source: mainline/uspace/lib/ext4/libext4_superblock.c@ 111d2d6

/*
 * Copyright (c) 2012 Frantisek Princ
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libext4
 * @{
 */

/**
 * @file  libext4_superblock.c
 * @brief Ext4 superblock operations.
 */

#include <byteorder.h>
#include <errno.h>
#include <block.h>
#include <malloc.h>
#include "libext4.h"

/** Get number of i-nodes in the whole filesystem.
 *
 * @param sb Superblock
 *
 * @return Number of i-nodes
 *
 */
uint32_t ext4_superblock_get_inodes_count(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->inodes_count);
}

/** Set number of i-nodes in the whole filesystem.
 *
 * @param sb    Superblock
 * @param count Number of i-nodes
 *
 */
void ext4_superblock_set_inodes_count(ext4_superblock_t *sb, uint32_t count)
{
        sb->inodes_count = host2uint32_t_le(count);
}

/** Get number of data blocks in the whole filesystem.
 *
 * @param sb Superblock
 *
 * @return Number of data blocks
 *
 */
uint64_t ext4_superblock_get_blocks_count(ext4_superblock_t *sb)
{
        return ((uint64_t) uint32_t_le2host(sb->blocks_count_hi) << 32) |
            uint32_t_le2host(sb->blocks_count_lo);
}

/** Set number of data blocks in the whole filesystem.
 *
 * @param sb    Superblock
 * @param count Number of data blocks
 *
 */
void ext4_superblock_set_blocks_count(ext4_superblock_t *sb, uint64_t count)
{
        sb->blocks_count_lo = host2uint32_t_le((count << 32) >> 32);
        sb->blocks_count_hi = host2uint32_t_le(count >> 32);
}

/** Get number of reserved data blocks in the whole filesystem.
 *
 * @param sb Superblock
 *
 * @return Number of reserved data blocks
 *
 */
uint64_t ext4_superblock_get_reserved_blocks_count(ext4_superblock_t *sb)
{
        return ((uint64_t)
            uint32_t_le2host(sb->reserved_blocks_count_hi) << 32) |
            uint32_t_le2host(sb->reserved_blocks_count_lo);
}

/** Set number of reserved data blocks in the whole filesystem.
 *
 * @param sb    Superblock
 * @param count Number of reserved data blocks
 *
 */
void ext4_superblock_set_reserved_blocks_count(ext4_superblock_t *sb,
    uint64_t count)
{
        sb->reserved_blocks_count_lo = host2uint32_t_le((count << 32) >> 32);
        sb->reserved_blocks_count_hi = host2uint32_t_le(count >> 32);
}

/** Get number of free data blocks in the whole filesystem.
 *
 * @param sb Superblock
 *
 * @return Number of free data blocks
 *
 */
uint64_t ext4_superblock_get_free_blocks_count(ext4_superblock_t *sb)
{
        return ((uint64_t)
            uint32_t_le2host(sb->free_blocks_count_hi) << 32) |
            uint32_t_le2host(sb->free_blocks_count_lo);
}

/** Set number of free data blocks in the whole filesystem.
 *
 * @param sb    Superblock
 * @param count Number of free data blocks
 *
 */
void ext4_superblock_set_free_blocks_count(ext4_superblock_t *sb,
    uint64_t count)
{
        sb->free_blocks_count_lo = host2uint32_t_le((count << 32) >> 32);
        sb->free_blocks_count_hi = host2uint32_t_le(count >> 32);
}

/** Get number of free i-nodes in the whole filesystem.
 *
 * @param sb Superblock
 *
 * @return Number of free i-nodes
 *
 */
uint32_t ext4_superblock_get_free_inodes_count(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->free_inodes_count);
}

/** Set number of free i-nodes in the whole filesystem.
 *
 * @param sb    Superblock
 * @param count Number of free i-nodes
 *
 */
void ext4_superblock_set_free_inodes_count(ext4_superblock_t *sb,
    uint32_t count)
{
        sb->free_inodes_count = host2uint32_t_le(count);
}

/** Get index of first data block (block where the superblock is located)
 *
 * @param sb Superblock
 *
 * @return Index of the first data block
 *
 */
uint32_t ext4_superblock_get_first_data_block(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->first_data_block);
}

/** Set index of first data block (block where the superblock is located)
 *
 * @param sb    Superblock
 * @param first Index of the first data block
 *
 */
void ext4_superblock_set_first_data_block(ext4_superblock_t *sb,
    uint32_t first)
{
        sb->first_data_block = host2uint32_t_le(first);
}

/** Get logarithmic block size (1024 << size == block_size)
 *
 * @param sb Superblock
 *
 * @return Logarithmic block size
 *
 */
uint32_t ext4_superblock_get_log_block_size(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->log_block_size);
}

/** Set logarithmic block size (1024 << size == block_size)
 *
 * @param sb Superblock
 *
 * @return Logarithmic block size
 *
 */
void ext4_superblock_set_log_block_size(ext4_superblock_t *sb,
    uint32_t log_size)
{
        sb->log_block_size = host2uint32_t_le(log_size);
}

/** Get size of data block (in bytes).
 *
 * @param sb Superblock
 *
 * @return Size of data block
 *
 */
uint32_t ext4_superblock_get_block_size(ext4_superblock_t *sb)
{
        return 1024 << ext4_superblock_get_log_block_size(sb);
}

/** Set size of data block (in bytes).
 *
 * @param sb   Superblock
 * @param size Size of data block (must be power of 2, at least 1024)
 *
 */
void ext4_superblock_set_block_size(ext4_superblock_t *sb, uint32_t size)
{
        uint32_t log = 0;
        uint32_t tmp = size / EXT4_MIN_BLOCK_SIZE;
        
        tmp >>= 1;
        while (tmp) {
                log++;
                tmp >>= 1;
        }
        
        ext4_superblock_set_log_block_size(sb, log);
}

/** Get logarithmic fragment size (1024 << size)
 *
 * @param sb Superblock
 *
 * @return Logarithmic fragment size
 *
 */
uint32_t ext4_superblock_get_log_frag_size(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->log_frag_size);
}

/** Set logarithmic fragment size (1024 << size)
 *
 * @param sb        Superblock
 * @param frag_size Logarithmic fragment size
 *
 */
void ext4_superblock_set_log_frag_size(ext4_superblock_t *sb,
    uint32_t frag_size)
{
        sb->log_frag_size = host2uint32_t_le(frag_size);
}

/** Get size of fragment (in bytes).
 *
 * @param sb Superblock
 *
 * @return Size of fragment
 *
 */
uint32_t ext4_superblock_get_frag_size(ext4_superblock_t *sb)
{
        return 1024 << ext4_superblock_get_log_frag_size(sb);
}

/** Set size of fragment (in bytes).
 *
 * @param sb   Superblock
 * @param size Size of fragment (must be power of 2, at least 1024)
 *
 */
void ext4_superblock_set_frag_size(ext4_superblock_t *sb, uint32_t size)
{
        uint32_t log = 0;
        uint32_t tmp = size / EXT4_MIN_BLOCK_SIZE;
        
        tmp >>= 1;
        while (tmp) {
                log++;
                tmp >>= 1;
        }
        
        ext4_superblock_set_log_frag_size(sb, log);
}

/** Get number of data blocks per block group (except last BG)
 *
 * @param sb Superblock
 *
 * @return Data blocks per block group
 *
 */
uint32_t ext4_superblock_get_blocks_per_group(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->blocks_per_group);
}

/** Set number of data blocks per block group (except last BG)
 *
 * @param sb     Superblock
 * @param blocks Data blocks per block group
 *
 */
void ext4_superblock_set_blocks_per_group(ext4_superblock_t *sb,
    uint32_t blocks)
{
        sb->blocks_per_group = host2uint32_t_le(blocks);
}

/** Get number of fragments per block group (except last BG)
 *
 * @param sb Superblock
 *
 * @return Fragments per block group
 *
 */
uint32_t ext4_superblock_get_frags_per_group(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->frags_per_group);
}

/** Set number of fragment per block group (except last BG)
 *
 * @param sb    Superblock
 * @param frags Fragments per block group
 */
void ext4_superblock_set_frags_per_group(ext4_superblock_t *sb, uint32_t frags)
{
        sb->frags_per_group = host2uint32_t_le(frags);
}

/** Get number of i-nodes per block group (except last BG)
 *
 * @param sb Superblock
 *
 * @return I-nodes per block group
 *
 */
uint32_t ext4_superblock_get_inodes_per_group(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->inodes_per_group);
}

/** Set number of i-nodes per block group (except last BG)
 *
 * @param sb     Superblock
 * @param inodes I-nodes per block group
 *
 */
void ext4_superblock_set_inodes_per_group(ext4_superblock_t *sb,
    uint32_t inodes)
{
        sb->inodes_per_group = host2uint32_t_le(inodes);
}

/** Get time when filesystem was mounted (POSIX time).
 *
 * @param sb Superblock
 *
 * @return Mount time
 *
 */
uint32_t ext4_superblock_get_mount_time(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->mount_time);
}

/** Set time when filesystem was mounted (POSIX time).
 *
 * @param sb   Superblock
 * @param time Mount time
 *
 */
void ext4_superblock_set_mount_time(ext4_superblock_t *sb, uint32_t time)
{
        sb->mount_time = host2uint32_t_le(time);
}

/** Get time when filesystem was last accesed by write operation (POSIX time).
 *
 * @param sb Superblock
 *
 * @return Write time
 *
 */
uint32_t ext4_superblock_get_write_time(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->write_time);
}

/** Set time when filesystem was last accesed by write operation (POSIX time).
 *
 * @param sb   Superblock
 * @param time Write time
 *
 */
void ext4_superblock_set_write_time(ext4_superblock_t *sb, uint32_t time)
{
        sb->write_time = host2uint32_t_le(time);
}

/** Get number of mount from last filesystem check.
 *
 * @param sb Superblock
 *
 * @return Number of mounts
 *
 */
uint16_t ext4_superblock_get_mount_count(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->mount_count);
}

/** Set number of mount from last filesystem check.
 *
 * @param sb    Superblock
 * @param count Number of mounts
 *
 */
void ext4_superblock_set_mount_count(ext4_superblock_t *sb, uint16_t count)
{
        sb->mount_count = host2uint16_t_le(count);
}

/** Get maximum number of mount from last filesystem check.
 *
 * @param sb Superblock
 *
 * @return Maximum number of mounts
 *
 */
uint16_t ext4_superblock_get_max_mount_count(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->max_mount_count);
}

/** Set maximum number of mount from last filesystem check.
 *
 * @param sb    Superblock
 * @param count Maximum number of mounts
 *
 */
void ext4_superblock_set_max_mount_count(ext4_superblock_t *sb, uint16_t count)
{
        sb->max_mount_count = host2uint16_t_le(count);
}

/** Get superblock magic value.
 *
 * @param sb Superblock
 *
 * @return Magic value
 *
 */
uint16_t ext4_superblock_get_magic(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->magic);
}

/** Set superblock magic value.
 *
 * @param sb    Superblock
 * @param magic Magic value
 *
 */
void ext4_superblock_set_magic(ext4_superblock_t *sb, uint16_t magic)
{
        sb->magic = host2uint16_t_le(magic);
}

/** Get filesystem state.
 *
 * @param sb Superblock
 *
 * @return Filesystem state
 *
 */
uint16_t ext4_superblock_get_state(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->state);
}

/** Set filesystem state.
 *
 * @param sb    Superblock
 * @param state Filesystem state
 *
 */
void ext4_superblock_set_state(ext4_superblock_t *sb, uint16_t state)
{
        sb->state = host2uint16_t_le(state);
}

/** Get behavior code when errors detected.
 *
 * @param sb Superblock
 *
 * @return Behavior code
 *
 */
uint16_t ext4_superblock_get_errors(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->errors);
}

/** Set behavior code when errors detected.
 *
 * @param sb     Superblock
 * @param errors Behavior code
 *
 */
void ext4_superblock_set_errors(ext4_superblock_t *sb, uint16_t errors)
{
        sb->errors = host2uint16_t_le(errors);
}

/** Get minor revision level of the filesystem.
 *
 * @param sb Superblock
 *
 * @return Minor revision level
 *
 */
uint16_t ext4_superblock_get_minor_rev_level(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->minor_rev_level);
}

/** Set minor revision level of the filesystem.
 *
 * @param sb    Superblock
 * @param level Minor revision level
 *
 */
void ext4_superblock_set_minor_rev_level(ext4_superblock_t *sb, uint16_t level)
{
        sb->minor_rev_level = host2uint16_t_le(level);
}

/** Get time of the last filesystem check.
 *
 * @param sb Superblock
 *
 * @return Time of the last check (POSIX)
 *
 */
uint32_t ext4_superblock_get_last_check_time(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->last_check_time);
}

/** Set time of the last filesystem check.
 *
 * @param sb   Superblock
 * @param time Time of the last check (POSIX)
 *
 */
void ext4_superblock_set_last_check_time(ext4_superblock_t *sb, uint32_t time)
{
        sb->state = host2uint32_t_le(time);
}

/** Get maximum time interval between two filesystem checks.
 *
 * @param sb Superblock
 *
 * @return Time interval between two check (POSIX)
 *
 */
uint32_t ext4_superblock_get_check_interval(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->check_interval);
}

/** Set maximum time interval between two filesystem checks.
 *
 * @param sb       Superblock
 * @param interval Time interval between two check (POSIX)
 *
 */
void ext4_superblock_set_check_interval(ext4_superblock_t *sb, uint32_t interval)
{
        sb->check_interval = host2uint32_t_le(interval);
}

/** Get operation system identifier, on which the filesystem was created.
 *
 * @param sb Superblock
 *
 * @return Operation system identifier
 *
 */
uint32_t ext4_superblock_get_creator_os(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->creator_os);
}

/** Set operation system identifier, on which the filesystem was created.
 *
 * @param sb Superblock
 * @param os Operation system identifier
 *
 */
void ext4_superblock_set_creator_os(ext4_superblock_t *sb, uint32_t os)
{
        sb->creator_os = host2uint32_t_le(os);
}

/** Get revision level of the filesystem.
 *
 * @param sb Superblock
 *
 * @return Revision level
 *
 */
uint32_t ext4_superblock_get_rev_level(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->rev_level);
}

/** Set revision level of the filesystem.
 *
 * @param sb    Superblock
 * @param level Revision level
 *
 */
void ext4_superblock_set_rev_level(ext4_superblock_t *sb, uint32_t level)
{
        sb->rev_level = host2uint32_t_le(level);
}

/** Get default user id for reserved blocks.
 *
 * @param sb Superblock
 *
 * @return Default user id for reserved blocks.
 *
 */
uint16_t ext4_superblock_get_def_resuid(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->def_resuid);
}

/** Set default user id for reserved blocks.
 *
 * @param sb  Superblock
 * @param uid Default user id for reserved blocks.
 *
 */
void ext4_superblock_set_def_resuid(ext4_superblock_t *sb, uint16_t uid)
{
        sb->def_resuid = host2uint16_t_le(uid);
}

/** Get default group id for reserved blocks.
 *
 * @param sb Superblock
 *
 * @return Default group id for reserved blocks.
 *
 */
uint16_t ext4_superblock_get_def_resgid(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->def_resgid);
}

/** Set default group id for reserved blocks.
 *
 * @param sb  Superblock
 * @param gid Default group id for reserved blocks.
 *
 */
void ext4_superblock_set_def_resgid(ext4_superblock_t *sb, uint16_t gid)
{
        sb->def_resgid = host2uint16_t_le(gid);
}

/** Get index of the first i-node, which can be used for allocation.
 *
 * @param sb Superblock
 *
 * @return I-node index
 *
 */
uint32_t ext4_superblock_get_first_inode(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->first_inode);
}

/** Set index of the first i-node, which can be used for allocation.
 *
 * @param sb          Superblock
 * @param first_inode I-node index
 *
 */
void ext4_superblock_set_first_inode(ext4_superblock_t *sb,
    uint32_t first_inode)
{
        sb->first_inode = host2uint32_t_le(first_inode);
}

/** Get size of i-node structure.
 *
 * For the oldest revision return constant number.
 *
 * @param sb Superblock
 *
 * @return Size of i-node structure
 *
 */
uint16_t ext4_superblock_get_inode_size(ext4_superblock_t *sb)
{
        if (ext4_superblock_get_rev_level(sb) == 0)
                return EXT4_REV0_INODE_SIZE;
        
        return uint16_t_le2host(sb->inode_size);
}

/** Set size of i-node structure.
 *
 * @param sb   Superblock
 * @param size Size of i-node structure
 *
 */
void ext4_superblock_set_inode_size(ext4_superblock_t *sb, uint16_t size)
{
        sb->inode_size = host2uint16_t_le(size);
}

/** Get index of block group, where superblock copy is located.
 *
 * @param sb Superblock
 *
 * @return Block group index
 *
 */
uint16_t ext4_superblock_get_block_group_index(ext4_superblock_t *sb)
{
        return uint16_t_le2host(sb->block_group_index);
}

/** Set index of block group, where superblock copy is located.
 *
 * @param sb   Superblock
 * @param bgid Block group index
 *
 */
void ext4_superblock_set_block_group_index(ext4_superblock_t *sb, uint16_t bgid)
{
        sb->block_group_index = host2uint16_t_le(bgid);
}

/** Get compatible features supported by the filesystem.
 *
 * @param sb Superblock
 *
 * @return Compatible features bitmap
 *
 */
uint32_t ext4_superblock_get_features_compatible(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->features_compatible);
}

/** Set compatible features supported by the filesystem.
 *
 * @param sb       Superblock
 * @param features Compatible features bitmap
 *
 */
void ext4_superblock_set_features_compatible(ext4_superblock_t *sb,
    uint32_t features)
{
        sb->features_compatible = host2uint32_t_le(features);
}

/** Get incompatible features supported by the filesystem.
 *
 * @param sb Superblock
 *
 * @return Incompatible features bitmap
 *
 */
uint32_t ext4_superblock_get_features_incompatible(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->features_incompatible);
}

/** Set incompatible features supported by the filesystem.
 *
 * @param sb       Superblock
 * @param features Incompatible features bitmap
 *
 */
void ext4_superblock_set_features_incompatible(ext4_superblock_t *sb,
    uint32_t features)
{
        sb->features_incompatible = host2uint32_t_le(features);
}

/** Get compatible features supported by the filesystem.
 *
 * @param sb Superblock
 *
 * @return Read-only compatible features bitmap
 *
 */
uint32_t ext4_superblock_get_features_read_only(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->features_read_only);
}

/** Set compatible features supported by the filesystem.
 *
 * @param sb      Superblock
 * @param feature Read-only compatible features bitmap
 *
 */
void ext4_superblock_set_features_read_only(ext4_superblock_t *sb,
    uint32_t features)
{
        sb->features_read_only = host2uint32_t_le(features);
}

/** Get UUID of the filesystem.
 *
 * @param sb superblock
 *
 * @return Pointer to UUID array
 *
 */
const uint8_t *ext4_superblock_get_uuid(ext4_superblock_t *sb)
{
        return sb->uuid;
}

/** Set UUID of the filesystem.
 *
 * @param sb   Superblock
 * @param uuid Pointer to UUID array
 *
 */
void ext4_superblock_set_uuid(ext4_superblock_t *sb, const uint8_t *uuid)
{
        memcpy(sb->uuid, uuid, sizeof(sb->uuid));
}

/** Get name of the filesystem volume.
 *
 * @param sb Superblock
 *
 * @return Name of the volume
 *
 */
const char *ext4_superblock_get_volume_name(ext4_superblock_t *sb)
{
        return sb->volume_name;
}

/** Set name of the filesystem volume.
 *
 * @param sb   Superblock
 * @param name New name of the volume
 */
void ext4_superblock_set_volume_name(ext4_superblock_t *sb, const char *name)
{
        memcpy(sb->volume_name, name, sizeof(sb->volume_name));
}

/** Get name of the directory, where this filesystem was mounted at last.
 *
 * @param sb Superblock
 *
 * @return Directory name
 *
 */
const char *ext4_superblock_get_last_mounted(ext4_superblock_t *sb)
{
        return sb->last_mounted;
}

/** Set name of the directory, where this filesystem was mounted at last.
 *
 * @param sb   Superblock
 * @param last Directory name
 *
 */
void ext4_superblock_set_last_mounted(ext4_superblock_t *sb, const char *last)
{
        memcpy(sb->last_mounted, last, sizeof(sb->last_mounted));
}

/** Get last orphaned i-node index.
 *
 * Orphans are stored in linked list.
 *
 * @param sb Superblock
 *
 * @return Last orphaned i-node index
 *
 */
uint32_t ext4_superblock_get_last_orphan(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->last_orphan);
}

/** Set last orphaned i-node index.
 *
 * Orphans are stored in linked list.
 *
 * @param sb          Superblock
 * @param last_orphan Last orphaned i-node index
 *
 */
void ext4_superblock_set_last_orphan(ext4_superblock_t *sb,
    uint32_t last_orphan)
{
        sb->last_orphan = host2uint32_t_le(last_orphan);
}

/** Get hash seed for directory index hash function.
 *
 * @param sb Superblock
 *
 * @return Hash seed pointer
 *
 */
const uint32_t *ext4_superblock_get_hash_seed(ext4_superblock_t *sb)
{
        return sb->hash_seed;
}

/** Set hash seed for directory index hash function.
 *
 * @param sb   Superblock
 * @param seed Hash seed pointer
 *
 */
void ext4_superblock_set_hash_seed(ext4_superblock_t *sb, const uint32_t *seed)
{
        memcpy(sb->hash_seed, seed, sizeof(sb->hash_seed));
}

/** Get default version of the hash algorithm version for directory index.
 *
 * @param sb Superblock
 *
 * @return Default hash version
 *
 */
uint8_t ext4_superblock_get_default_hash_version(ext4_superblock_t *sb)
{
        return sb->default_hash_version;
}

/** Set default version of the hash algorithm version for directory index.
 *
 * @param sb      Superblock
 * @param version Default hash version
 *
 */
void ext4_superblock_set_default_hash_version(ext4_superblock_t *sb,
    uint8_t version)
{
        sb->default_hash_version = version;
}

/** Get size of block group descriptor structure.
 *
 * Output value is checked for minimal size.
 *
 * @param sb Superblock
 *
 * @return Size of block group descriptor
 *
 */
uint16_t ext4_superblock_get_desc_size(ext4_superblock_t *sb)
{
        uint16_t size = uint16_t_le2host(sb->desc_size);
        
        if (size < EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)
                size = EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE;
        
        return size;
}

/** Set size of block group descriptor structure.
 *
 * Input value is checked for minimal size.
 *
 * @param sb   Superblock
 * @param size Size of block group descriptor
 *
 */
void ext4_superblock_set_desc_size(ext4_superblock_t *sb, uint16_t size)
{
        if (size < EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)
                sb->desc_size =
                    host2uint16_t_le(EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE);
        
        sb->desc_size = host2uint16_t_le(size);
}

/** Get superblock flags.
 *
 * @param sb Superblock
 *
 * @return Flags from the superblock
 *
 */
uint32_t ext4_superblock_get_flags(ext4_superblock_t *sb)
{
        return uint32_t_le2host(sb->flags);
}

/** Set superblock flags.
 *
 * @param sb    Superblock
 * @param flags Flags for the superblock
 *
 */
void ext4_superblock_set_flags(ext4_superblock_t *sb, uint32_t flags)
{
        sb->flags = host2uint32_t_le(flags);
}

/*
 * More complex superblock operations
 */

/** Check if superblock has specified flag.
 *
 * @param sb   Superblock
 * @param flag Flag to be checked
 *
 * @return True, if superblock has the flag
 *
 */
bool ext4_superblock_has_flag(ext4_superblock_t *sb, uint32_t flag)
{
        if (ext4_superblock_get_flags(sb) & flag)
                return true;
        
        return false;
}

/** Check if filesystem supports compatible feature.
 *
 * @param sb      Superblock
 * @param feature Feature to be checked
 *
 * @return True, if filesystem supports the feature
 *
 */
bool ext4_superblock_has_feature_compatible(ext4_superblock_t *sb,
    uint32_t feature)
{
        if (ext4_superblock_get_features_compatible(sb) & feature)
                return true;
        
        return false;
}

/** Check if filesystem supports incompatible feature.
 *
 * @param sb      Superblock
 * @param feature Feature to be checked
 *
 * @return True, if filesystem supports the feature
 *
 */
bool ext4_superblock_has_feature_incompatible(ext4_superblock_t *sb,
    uint32_t feature)
{
        if (ext4_superblock_get_features_incompatible(sb) & feature)
                return true;
        
        return false;
}

/** Check if filesystem supports read-only compatible feature.
 *
 * @param sb      Superblock
 * @param feature Feature to be checked
 *
 * @return True, if filesystem supports the feature
 *
 */
bool ext4_superblock_has_feature_read_only(ext4_superblock_t *sb,
    uint32_t feature)
{
        if (ext4_superblock_get_features_read_only(sb) & feature)
                return true;
        
        return false;
}

/** Read superblock directly from block device.
 *
 * @param service_id Block device identifier
 * @param sb         Output pointer to memory structure
 *
 * @return Eerror code.
 *
 */
int ext4_superblock_read_direct(service_id_t service_id, ext4_superblock_t **sb)
{
        /* Allocated memory for superblock structure */
        void *data = malloc(EXT4_SUPERBLOCK_SIZE);
        if (data == NULL)
                return ENOMEM;
        
        /* Read data from block device */
        int rc = block_read_bytes_direct(service_id, EXT4_SUPERBLOCK_OFFSET,
            EXT4_SUPERBLOCK_SIZE, data);
        
        if (rc != EOK) {
                free(data);
                return rc;
        }
        
        /* Set output value */
        (*sb) = data;
        
        return EOK;
}

/** Write superblock structure directly to block device.
 *
 * @param service_id Block device identifier
 * @param sb         Superblock to be written
 *
 * @return Error code
 *
 */
int ext4_superblock_write_direct(service_id_t service_id, ext4_superblock_t *sb)
{
        /* Load physical block size from block device */
        size_t phys_block_size;
        int rc = block_get_bsize(service_id, &phys_block_size);
        if (rc != EOK)
                return rc;
        
        /* Compute address of the first block */
        uint64_t first_block = EXT4_SUPERBLOCK_OFFSET / phys_block_size;
        
        /* Compute number of block to write */
        size_t block_count = EXT4_SUPERBLOCK_SIZE / phys_block_size;
        
        /* Check alignment */
        if (EXT4_SUPERBLOCK_SIZE % phys_block_size)
                block_count++;
        
        /* Write data */
        return block_write_direct(service_id, first_block, block_count, sb);
}

/** Check sanity of the superblock.
 *
 * This check is performed at mount time.
 * Checks are described by one-line comments in the code.
 *
 * @param sb Superblock to check
 *
 * @return Error code
 *
 */
int ext4_superblock_check_sanity(ext4_superblock_t *sb)
{
        if (ext4_superblock_get_magic(sb) != EXT4_SUPERBLOCK_MAGIC)
                return ENOTSUP;
        
        if (ext4_superblock_get_inodes_count(sb) == 0)
                return ENOTSUP;
        
        if (ext4_superblock_get_blocks_count(sb) == 0)
                return ENOTSUP;
        
        if (ext4_superblock_get_blocks_per_group(sb) == 0)
                return ENOTSUP;
        
        if (ext4_superblock_get_inodes_per_group(sb) == 0)
                return ENOTSUP;
        
        if (ext4_superblock_get_inode_size(sb) < 128)
                return ENOTSUP;
        
        if (ext4_superblock_get_first_inode(sb) < 11)
                return ENOTSUP;
        
        if (ext4_superblock_get_desc_size(sb) <
            EXT4_MIN_BLOCK_GROUP_DESCRIPTOR_SIZE)
                return ENOTSUP;
        
        if (ext4_superblock_get_desc_size(sb) >
            EXT4_MAX_BLOCK_GROUP_DESCRIPTOR_SIZE)
                return ENOTSUP;
        
        return EOK;
}

/** Compute number of block groups in the filesystem.
 *
 * @param sb Superblock
 *
 * @return Number of block groups
 *
 */
uint32_t ext4_superblock_get_block_group_count(ext4_superblock_t *sb)
{
        uint64_t blocks_count = ext4_superblock_get_blocks_count(sb);
        uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb);
        
        uint32_t block_groups_count = blocks_count / blocks_per_group;
        
        if (blocks_count % blocks_per_group)
                block_groups_count++;
        
        return block_groups_count;
}

/** Compute number of blocks in specified block group.
 *
 * @param sb   Superblock
 * @param bgid Block group index
 *
 * @return Number of blocks
 *
 */
uint32_t ext4_superblock_get_blocks_in_group(ext4_superblock_t *sb, uint32_t bgid)
{
        uint32_t block_group_count =
            ext4_superblock_get_block_group_count(sb);
        uint32_t blocks_per_group =
            ext4_superblock_get_blocks_per_group(sb);
        uint64_t total_blocks =
            ext4_superblock_get_blocks_count(sb);
        
        if (bgid < block_group_count - 1)
                return blocks_per_group;
        else
                return (total_blocks - ((block_group_count - 1) * blocks_per_group));
}

/** Compute number of i-nodes in specified block group.
 *
 * @param sb   Superblock
 * @param bgid Block group index
 *
 * @return Number of i-nodes
 *
 */
uint32_t ext4_superblock_get_inodes_in_group(ext4_superblock_t *sb, uint32_t bgid)
{
        uint32_t block_group_count =
            ext4_superblock_get_block_group_count(sb);
        uint32_t inodes_per_group =
            ext4_superblock_get_inodes_per_group(sb);
        uint32_t total_inodes =
            ext4_superblock_get_inodes_count(sb);
        
        if (bgid < block_group_count - 1)
                return inodes_per_group;
        else
                return (total_inodes - ((block_group_count - 1) * inodes_per_group));
}

/**
 * @}
 */