&ubi->volumes_lock);
out_free:
        ubi_eba_destroy_table(new_eba_tbl);
        return err;
}

/**
 * ubi_rename_volumes - re-name UBI volumes.
 * @ubi: UBI device description object
 * @rename_list: list of &struct ubi_rename_entry objects
 *
 * This function re-names or removes volumes specified in the re-name list.
 * Returns zero in case of success and a negative error code in case of
 * failure.
 */
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;
}

/**
 * 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_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(ubi, "cannot add character device for volume %d, error %d",
                        vol_id, err);
                vol_release(&vol->dev);
                return err;
        }

        vol->dev.release = vol_release;
        vol->dev.parent = &ubi->dev;
        vol->dev.devt = dev;
        vol->dev.class = &ubi_class;
        vol->dev.groups = volume_dev_groups;
        dev_set_name(&vol->dev, "%s_%d", ubi->ubi_name, vol->vol_id);
        device_set_node(&vol->dev, find_volume_fwnode(vol));
        err = device_register(&vol->dev);
        if (err) {
                cdev_del(&vol->cdev);
                put_device(&vol->dev);
                return err;
        }

        self_check_volumes(ubi);
        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)
{
        dbg_gen("free volume %d", vol->vol_id);

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

/**
 * self_check_volume - check volume information.
 * @ubi: UBI device description object
 * @vol_id: volume ID
 *
 * Returns zero if volume is all right and a negative error code if not.
 */
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(ubi, "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(ubi, "negative values");
                goto fail;
        }
        if (vol->alignment > ubi->leb_size || vol->alignment == 0) {
                ubi_err(ubi, "bad alignment");
                goto fail;
        }

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

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

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

        if (vol->reserved_pebs > ubi->good_peb_count) {
                ubi_err(ubi, "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(ubi, "bad usable_leb_size, has to be %lld", n);
                goto fail;
        }

        if (vol->name_len > UBI_VOL_NAME_MAX) {
                ubi_err(ubi, "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(ubi, "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(ubi, "corrupted dynamic volume");
                        goto fail;
                }
                if (vol->used_ebs != vol->reserved_pebs) {
                        ubi_err(ubi, "bad used_ebs");
                        goto fail;
                }
                if (vol->last_eb_bytes != vol->usable_leb_size) {
                        ubi_err(ubi, "bad last_eb_bytes");
                        goto fail;
                }
                if (vol->used_bytes != n) {
                        ubi_err(ubi, "bad used_bytes");
                        goto fail;
                }

                if (vol->skip_check) {
                        ubi_err(ubi, "bad skip_check");
                        goto fail;
                }
        } else {
                if (vol->used_ebs < 0 || vol->used_ebs > vol->reserved_pebs) {
                        ubi_err(ubi, "bad used_ebs");
                        goto fail;
                }
                if (vol->last_eb_bytes < 0 ||
                    vol->last_eb_bytes > vol->usable_leb_size) {
                        ubi_err(ubi, "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(ubi, "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(ubi, "volume info is different");
                goto fail;
        }

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

fail:
        ubi_err(ubi, "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;
}

/**
 * self_check_volumes - check information about all volumes.
 * @ubi: UBI device description object
 *
 * Returns zero if volumes are all right and a negative error code if not.
 */
static int self_check_volumes(struct ubi_device *ubi)
{
        int i, err = 0;

        if (!ubi_dbg_chk_gen(ubi))
                return 0;

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

        return err;
}