// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2011 - 2012 Samsung Electronics
 * EXT4 filesystem implementation in Uboot by
 * Uma Shankar <uma.shankar@samsung.com>
 * Manjunatha C Achar <a.manjunatha@samsung.com>
 *
 * ext4ls and ext4load : Based on ext2 ls load support in Uboot.
 *
 * (C) Copyright 2004
 * esd gmbh <www.esd-electronics.com>
 * Reinhard Arlt <reinhard.arlt@esd-electronics.com>
 *
 * based on code from grub2 fs/ext2.c and fs/fshelp.c by
 * GRUB  --  GRand Unified Bootloader
 * Copyright (C) 2003, 2004  Free Software Foundation, Inc.
 *
 * ext4write : Based on generic ext4 protocol.
 */

#include <common.h>
#include <ext_common.h>
#include <ext4fs.h>
#include <malloc.h>
#include <memalign.h>
#include <stddef.h>
#include <linux/stat.h>
#include <linux/time.h>
#include <asm/byteorder.h>
#include "ext4_common.h"

struct ext2_data *ext4fs_root;
struct ext2fs_node *ext4fs_file;
__le32 *ext4fs_indir1_block;
int ext4fs_indir1_size;
int ext4fs_indir1_blkno = -1;
__le32 *ext4fs_indir2_block;
int ext4fs_indir2_size;
int ext4fs_indir2_blkno = -1;

__le32 *ext4fs_indir3_block;
int ext4fs_indir3_size;
int ext4fs_indir3_blkno = -1;
struct ext2_inode *g_parent_inode;
static int symlinknest;

#if defined(CONFIG_EXT4_WRITE)
struct ext2_block_group *ext4fs_get_group_descriptor
        (const struct ext_filesystem *fs, uint32_t bg_idx)
{
        return (struct ext2_block_group *)(fs->gdtable + (bg_idx * fs->gdsize));
}

static inline void ext4fs_sb_free_inodes_dec(struct ext2_sblock *sb)
{
        sb->free_inodes = cpu_to_le32(le32_to_cpu(sb->free_inodes) - 1);
}

static inline void ext4fs_sb_free_blocks_dec(struct ext2_sblock *sb)
{
        uint64_t free_blocks = le32_to_cpu(sb->free_blocks);
        free_blocks += (uint64_t)le32_to_cpu(sb->free_blocks_high) << 32;
        free_blocks--;

        sb->free_blocks = cpu_to_le32(free_blocks & 0xffffffff);
        sb->free_blocks_high = cpu_to_le16(free_blocks >> 32);
}

static inline void ext4fs_bg_free_inodes_dec
        (struct ext2_block_group *bg, const struct ext_filesystem *fs)
{
        uint32_t free_inodes = le16_to_cpu(bg->free_inodes);
        if (fs->gdsize == 64)
                free_inodes += le16_to_cpu(bg->free_inodes_high) << 16;
        free_inodes--;

        bg->free_inodes = cpu_to_le16(free_inodes & 0xffff);
        if (fs->gdsize == 64)
                bg->free_inodes_high = cpu_to_le16(free_inodes >> 16);
}

static inline void ext4fs_bg_free_blocks_dec
        (struct ext2_block_group *bg, const struct ext_filesystem *fs)
{
        uint32_t free_blocks = le16_to_cpu(bg->free_blocks);
        if (fs->gdsize == 64)
                free_blocks += le16_to_cpu(bg->free_blocks_high) << 16;
        free_blocks--;

        bg->free_blocks = cpu_to_le16(free_blocks & 0xffff);
        if (fs->gdsize == 64)
                bg->free_blocks_high = cpu_to_le16(free_blocks >> 16);
}

static inline void ext4fs_bg_itable_unused_dec
        (struct ext2_block_group *bg, const struct ext_filesystem *fs)
{
        uint32_t free_inodes = le16_to_cpu(bg->bg_itable_unused);
        if (fs->gdsize == 64)
                free_inodes += le16_to_cpu(bg->bg_itable_unused_high) << 16;
        free_inodes--;

        bg->bg_itable_unused = cpu_to_le16(free_inodes & 0xffff);
        if (fs->gdsize == 64)
                bg->bg_itable_unused_high = cpu_to_le16(free_inodes >> 16);
}

uint64_t ext4fs_sb_get_free_blocks(const struct ext2_sblock *sb)
{
        uint64_t free_blocks = le32_to_cpu(sb->free_blocks);
        free_blocks += (uint64_t)le32_to_cpu(sb->free_blocks_high) << 32;
        return free_blocks;
}

void ext4fs_sb_set_free_blocks(struct ext2_sblock *sb, uint64_t free_blocks)
{
        sb->free_blocks = cpu_to_le32(free_blocks & 0xffffffff);
        sb->free_blocks_high = cpu_to_le16(free_blocks >> 32);
}

uint32_t ext4fs_bg_get_free_blocks(const struct ext2_block_group *bg,
                                   const struct ext_filesystem *fs)
{
        uint32_t free_blocks = le16_to_cpu(bg->free_blocks);
        if (fs->gdsize == 64)
                free_blocks += le16_to_cpu(bg->free_blocks_high) << 16;
        return free_blocks;
}

static inline
uint32_t ext4fs_bg_get_free_inodes(const struct ext2_block_group *bg,
                                   const struct ext_filesystem *fs)
{
        uint32_t free_inodes = le16_to_cpu(bg->free_inodes);
        if (fs->gdsize == 64)
                free_inodes += le16_to_cpu(bg->free_inodes_high) << 16;
        return free_inodes;
}

static inline uint16_t ext4fs_bg_get_flags(const struct ext2_block_group *bg)
{
        return le16_to_cpu(bg->bg_flags);
}

static inline void ext4fs_bg_set_flags(struct ext2_block_group *bg,
                                       uint16_t flags)
{
        bg->bg_flags = cpu_to_le16(flags);
}

/* Block number of the block bitmap */
uint64_t ext4fs_bg_get_block_id(const struct ext2_block_group *bg,
                                const struct ext_filesystem *fs)
{
        uint64_t block_nr = le32_to_cpu(bg->block_id);
        if (fs->gdsize == 64)
                block_nr += (uint64_t)le32_to_cpu(bg->block_id_high) << 32;
        return block_nr;
}

/* Block number of the inode bitmap */
uint64_t ext4fs_bg_get_inode_id(const struct ext2_block_group *bg,
                                const struct ext_filesystem *fs)
{
        uint64_t block_nr = le32_to_cpu(bg->inode_id);
        if (fs->gdsize == 64)
                block_nr += (uint64_t)le32_to_cpu(bg->inode_id_high) << 32;
        return block_nr;
}
#endif

/* Block number of the inode table */
uint64_t ext4fs_bg_get_inode_table_id(const struct ext2_block_group *bg,
                                      const struct ext_filesystem *fs)
{
        uint64_t block_nr = le32_to_cpu(bg->inode_table_id);
        if (fs->gdsize == 64)
                block_nr +=
                        (uint64_t)le32_to_cpu(bg->inode_table_id_high) << 32;
        return block_nr;
}

#if defined(CONFIG_EXT4_WRITE)
uint32_t ext4fs_div_roundup(uint32_t size, uint32_t n)
{
        uint32_t res = size / n;
        if (res * n != size)
                res++;

        return res;
}

void put_ext4(uint64_t off, void *buf, uint32_t size)
{
        uint64_t startblock;
        uint64_t remainder;
        unsigned char *temp_ptr = NULL;
        struct ext_filesystem *fs = get_fs();
        int log2blksz = fs->dev_desc->log2blksz;
        ALLOC_CACHE_ALIGN_BUFFER(unsigned char, sec_buf, fs->dev_desc->blksz);

        startblock = off >> log2blksz;
        startblock += part_offset;
        remainder = off & (uint64_t)(fs->dev_desc->blksz - 1);

        if (fs->dev_desc == NULL)
                return;

        if ((startblock + (size >> log2blksz)) >
            (part_offset + fs->total_sect)) {
                printf("part_offset is " LBAFU "\n", part_offset);
                printf("total_sector is %llu\n", fs->total_sect);
                printf("error: overflow occurs\n");
                return;
        }

        if (remainder) {
                blk_dread(fs->dev_desc, startblock, 1, sec_buf);
                temp_ptr = sec_buf;
                memcpy((temp_ptr + remainder), (unsigned char *)buf, size);
                blk_dwrite(fs->dev_desc, startblock, 1, sec_buf);
        } else {
                if (size >> log2blksz != 0) {
                        blk_dwrite(fs->dev_desc, startblock, size >> log2blksz,
                                   (unsigned long *)buf);
                } else {
                        blk_dread(fs->dev_desc, startblock, 1, sec_buf);
                        temp_ptr = sec_buf;
                        memcpy(temp_ptr, buf, size);
                        blk_dwrite(fs->dev_desc, startblock, 1,
                                   (unsigned long *)sec_buf);
                }
        }
}

static int _get_new_inode_no(unsigned char *buffer)
{
        struct ext_filesystem *fs = get_fs();
        unsigned char input;
        int operand, status;
        int count = 1;
        int j = 0;

        /* get the blocksize of the filesystem */
        unsigned char *ptr = buffer;
        while (*ptr == 255) {
                ptr++;
                count += 8;
                if (count > le32_to_cpu(ext4fs_root->sblock.inodes_per_group))
                        return -1;
        }

        for (j = 0; j < fs->blksz; j++) {
                input = *ptr;
                int i = 0;
                while (i <= 7) {
                        operand = 1 << i;
                        status = input & operand;
                        if (status) {
                                i++;
                                count++;
                        } else {
                                *ptr |= operand;
                                return count;
                        }
                }
                ptr = ptr + 1;
        }

        return -1;
}

static int _get_new_blk_no(unsigned char *buffer)
{
        int operand;
        int count = 0;
        int i;
        unsigned char *ptr = buffer;
        struct ext_filesystem *fs = get_fs();

        while (*ptr == 255) {
                ptr++;
                count += 8;
                if (count == (fs->blksz * 8))
                        return -1;
        }

        if (fs->blksz == 1024)
                count += 1;

        for (i = 0; i <= 7; i++) {
                operand = 1 << i;
                if (*ptr & operand) {
                        count++;
                } else {
                        *ptr |= operand;
                        return count;
                }
        }

        return -1;
}

int ext4fs_set_block_bmap(long int blockno, unsigned char *buffer, int index)
{
        int i, remainder, status;
        unsigned char *ptr = buffer;
        unsigned char operand;
        i = blockno / 8;
        remainder = blockno % 8;
        int blocksize = EXT2_BLOCK_SIZE(ext4fs_root);

        i = i - (index * blocksize);
        if (blocksize != 1024) {
                ptr = ptr + i;
                operand = 1 << remainder;
                status = *ptr & operand;
                if (status)
                        return -1;

                *ptr = *ptr | operand;
                return 0;
        } else {
                if (remainder == 0) {
                        ptr = ptr + i - 1;
                        operand = (1 << 7);
                } else {
                        ptr = ptr + i;
                        operand = (1 << (remainder - 1));
                }
                status = *ptr & operand;
                if (status)
                        return -1;

                *ptr = *ptr | operand;
                return 0;
        }
}

void ext4fs_reset_block_bmap(long int blockno, unsigned char *buffer, int index)
{
        int i, remainder, status;
        unsigned char *ptr = buffer;
        unsigned char operand;
        i = blockno / 8;
        remainder = blockno % 8;
        int blocksize = EXT2_BLOCK_SIZE(ext4fs_root);

        i = i - (index * blocksize);
        if (blocksize != 1024) {
                ptr = ptr + i;
                operand = (1 << remainder);
                status = *ptr & operand;
                if (status)
                        *ptr = *ptr & ~(operand);
        } else {
                if (remainder == 0) {
                        ptr = ptr + i - 1;
                        operand = (1 << 7);
                } else {
                        ptr = ptr + i;
                        operand = (1 << (remainder - 1));
                }
                status = *ptr & operand;
                if (status)
                        *ptr = *ptr & ~(operand);
        }
}

int ext4fs_set_inode_bmap(int inode_no, unsigned char *buffer, int index)
{
        int i, remainder, status;
        unsigned char *ptr = buffer;
        unsigned char operand;

        inode_no -= (index * le32_to_cpu(ext4fs_root->sblock.inodes_per_group));
        i = inode_no / 8;
        remainder = inode_no % 8;
        if (remainder == 0) {
                ptr = ptr + i - 1;
                operand = (1 << 7);
        } else {
                ptr = ptr + i;
                operand = (1 << (remainder - 1));
        }
        status = *ptr & operand;
        if (status)
                return -1;

        *ptr = *ptr | operand;

        return 0;
}

void ext4fs_reset_inode_bmap(int inode_no, unsigned char *buffer, int index)
{
        int i, remainder, status;
        unsigned char *ptr = buffer;
        unsigned char operand;

        inode_no -= (index * le32_to_cpu(ext4fs_root->sblock.inodes_per_group));
        i = inode_no / 8;
        remainder = inode_no % 8;
        if (remainder == 0) {
                ptr = ptr + i - 1;
                operand = (1 << 7);
        } else {
                ptr = ptr + i;
                operand = (1 << (remainder - 1));
        }
        status = *ptr & operand;
        if (status)
                *ptr = *ptr & ~(operand);
}

uint16_t ext4fs_checksum_update(uint32_t i)
{
        struct ext2_block_group *desc;
        struct ext_filesystem *fs = get_fs();
        uint16_t crc = 0;
        __le32 le32_i = cpu_to_le32(i);

        desc = ext4fs_get_group_descriptor(fs, i);
        if (le32_to_cpu(fs->sb->feature_ro_compat) & EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
                int offset = offsetof(struct ext2_block_group, bg_checksum);

                crc = ext2fs_crc16(~0, fs->sb->unique_id,
                                   sizeof(fs->sb->unique_id));
                crc = ext2fs_crc16(crc, &le32_i, sizeof(le32_i));
                crc = ext2fs_crc16(crc, desc, offset);
                offset += sizeof(desc->bg_checksum);    /* skip checksum */
                assert(offset == sizeof(*desc));
                if (offset < fs->gdsize) {
                        crc = ext2fs_crc16(crc, (__u8 *)desc + offset,
                                           fs->gdsize - offset);
                }
        }

        return crc;
}

static int check_void_in_dentry(struct ext2_dirent *dir, char *filename)
{
        int dentry_length;
        int sizeof_void_space;
        int new_entry_byte_reqd;
        short padding_factor = 0;

        if (dir->namelen % 4 != 0)
                padding_factor = 4 - (dir->namelen % 4);

        dentry_length = sizeof(struct ext2_dirent) +
                        dir->namelen + padding_factor;
        sizeof_void_space = le16_to_cpu(dir->direntlen) - dentry_length;
        if (sizeof_void_space == 0)
                return 0;

        padding_factor = 0;
        if (strlen(filename) % 4 != 0)
                padding_factor = 4 - (strlen(filename) % 4);

        new_entry_byte_reqd = strlen(filename) +
            sizeof(struct ext2_dirent) + padding_factor;
        if (sizeof_void_space >= new_entry_byte_reqd) {
                dir->direntlen = cpu_to_le16(dentry_length);
                return sizeof_void_space;
        }

        return 0;
}

int ext4fs_update_parent_dentry(char *filename, int file_type)
{
        unsigned int *zero_buffer = NULL;
        char *root_first_block_buffer = NULL;
        int blk_idx;
        long int first_block_no_of_root = 0;
        int totalbytes = 0;
        unsigned int new_entry_byte_reqd;
        int sizeof_void_space = 0;
        int templength = 0;
        int inodeno = -1;
        int status;
        struct ext_filesystem *fs = get_fs();
        /* directory entry */
        struct ext2_dirent *dir;
        char *temp_dir = NULL;
        uint32_t new_blk_no;
        uint32_t new_size;
        uint32_t new_blockcnt;
        uint32_t directory_blocks;

        zero_buffer = zalloc(fs->blksz);
        if (!zero_buffer) {
                printf("No Memory\n");
                return -1;
        }
        root_first_block_buffer = zalloc(fs->blksz);
        if (!root_first_block_buffer) {
                free(zero_buffer);
                printf("No Memory\n");
                return -1;
        }
        new_entry_byte_reqd = ROUND(strlen(filename) +
                                    sizeof(struct ext2_dirent), 4);
restart:
        directory_blocks = le32_to_cpu(g_parent_inode->size) >>
                LOG2_BLOCK_SIZE(ext4fs_root);
        blk_idx = directory_blocks - 1;

restart_read:
        /* read the block no allocated to a file */
        first_block_no_of_root = read_allocated_block(g_parent_inode, blk_idx);
        if (first_block_no_of_root <= 0)
                goto fail;

        status = ext4fs_devread((lbaint_t)first_block_no_of_root
                                * fs->sect_perblk,
                                0, fs->blksz, root_first_block_buffer);
        if (status == 0)
                goto fail;

        if (ext4fs_log_journal(root_first_block_buffer, first_block_no_of_root))
                goto fail;
        dir = (struct ext2_dirent *)root_first_block_buffer;
        totalbytes = 0;

        while (le16_to_cpu(dir->direntlen) > 0) {
                unsigned short used_len = ROUND(dir->namelen +
                    sizeof(struct ext2_dirent), 4);

                /* last entry of block */
                if (fs->blksz - totalbytes == le16_to_cpu(dir->direntlen)) {

                        /* check if new entry fits */
                        if ((used_len + new_entry_byte_reqd) <=
                            le16_to_cpu(dir->direntlen)) {
                                dir->direntlen = cpu_to_le16(used_len);
                                break;
                        } else {
                                if (blk_idx > 0) {
                                        printf("Block full, trying previous\n");
                                        blk_idx--;
                                        goto restart_read;
                                }
                                printf("All blocks full: Allocate new\n");

                                if (le32_to_cpu(g_parent_inode->flags) &
                                                EXT4_EXTENTS_FL) {
                                        printf("Directory uses extents\n");
                                        goto fail;
                                }
                                if (directory_blocks >= INDIRECT_BLOCKS) {
                                        printf("Directory exceeds limit\n");
                                        goto fail;
                                }
                                new_blk_no = ext4fs_get_new_blk_no();
                                if (new_blk_no == -1) {
                                        printf("no block left to assign\n");
                                        goto fail;
                                }
                                put_ext4((uint64_t)new_blk_no * fs->blksz, zero_buffer, fs->blksz);
                                g_parent_inode->b.blocks.
                                        dir_blocks[directory_blocks] =
                                        cpu_to_le32(new_blk_no);

                                new_size = le32_to_cpu(g_parent_inode->size);
                                new_size += fs->blksz;
                                g_parent_inode->size = cpu_to_le32(new_size);

                                new_blockcnt = le32_to_cpu(g_parent_inode->blockcnt);
                                new_blockcnt += fs->sect_perblk;
                                g_parent_inode->blockcnt = cpu_to_le32(new_blockcnt);

                                if (ext4fs_put_metadata
                                    (root_first_block_buffer,
                                     first_block_no_of_root))
                                        goto fail;
                                goto restart;
                        }
                }

                templength = le16_to_cpu(dir->direntlen);
                totalbytes = totalbytes + templength;
                sizeof_void_space = check_void_in_dentry(dir, filename);
                if (sizeof_void_space)
                        break;

                dir = (struct ext2_dirent *)((char *)dir + templength);
        }

        /* make a pointer ready for creating next directory entry */
        templength = le16_to_cpu(dir->direntlen);
        totalbytes = totalbytes + templength;
        dir = (struct ext2_dirent *)((char *)dir + templength);

        /* get the next available inode number */
        inodeno = ext4fs_get_new_inode_no();
        if (inodeno == -1) {
                printf("no inode left to assign\n");
                goto fail;
        }
        dir->inode = cpu_to_le32(inodeno);
        if (sizeof_void_space)
                dir->direntlen = cpu_to_le16(sizeof_void_space);
        else
                dir->direntlen = cpu_to_le16(fs->blksz - totalbytes);

        dir->namelen = strlen(filename);
        dir->filetype = FILETYPE_REG;   /* regular file */
        temp_dir = (char *)dir;
        temp_dir = temp_dir + sizeof(struct ext2_dirent);
        memcpy(temp_dir, filename, strlen(filename));

        /* update or write  the 1st block of root inode */
        if (ext4fs_put_metadata(root_first_block_buffer,
                                first_block_no_of_root))
                goto fail;

fail:
        free(zero_buffer);
        free(root_first_block_buffer);

        return inodeno;
}

static int search_dir(struct ext2_inode *parent_inode, char *dirname)
{
        int status;
        int inodeno = 0;
        int offset;
        int blk_idx;
        long int blknr;
        char *block_buffer = NULL;
        struct ext2_dirent *dir = NULL;
        struct ext_filesystem *fs = get_fs();
        uint32_t directory_blocks;
        char *direntname;

        directory_blocks = le32_to_cpu(parent_inode->size) >>
                LOG2_BLOCK_SIZE(ext4fs_root);

        block_buffer = zalloc(fs->blksz);
        if (!block_buffer)
                goto fail;

        /* get the block no allocated to a file */
        for (blk_idx = 0; blk_idx < directory_blocks; blk_idx++) {
                blknr = read_allocated_block(parent_inode, blk_idx);
                if (blknr <= 0)
                        goto fail;

                /* read the directory block */
                status = ext4fs_devread((lbaint_t)blknr * fs->sect_perblk,
                                        0, fs->blksz, (char *)block_buffer);
                if (status == 0)
                        goto fail;

                offset = 0;
                do {
                        if (offset & 3) {
                                printf("Badly aligned ext2_dirent\n");
                                break;
                        }

                        dir = (struct ext2_dirent *)(block_buffer + offset);
                        direntname = (char*)(dir) + sizeof(struct ext2_dirent);

                        int direntlen = le16_to_cpu(dir->direntlen);
                        if (direntlen < sizeof(struct ext2_dirent))
                                break;

                        if (dir->inode && (strlen(dirname) == dir->namelen) &&
                            (strncmp(dirname, direntname, dir->namelen) == 0)) {
                                inodeno = le32_to_cpu(dir->inode);
                                break;
                        }

                        offset += direntlen;

                } while (offset < fs->blksz);

                if (inodeno > 0) {
                        free(block_buffer);
                        return inodeno;
                }
        }

fail:
        free(block_buffer);

        return -1;
}

static int find_dir_depth(char *dirname)
{
        char *token = strtok(dirname, "/");
        int count = 0;
        while (token != NULL) {
                token = strtok(NULL, "/");
                count++;
        }
        return count + 1 + 1;
        /*
         * for example  for string /home/temp
         * depth=home(1)+temp(1)+1 extra for NULL;
         * so count is 4;
         */
}

static int parse_path(char **arr, char *dirname)
{
        char *token = strtok(dirname, "/");
        int i = 0;

        /* add root */
        arr[i] = zalloc(strlen("/") + 1);
        if (!arr[i])
                return -ENOMEM;
        memcpy(arr[i++], "/", strlen("/"));

        /* add each path entry after root */
        while (token != NULL) {
                arr[i] = zalloc(strlen(token) + 1);
                if (!arr[i])
                        return -ENOMEM;
                memcpy(arr[i++], token, strlen(token));
                token = strtok(NULL, "/");
        }
        arr[i] = NULL;

        return 0;
}

int ext4fs_iget(int inode_no, struct ext2_inode *inode)
{
        if (ext4fs_read_inode(ext4fs_root, inode_no, inode) == 0)
                return -1;

        return 0;
}

/*
 * Function: ext4fs_get_parent_inode_num
 * Return Value: inode Number of the parent directory of  file/Directory to be
 * created
 * dirname : Input parmater, input path name of the file/directory to be created
 * dname : Output parameter, to be filled with the name of the directory
 * extracted from dirname
 */
int ext4fs_get_parent_inode_num(const char *dirname, char *dname, int flags)
{
        int i;
        int depth = 0;
        int matched_inode_no;
        int result_inode_no = -1;
        char **ptr = NULL;
        char *depth_dirname = NULL;
        char *parse_dirname = NULL;
        struct ext2_inode *parent_inode = NULL;
        struct ext2_inode *first_inode = NULL;
        struct ext2_inode temp_inode;

        if (*dirname != '/') {
                printf("Please supply Absolute path\n");
                return -1;
        }

        /* TODO: input validation make equivalent to linux */
        depth_dirname = zalloc(strlen(dirname) + 1);
        if (!depth_dirname)
                return -ENOMEM;

        memcpy(depth_dirname, dirname, strlen(dirname));
        depth = find_dir_depth(depth_dirname);
        parse_dirname = zalloc(strlen(dirname) + 1);
        if (!parse_dirname)
                goto fail;
        memcpy(parse_dirname, dirname, strlen(dirname));

        /* allocate memory for each directory level */
        ptr = zalloc((depth) * sizeof(char *));
        if (!ptr)
                goto fail;
        if (parse_path(ptr, parse_dirname))
                goto fail;
        parent_inode = zalloc(sizeof(struct ext2_inode));
        if (!parent_inode)
                goto fail;
        first_inode = zalloc(sizeof(struct ext2_inode));
        if (!first_inode)
                goto fail;
        memcpy(parent_inode, ext4fs_root->inode, sizeof(struct ext2_inode));
        memcpy(first_inode, parent_inode, sizeof(struct ext2_inode));
        if (flags & F_FILE)
                result_inode_no = EXT2_ROOT_INO;
        for (i = 1; i < depth; i++) {
                matched_inode_no = search_dir(parent_inode, ptr[i]);
                if (matched_inode_no == -1) {
                        if (ptr[i + 1] == NULL && i == 1) {
                                result_inode_no = EXT2_ROOT_INO;
                                goto end;
                        } else {
                                if (ptr[i + 1] == NULL)
                                        break;
                                printf("Invalid path\n");
                                result_inode_no = -1;
                                goto fail;
                        }
                } else {
                        if (ptr[i + 1] != NULL) {
                                memset(parent_inode, '\0',
                                       sizeof(struct ext2_inode));
                                if (ext4fs_iget(matched_inode_no,
                                                parent_inode)) {
                                        result_inode_no = -1;
                                        goto fail;
                                }
                                result_inode_no = matched_inode_no;
                        } else {
                                break;
                        }
                }
        }

end:
        if (i == 1)
                matched_inode_no = search_dir(first_inode, ptr[i]);
        else
                matched_inode_no = search_dir(parent_inode, ptr[i]);

        if (matched_inode_no != -1) {
                ext4fs_iget(matched_inode_no, &temp_inode);
                if (le16_to_cpu(temp_inode.mode) & S_IFDIR) {
                        printf("It is a Directory\n");
                        result_inode_no = -1;
                        goto fail;
                }
        }

        if (strlen(ptr[i]) > 256) {
                result_inode_no = -1;
                goto fail;
        }
        memcpy(dname, ptr[i], strlen(ptr[i]));

fail:
        free(depth_dirname);
        free(parse_dirname);
        for (i = 0; i < depth; i++) {
                if (!ptr[i])
                        break;
                free(ptr[i]);
        }
        free(ptr);
        free(parent_inode);
        free(first_inode);

        return result_inode_no;
}

static int unlink_filename(char *filename, unsigned int blknr)
{
        int status;
        int inodeno = 0;
        int offset;
        char *block_buffer = NULL;
        struct ext2_dirent *dir = NULL;
        struct ext2_dirent *previous_dir;
        struct ext_filesystem *fs = get_fs();
        int ret = -1;
        char *direntname;

        block_buffer = zalloc(fs->blksz);
        if (!block_buffer)
                return -ENOMEM;

        /* read the directory block */
        status = ext4fs_devread((lbaint_t)blknr * fs->sect_perblk, 0,
                                fs->blksz, block_buffer);
        if (status == 0)
                goto fail;

        offset = 0;
        do {
                if (offset & 3) {
                        printf("Badly aligned ext2_dirent\n");
                        break;
                }

                previous_dir = dir;
                dir = (struct ext2_dirent *)(block_buffer + offset);
                direntname = (char *)(dir) + sizeof(struct ext2_dirent);

                int direntlen = le16_to_cpu(dir->direntlen);
                if (direntlen < sizeof(struct ext2_dirent))
                        break;

                if (dir->inode && (strlen(filename) == dir->namelen) &&
                    (strncmp(direntname, filename, dir->namelen) == 0)) {
                        inodeno = le32_to_cpu(dir->inode);
                        break;
                }

                offset += direntlen;

        } while (offset < fs->blksz);

        if (inodeno > 0) {
                printf("file found, deleting\n");
                if (ext4fs_log_journal(block_buffer, blknr))
                        goto fail;

                if (previous_dir) {
                        /* merge dir entry with predecessor */
                        uint16_t new_len;
                        new_len = le16_to_cpu(previous_dir->direntlen);
                        new_len += le16_to_cpu(dir->direntlen);
                        previous_dir->direntlen = cpu_to_le16(new_len);
                } else {
                        /* invalidate dir entry */
                        dir->inode = 0;
                }
                if (ext4fs_put_metadata(block_buffer, blknr))
                        goto fail;
                ret = inodeno;
        }
fail:
        free(block_buffer);

        return ret;
}

int ext4fs_filename_unlink(char *filename)
{
        int blk_idx;
        long int blknr = -1;
        int inodeno = -1;
        uint32_t directory_blocks;

        directory_blocks = le32_to_cpu(g_parent_inode->size) >>
                LOG2_BLOCK_SIZE(ext4fs_root);

        /* read the block no allocated to a file */
        for (blk_idx = 0; blk_idx < directory_blocks; blk_idx++) {
                blknr = read_allocated_block(g_parent_inode, blk_idx);
                if (blknr <= 0)
                        break;
                inodeno = unlink_filename(filename, blknr);
                if (inodeno != -1)
                        return inodeno;
        }

        return -1;
}

uint32_t ext4fs_get_new_blk_no(void)
{
        short i;
        short status;
        int remainder;
        unsigned int bg_idx;
        static int prev_bg_bitmap_index = -1;
        unsigned int blk_per_grp = le32_to_cpu(ext4fs_root->sblock.blocks_per_group);
        struct ext_filesystem *fs = get_fs();
        char *journal_buffer = zalloc(fs->blksz);
        char *zero_buffer = zalloc(fs->blksz);
        if (!journal_buffer || !zero_buffer)
                goto fail;

        if (fs->first_pass_bbmap == 0) {
                for (i = 0; i < fs->no_blkgrp; i++) {
                        struct ext2_block_group *bgd = NULL;
                        bgd = ext4fs_get_group_descriptor(fs, i);
                        if (ext4fs_bg_get_free_blocks(bgd, fs)) {
                                uint16_t bg_flags = ext4fs_bg_get_flags(bgd);
                                uint64_t b_bitmap_blk =
                                        ext4fs_bg_get_block_id(bgd, fs);
                                if (bg_flags & EXT4_BG_BLOCK_UNINIT) {
                                        memcpy(fs->blk_bmaps[i], zero_buffer,
                                               fs->blksz);
                                        put_ext4(b_bitmap_blk * fs->blksz,
                                                 fs->blk_bmaps[i], fs->blksz);
                                        bg_flags &= ~EXT4_BG_BLOCK_UNINIT;
                                        ext4fs_bg_set_flags(bgd, bg_flags);
                                }
                                fs->curr_blkno =
                                    _get_new_blk_no(fs->blk_bmaps[i]);
                                if (fs->curr_blkno == -1)
                                        /* block bitmap is completely filled */
                                        continue;
                                fs->curr_blkno = fs->curr_blkno +
                                                (i * fs->blksz * 8);
                                fs->first_pass_bbmap++;
                                ext4fs_bg_free_blocks_dec(bgd, fs);
                                ext4fs_sb_free_blocks_dec(fs->sb);
                                status = ext4fs_devread(b_bitmap_blk *
                                                        fs->sect_perblk,
                                                        0, fs->blksz,
                                                        journal_buffer);

                                if (status == 0)
                                        goto fail;
                                if (ext4fs_log_journal(journal_buffer,
                                                       b_bitmap_blk))
                                        goto fail;
                                goto success;
                        } else {
                                debug("no space left on block group %d\n", i);
                        }
                }

                goto fail;
        } else {
                fs->curr_blkno++;
restart:
                /* get the blockbitmap index respective to blockno */
                bg_idx = fs->curr_blkno / blk_per_grp;
                if (fs->blksz == 1024) {
                        remainder = fs->curr_blkno % blk_per_grp;
                        if (!remainder)
                                bg_idx--;
                }

                /*
                 * To skip completely filled block group bitmaps
                 * Optimize the block allocation
                 */
                if (bg_idx >= fs->no_blkgrp)
                        goto fail;

                struct ext2_block_group *bgd = NULL;
                bgd = ext4fs_get_group_descriptor(fs, bg_idx);
                if (ext4fs_bg_get_free_blocks(bgd, fs) == 0) {
                        debug("block group %u is full. Skipping\n", bg_idx);
                        fs->curr_blkno = (bg_idx + 1) * blk_per_grp;
                        if (fs->blksz == 1024)
                                fs->curr_blkno += 1;
                        goto restart;
                }

                uint16_t bg_flags = ext4fs_bg_get_flags(bgd);
                uint64_t b_bitmap_blk = ext4fs_bg_get_block_id(bgd, fs);
                if (bg_flags & EXT4_BG_BLOCK_UNINIT) {
                        memcpy(fs->blk_bmaps[bg_idx], zero_buffer, fs->blksz);
                        put_ext4(b_bitmap_blk * fs->blksz,
                                 zero_buffer, fs->blksz);
                        bg_flags &= ~EXT4_BG_BLOCK_UNINIT;
                        ext4fs_bg_set_flags(bgd, bg_flags);
                }

                if (ext4fs_set_block_bmap(fs->curr_blkno, fs->blk_bmaps[bg_idx],
                                   bg_idx) != 0) {
                        debug("going for restart for the block no %ld %u\n",
                              fs->curr_blkno, bg_idx);
                        fs->curr_blkno++;
                        goto restart;
                }

                /* journal backup */
                if (prev_bg_bitmap_index != bg_idx) {
                        status = ext4fs_devread(b_bitmap_blk * fs->sect_perblk,
                                                0, fs->blksz, journal_buffer);
                        if (status == 0)
                                goto fail;
                        if (ext4fs_log_journal(journal_buffer, b_bitmap_blk))
                                goto fail;

                        prev_bg_bitmap_index = bg_idx;
                }
                ext4fs_bg_free_blocks_dec(bgd, fs);
                ext4fs_sb_free_blocks_dec(fs->sb);
                goto success;
        }
success:
        free(journal_buffer);
        free(zero_buffer);

        return fs->curr_blkno;
fail:
        free(journal_buffer);
        free(zero_buffer);

        return -1;
}

int ext4fs_get_new_inode_no(void)
{
        short i;
        short status;
        unsigned int ibmap_idx;
        static int prev_inode_bitmap_index = -1;
        unsigned int inodes_per_grp = le32_to_cpu(ext4fs_root->sblock.inodes_per_group);
        struct ext_filesystem *fs = get_fs();
        char *journal_buffer = zalloc(fs->blksz);
        char *zero_buffer = zalloc(fs->blksz);
        if (!journal_buffer || !zero_buffer)
                goto fail;
        int has_gdt_chksum = le32_to_cpu(fs->sb->feature_ro_compat) &
                EXT4_FEATURE_RO_COMPAT_GDT_CSUM ? 1 : 0;

        if (fs->first_pass_ibmap == 0) {
                for (i = 0; i < fs->no_blkgrp; i++) {
                        uint32_t free_inodes;
                        struct ext2_block_group *bgd = NULL;
                        bgd = ext4fs_get_group_descriptor(fs, i);
                        free_inodes = ext4fs_bg_get_free_inodes(bgd, fs);
                        if (free_inodes) {
                                uint16_t bg_flags = ext4fs_bg_get_flags(bgd);
                                uint64_t i_bitmap_blk =
                                        ext4fs_bg_get_inode_id(bgd, fs);
                                if (has_gdt_chksum)
                                        bgd->bg_itable_unused = free_inodes;
                                if (bg_flags & EXT4_BG_INODE_UNINIT) {
                                        put_ext4(i_bitmap_blk * fs->blksz,
                                                 zero_buffer, fs->blksz);
                                        bg_flags &= ~EXT4_BG_INODE_UNINIT;
                                        ext4fs_bg_set_flags(bgd, bg_flags);
                                        memcpy(fs->inode_bmaps[i],
                                               zero_buffer, fs->blksz);
                                }
                                fs->curr_inode_no =
                                    _get_new_inode_no(fs->inode_bmaps[i]);
                                if (fs->curr_inode_no == -1)
                                        /* inode bitmap is completely filled */
                                        continue;
                                fs->curr_inode_no = fs->curr_inode_no +
                                                        (i * inodes_per_grp);
                                fs->first_pass_ibmap++;
                                ext4fs_bg_free_inodes_dec(bgd, fs);
                                if (has_gdt_chksum)
                                        ext4fs_bg_itable_unused_dec(bgd, fs);
                                ext4fs_sb_free_inodes_dec(fs->sb);
                                status = ext4fs_devread(i_bitmap_blk *
                                                        fs->sect_perblk,
                                                        0, fs->blksz,
                                                        journal_buffer);
                                if (status == 0)
                                        goto fail;
                                if (ext4fs_log_journal(journal_buffer,
                                                       i_bitmap_blk))
                                        goto fail;
                                goto success;
                        } else
                                debug("no inode left on block group %d\n", i);
                }
                goto fail;
        } else {
restart:
                fs->curr_inode_no++;
                /* get the blockbitmap index respective to blockno */
                ibmap_idx = fs->curr_inode_no / inodes_per_grp;
                struct ext2_block_group *bgd =
                        ext4fs_get_group_descriptor(fs, ibmap_idx);
                uint16_t bg_flags = ext4fs_bg_get_flags(bgd);
                uint64_t i_bitmap_blk = ext4fs_bg_get_inode_id(bgd, fs);

                if (bg_flags & EXT4_BG_INODE_UNINIT) {
                        put_ext4(i_bitmap_blk * fs->blksz,
                                 zero_buffer, fs->blksz);
                        bg_flags &= ~EXT4_BG_INODE_UNINIT;
                        ext4fs_bg_set_flags(bgd, bg_flags);
                        memcpy(fs->inode_bmaps[ibmap_idx], zero_buffer,
                                fs->blksz);
                }

                if (ext4fs_set_inode_bmap(fs->curr_inode_no,
                                          fs->inode_bmaps[ibmap_idx],
                                          ibmap_idx) != 0) {
                        debug("going for restart for the block no %d %u\n",
                              fs->curr_inode_no, ibmap_idx);
                        goto restart;
                }

                /* journal backup */
                if (prev_inode_bitmap_index != ibmap_idx) {
                        status = ext4fs_devread(i_bitmap_blk * fs->sect_perblk,
                                                0, fs->blksz, journal_buffer);
                        if (status == 0)
                                goto fail;
                        if (ext4fs_log_journal(journal_buffer,
                                                le32_to_cpu(bgd->inode_id)))
                                goto fail;
                        prev_inode_bitmap_index = ibmap_idx;
                }
                ext4fs_bg_free_inodes_dec(bgd, fs);
                if (has_gdt_chksum)
                        bgd->bg_itable_unused = bgd->free_inodes;
                ext4fs_sb_free_inodes_dec(fs->sb);
                goto success;
        }

success:
        free(journal_buffer);
        free(zero_buffer);

        return fs->curr_inode_no;
fail:
        free(journal_buffer);
        free(zero_buffer);

        return -1;

}


static void alloc_single_indirect_block(struct ext2_inode *file_inode,
                                        unsigned int *total_remaining_blocks,
                                        unsigned int *no_blks_reqd)
{
        short i;
        short status;
        long int actual_block_no;
        long int si_blockno;
        /* si :single indirect */
        __le32 *si_buffer = NULL;
        __le32 *si_start_addr = NULL;
        struct ext_filesystem *fs = get_fs();

        if (*total_remaining_blocks != 0) {
                si_buffer = zalloc(fs->blksz);
                if (!si_buffer) {
                        printf("No Memory\n");
                        return;
                }
                si_start_addr = si_buffer;
                si_blockno = ext4fs_get_new_blk_no();
                if (si_blockno == -1) {
                        printf("no block left to assign\n");
                        goto fail;
                }
                (*no_blks_reqd)++;
                debug("SIPB %ld: %u\n", si_blockno, *total_remaining_blocks);

                status = ext4fs_devread((lbaint_t)si_blockno * fs->sect_perblk,
                                        0, fs->blksz, (char *)si_buffer);
                memset(si_buffer, '\0', fs->blksz);
                if (status == 0)
                        goto fail;

                for (i = 0; i < (fs->blksz / sizeof(int)); i++) {
                        actual_block_no = ext4fs_get_new_blk_no();
                        if (actual_block_no == -1) {
                                printf("no block left to assign\n");
                                goto fail;
                        }
                        *si_buffer = cpu_to_le32(actual_block_no);
                        debug("SIAB %u: %u\n", *si_buffer,
                                *total_remaining_blocks);

                        si_buffer++;
                        (*total_remaining_blocks)--;
                        if (*total_remaining_blocks == 0)
                                break;
                }

                /* write the block to disk */
                put_ext4(((uint64_t) ((uint64_t)si_blockno * (uint64_t)fs->blksz)),
                         si_start_addr, fs->blksz);
                file_inode->b.blocks.indir_block = cpu_to_le32(si_blockno);
        }
fail:
        free(si_start_addr);
}

static void alloc_double_indirect_block(struct ext2_inode *file_inode,
                                        unsigned int *total_remaining_blocks,
                                        unsigned int *no_blks_reqd)
{
        short i;
        short j;
        short status;
        long int actual_block_no;
        /* di:double indirect */
        long int di_blockno_parent;
        long int di_blockno_child;
        __le32 *di_parent_buffer = NULL;
        __le32 *di_child_buff = NULL;
        __le32 *di_block_start_addr = NULL;
        __le32 *di_child_buff_start = NULL;
        struct ext_filesystem *fs = get_fs();

        if (*total_remaining_blocks != 0) {
                /* double indirect parent block connecting to inode */
                di_blockno_parent = ext4fs_get_new_blk_no();
                if (di_blockno_parent == -1) {
                        printf("no block left to assign\n");
                        goto fail;
                }
                di_parent_buffer = zalloc(fs->blksz);
                if (!di_parent_buffer)
                        goto fail;

                di_block_start_addr = di_parent_buffer;
                (*no_blks_reqd)++;
                debug("DIPB %ld: %u\n", di_blockno_parent,
                      *total_remaining_blocks);

                status = ext4fs_devread((lbaint_t)di_blockno_parent *
                                        fs->sect_perblk, 0,
                                        fs->blksz, (char *)di_parent_buffer);

                if (!status) {
                        printf("%s: Device read error!\n", __func__);
                        goto fail;
                }
                memset(di_parent_buffer, '\0', fs->blksz);

                /*
                 * start:for each double indirect parent
                 * block create one more block
                 */
                for (i = 0; i < (fs->blksz / sizeof(int)); i++) {
                        di_blockno_child = ext4fs_get_new_blk_no();
                        if (di_blockno_child == -1) {
                                printf("no block left to assign\n");
                                goto fail;
                        }
                        di_child_buff = zalloc(fs->blksz);
                        if (!di_child_buff)
                                goto fail;

                        di_child_buff_start = di_child_buff;
                        *di_parent_buffer = cpu_to_le32(di_blockno_child);
                        di_parent_buffer++;
                        (*no_blks_reqd)++;
                        debug("DICB %ld: %u\n", di_blockno_child,
                              *total_remaining_blocks);

                        status = ext4fs_devread((lbaint_t)di_blockno_child *
                                                fs->sect_perblk, 0,
                                                fs->blksz,
                                                (char *)di_child_buff);

                        if (!status) {
                                printf("%s: Device read error!\n", __func__);
                                goto fail;
                        }
                        memset(di_child_buff, '\0', fs->blksz);
                        /* filling of actual datablocks for each child */
                        for (j = 0; j < (fs->blksz / sizeof(int)); j++) {
                                actual_block_no = ext4fs_get_new_blk_no();
                                if (actual_block_no == -1) {
                                        printf("no block left to assign\n");
                                        goto fail;
                                }
                                *di_child_buff = cpu_to_le32(actual_block_no);
                                debug("DIAB %ld: %u\n", actual_block_no,
                                      *total_remaining_blocks);

                                di_child_buff++;
                                (*total_remaining_blocks)--;
                                if (*total_remaining_blocks == 0)
                                        break;
                        }
                        /* write the block  table */
                        put_ext4(((uint64_t) ((uint64_t)di_blockno_child * (uint64_t)fs->blksz)),
                                 di_child_buff_start, fs->blksz);
                        free(di_child_buff_start);
                        di_child_buff_start = NULL;

                        if (*total_remaining_blocks == 0)
                                break;
                }
                put_ext4(((uint64_t) ((uint64_t)di_blockno_parent * (uint64_t)fs->blksz)),
                         di_block_start_addr, fs->blksz);
                file_inode->b.blocks.double_indir_block = cpu_to_le32(di_blockno_parent);
        }
fail:
        free(di_block_start_addr);
}

static void alloc_triple_indirect_block(struct ext2_inode *file_inode,
                                        unsigned int *total_remaining_blocks,
                                        unsigned int *no_blks_reqd)
{
        short i;
        short j;
        short k;
        long int actual_block_no;
        /* ti: Triple Indirect */
        long int ti_gp_blockno;
        long int ti_parent_blockno;
        long int ti_child_blockno;
        __le32 *ti_gp_buff = NULL;
        __le32 *ti_parent_buff = NULL;
        __le32 *ti_child_buff = NULL;
        __le32 *ti_gp_buff_start_addr = NULL;
        __le32 *ti_pbuff_start_addr = NULL;
        __le32 *ti_cbuff_start_addr = NULL;
        struct ext_filesystem *fs = get_fs();
        if (*total_remaining_blocks != 0) {
                /* triple indirect grand parent block connecting to inode */
                ti_gp_blockno = ext4fs_get_new_blk_no();
                if (ti_gp_blockno == -1) {
                        printf("no block left to assign\n");
                        return;
                }
                ti_gp_buff = zalloc(fs->blksz);
                if (!ti_gp_buff)
                        return;

                ti_gp_buff_start_addr = ti_gp_buff;
                (*no_blks_reqd)++;
                debug("TIGPB %ld: %u\n", ti_gp_blockno,
                      *total_remaining_blocks);

                /* for each 4 byte grand parent entry create one more block */
                for (i = 0; i < (fs->blksz / sizeof(int)); i++) {
                        ti_parent_blockno = ext4fs_get_new_blk_no();
                        if (ti_parent_blockno == -1) {
                                printf("no block left to assign\n");
                                goto fail;
                        }
                        ti_parent_buff = zalloc(fs->blksz);
                        if (!ti_parent_buff)
                                goto fail;

                        ti_pbuff_start_addr = ti_parent_buff;
                        *ti_gp_buff = cpu_to_le32(ti_parent_blockno);
                        ti_gp_buff++;
                        (*no_blks_reqd)++;
                        debug("TIPB %ld: %u\n", ti_parent_blockno,
                              *total_remaining_blocks);

                        /* for each 4 byte entry parent create one more block */
                        for (j = 0; j < (fs->blksz / sizeof(int)); j++) {
                                ti_child_blockno = ext4fs_get_new_blk_no();
                                if (ti_child_blockno == -1) {
                                        printf("no block left assign\n");
                                        goto fail1;
                                }
                                ti_child_buff = zalloc(fs->blksz);
                                if (!ti_child_buff)
                                        goto fail1;

                                ti_cbuff_start_addr = ti_child_buff;
                                *ti_parent_buff = cpu_to_le32(ti_child_blockno);
                                ti_parent_buff++;
                                (*no_blks_reqd)++;
                                debug("TICB %ld: %u\n", ti_parent_blockno,
                                      *total_remaining_blocks);

                                /* fill actual datablocks for each child */
                                for (k = 0; k < (fs->blksz / sizeof(int));
                                        k++) {
                                        actual_block_no =
                                            ext4fs_get_new_blk_no();
                                        if (actual_block_no == -1) {
                                                printf("no block left\n");
                                                free(ti_cbuff_start_addr);
                                                goto fail1;
                                        }
                                        *ti_child_buff = cpu_to_le32(actual_block_no);
                                        debug("TIAB %ld: %u\n", actual_block_no,
                                              *total_remaining_blocks);

                                        ti_child_buff++;
                                        (*total_remaining_blocks)--;
                                        if (*total_remaining_blocks == 0)
                                                break;
                                }
                                /* write the child block */
                                put_ext4(((uint64_t) ((uint64_t)ti_child_blockno *
                                                      (uint64_t)fs->blksz)),
                                         ti_cbuff_start_addr, fs->blksz);
                                free(ti_cbuff_start_addr);

                                if (*total_remaining_blocks == 0)
                                        break;
                        }
                        /* write the parent block */
                        put_ext4(((uint64_t) ((uint64_t)ti_parent_blockno * (uint64_t)fs->blksz)),
                                 ti_pbuff_start_addr, fs->blksz);
                        free(ti_pbuff_start_addr);

                        if (*total_remaining_blocks == 0)
                                break;
                }
                /* write the grand parent block */
                put_ext4(((uint64_t) ((uint64_t)ti_gp_blockno * (uint64_t)fs->blksz)),
                         ti_gp_buff_start_addr, fs->blksz);
                file_inode->b.blocks.triple_indir_block = cpu_to_le32(ti_gp_blockno);
                free(ti_gp_buff_start_addr);
                return;
        }
fail1:
        free(ti_pbuff_start_addr);
fail:
        free(ti_gp_buff_start_addr);
}

void ext4fs_allocate_blocks(struct ext2_inode *file_inode,
                                unsigned int total_remaining_blocks,
                                unsigned int *total_no_of_block)
{
        short i;
        long int direct_blockno;
        unsigned int no_blks_reqd = 0;

        /* allocation of direct blocks */
        for (i = 0; total_remaining_blocks && i < INDIRECT_BLOCKS; i++) {
                direct_blockno = ext4fs_get_new_blk_no();
                if (direct_blockno == -1) {
                        printf("no block left to assign\n");
                        return;
                }
                file_inode->b.blocks.dir_blocks[i] = cpu_to_le32(direct_blockno);
                debug("DB %ld: %u\n", direct_blockno, total_remaining_blocks);

                total_remaining_blocks--;
        }

        alloc_single_indirect_block(file_inode, &total_remaining_blocks,
                                    &no_blks_reqd);
        alloc_double_indirect_block(file_inode, &total_remaining_blocks,
                                    &no_blks_reqd);
        alloc_triple_indirect_block(file_inode, &total_remaining_blocks,
                                    &no_blks_reqd);
        *total_no_of_block += no_blks_reqd;
}

#endif

static struct ext4_extent_header *ext4fs_get_extent_block
        (struct ext2_data *data, char *buf,
                struct ext4_extent_header *ext_block,
                uint32_t fileblock, int log2_blksz)
{
        struct ext4_extent_idx *index;
        unsigned long long block;
        int blksz = EXT2_BLOCK_SIZE(data);
        int i;

        while (1) {
                index = (struct ext4_extent_idx *)(ext_block + 1);

                if (le16_to_cpu(ext_block->eh_magic) != EXT4_EXT_MAGIC)
                        return NULL;

                if (ext_block->eh_depth == 0)
                        return ext_block;
                i = -1;
                do {
                        i++;
                        if (i >= le16_to_cpu(ext_block->eh_entries))
                                break;
                } while (fileblock >= le32_to_cpu(index[i].ei_block));

                if (--i < 0)
                        return NULL;

                block = le16_to_cpu(index[i].ei_leaf_hi);
                block = (block << 32) + le32_to_cpu(index[i].ei_leaf_lo);

                if (ext4fs_devread((lbaint_t)block << log2_blksz, 0, blksz,
                                   buf))
                        ext_block = (struct ext4_extent_header *)buf;
                else
                        return NULL;
        }
}

static int ext4fs_blockgroup
        (struct ext2_data *data, int group, struct ext2_block_group *blkgrp)
{
        long int blkno;
        unsigned int blkoff, desc_per_blk;
        int log2blksz = get_fs()->dev_desc->log2blksz;
        int desc_size = get_fs()->gdsize;

        desc_per_blk = EXT2_BLOCK_SIZE(data) / desc_size;

        blkno = le32_to_cpu(data->sblock.first_data_block) + 1 +
                        group / desc_per_blk;
        blkoff = (group % desc_per_blk) * desc_size;

        debug("ext4fs read %d group descriptor (blkno %ld blkoff %u)\n",
              group, blkno, blkoff);

        return ext4fs_devread((lbaint_t)blkno <<
                              (LOG2_BLOCK_SIZE(data) - log2blksz),
                              blkoff, desc_size, (char *)blkgrp);
}

int ext4fs_read_inode(struct ext2_data *data, int ino, struct ext2_inode *inode)
{
        struct ext2_block_group blkgrp;
        struct ext2_sblock *sblock = &data->sblock;
        struct ext_filesystem *fs = get_fs();
        int log2blksz = get_fs()->dev_desc->log2blksz;
        int inodes_per_block, status;
        long int blkno;
        unsigned int blkoff;

        /* It is easier to calculate if the first inode is 0. */
        ino--;
        status = ext4fs_blockgroup(data, ino / le32_to_cpu
                                   (sblock->inodes_per_group), &blkgrp);
        if (status == 0)
                return 0;

        inodes_per_block = EXT2_BLOCK_SIZE(data) / fs->inodesz;
        blkno = ext4fs_bg_get_inode_table_id(&blkgrp, fs) +
            (ino % le32_to_cpu(sblock->inodes_per_group)) / inodes_per_block;
        blkoff = (ino % inodes_per_block) * fs->inodesz;
        /* Read the inode. */
        status = ext4fs_devread((lbaint_t)blkno << (LOG2_BLOCK_SIZE(data) -
                                log2blksz), blkoff,
                                sizeof(struct ext2_inode), (char *)inode);
        if (status == 0)
                return 0;

        return 1;
}

long int read_allocated_block(struct ext2_inode *inode, int fileblock)
{
        long int blknr;
        int blksz;
        int log2_blksz;
        int status;
        long int rblock;
        long int perblock_parent;
        long int perblock_child;
        unsigned long long start;
        /* get the blocksize of the filesystem */
        blksz = EXT2_BLOCK_SIZE(ext4fs_root);
        log2_blksz = LOG2_BLOCK_SIZE(ext4fs_root)
                - get_fs()->dev_desc->log2blksz;

        if (le32_to_cpu(inode->flags) & EXT4_EXTENTS_FL) {
                long int startblock, endblock;
                char *buf = zalloc(blksz);
                if (!buf)
                        return -ENOMEM;
                struct ext4_extent_header *ext_block;
                struct ext4_extent *extent;
                int i;
                ext_block =
                        ext4fs_get_extent_block(ext4fs_root, buf,
                                                (struct ext4_extent_header *)
                                                inode->b.blocks.dir_blocks,
                                                fileblock, log2_blksz);
                if (!ext_block) {
                        printf("invalid extent block\n");
                        free(buf);
                        return -EINVAL;
                }

                extent = (struct ext4_extent *)(ext_block + 1);

                for (i = 0; i < le16_to_cpu(ext_block->eh_entries); i++) {
                        startblock = le32_to_cpu(extent[i].ee_block);
                        endblock = startblock + le16_to_cpu(extent[i].ee_len);

                        if (startblock > fileblock) {
                                /* Sparse file */
                                free(buf);
                                return 0;

                        } else if (fileblock < endblock) {
                                start = le16_to_cpu(extent[i].ee_start_hi);
                                start = (start << 32) +
                                        le32_to_cpu(extent[i].ee_start_lo);
                                free(buf);
                                return (fileblock - startblock) + start;
                        }
                }

                free(buf);
                return 0;
        }

        /* Direct blocks. */
        if (fileblock < INDIRECT_BLOCKS)
                blknr = le32_to_cpu(inode->b.blocks.dir_blocks[fileblock]);

        /* Indirect. */
        else if (fileblock < (INDIRECT_BLOCKS + (blksz / 4))) {
                if (ext4fs_indir1_block == NULL) {
                        ext4fs_indir1_block = zalloc(blksz);
                        if (ext4fs_indir1_block == NULL) {
                                printf("** SI ext2fs read block (indir 1)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_size = blksz;
                        ext4fs_indir1_blkno = -1;
                }
                if (blksz != ext4fs_indir1_size) {
                        free(ext4fs_indir1_block);
                        ext4fs_indir1_block = NULL;
                        ext4fs_indir1_size = 0;
                        ext4fs_indir1_blkno = -1;
                        ext4fs_indir1_block = zalloc(blksz);
                        if (ext4fs_indir1_block == NULL) {
                                printf("** SI ext2fs read block (indir 1):"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_size = blksz;
                }
                if ((le32_to_cpu(inode->b.blocks.indir_block) <<
                     log2_blksz) != ext4fs_indir1_blkno) {
                        status =
                            ext4fs_devread((lbaint_t)le32_to_cpu
                                           (inode->b.blocks.
                                            indir_block) << log2_blksz, 0,
                                           blksz, (char *)ext4fs_indir1_block);
                        if (status == 0) {
                                printf("** SI ext2fs read block (indir 1)"
                                        "failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_blkno =
                                le32_to_cpu(inode->b.blocks.
                                               indir_block) << log2_blksz;
                }
                blknr = le32_to_cpu(ext4fs_indir1_block
                                      [fileblock - INDIRECT_BLOCKS]);
        }
        /* Double indirect. */
        else if (fileblock < (INDIRECT_BLOCKS + (blksz / 4 *
                                        (blksz / 4 + 1)))) {

                long int perblock = blksz / 4;
                long int rblock = fileblock - (INDIRECT_BLOCKS + blksz / 4);

                if (ext4fs_indir1_block == NULL) {
                        ext4fs_indir1_block = zalloc(blksz);
                        if (ext4fs_indir1_block == NULL) {
                                printf("** DI ext2fs read block (indir 2 1)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_size = blksz;
                        ext4fs_indir1_blkno = -1;
                }
                if (blksz != ext4fs_indir1_size) {
                        free(ext4fs_indir1_block);
                        ext4fs_indir1_block = NULL;
                        ext4fs_indir1_size = 0;
                        ext4fs_indir1_blkno = -1;
                        ext4fs_indir1_block = zalloc(blksz);
                        if (ext4fs_indir1_block == NULL) {
                                printf("** DI ext2fs read block (indir 2 1)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_size = blksz;
                }
                if ((le32_to_cpu(inode->b.blocks.double_indir_block) <<
                     log2_blksz) != ext4fs_indir1_blkno) {
                        status =
                            ext4fs_devread((lbaint_t)le32_to_cpu
                                           (inode->b.blocks.
                                            double_indir_block) << log2_blksz,
                                           0, blksz,
                                           (char *)ext4fs_indir1_block);
                        if (status == 0) {
                                printf("** DI ext2fs read block (indir 2 1)"
                                        "failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_blkno =
                            le32_to_cpu(inode->b.blocks.double_indir_block) <<
                            log2_blksz;
                }

                if (ext4fs_indir2_block == NULL) {
                        ext4fs_indir2_block = zalloc(blksz);
                        if (ext4fs_indir2_block == NULL) {
                                printf("** DI ext2fs read block (indir 2 2)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir2_size = blksz;
                        ext4fs_indir2_blkno = -1;
                }
                if (blksz != ext4fs_indir2_size) {
                        free(ext4fs_indir2_block);
                        ext4fs_indir2_block = NULL;
                        ext4fs_indir2_size = 0;
                        ext4fs_indir2_blkno = -1;
                        ext4fs_indir2_block = zalloc(blksz);
                        if (ext4fs_indir2_block == NULL) {
                                printf("** DI ext2fs read block (indir 2 2)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir2_size = blksz;
                }
                if ((le32_to_cpu(ext4fs_indir1_block[rblock / perblock]) <<
                     log2_blksz) != ext4fs_indir2_blkno) {
                        status = ext4fs_devread((lbaint_t)le32_to_cpu
                                                (ext4fs_indir1_block
                                                 [rblock /
                                                  perblock]) << log2_blksz, 0,
                                                blksz,
                                                (char *)ext4fs_indir2_block);
                        if (status == 0) {
                                printf("** DI ext2fs read block (indir 2 2)"
                                        "failed. **\n");
                                return -1;
                        }
                        ext4fs_indir2_blkno =
                            le32_to_cpu(ext4fs_indir1_block[rblock
                                                              /
                                                              perblock]) <<
                            log2_blksz;
                }
                blknr = le32_to_cpu(ext4fs_indir2_block[rblock % perblock]);
        }
        /* Tripple indirect. */
        else {
                rblock = fileblock - (INDIRECT_BLOCKS + blksz / 4 +
                                      (blksz / 4 * blksz / 4));
                perblock_child = blksz / 4;
                perblock_parent = ((blksz / 4) * (blksz / 4));

                if (ext4fs_indir1_block == NULL) {
                        ext4fs_indir1_block = zalloc(blksz);
                        if (ext4fs_indir1_block == NULL) {
                                printf("** TI ext2fs read block (indir 2 1)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_size = blksz;
                        ext4fs_indir1_blkno = -1;
                }
                if (blksz != ext4fs_indir1_size) {
                        free(ext4fs_indir1_block);
                        ext4fs_indir1_block = NULL;
                        ext4fs_indir1_size = 0;
                        ext4fs_indir1_blkno = -1;
                        ext4fs_indir1_block = zalloc(blksz);
                        if (ext4fs_indir1_block == NULL) {
                                printf("** TI ext2fs read block (indir 2 1)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_size = blksz;
                }
                if ((le32_to_cpu(inode->b.blocks.triple_indir_block) <<
                     log2_blksz) != ext4fs_indir1_blkno) {
                        status = ext4fs_devread
                            ((lbaint_t)
                             le32_to_cpu(inode->b.blocks.triple_indir_block)
                             << log2_blksz, 0, blksz,
                             (char *)ext4fs_indir1_block);
                        if (status == 0) {
                                printf("** TI ext2fs read block (indir 2 1)"
                                        "failed. **\n");
                                return -1;
                        }
                        ext4fs_indir1_blkno =
                            le32_to_cpu(inode->b.blocks.triple_indir_block) <<
                            log2_blksz;
                }

                if (ext4fs_indir2_block == NULL) {
                        ext4fs_indir2_block = zalloc(blksz);
                        if (ext4fs_indir2_block == NULL) {
                                printf("** TI ext2fs read block (indir 2 2)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir2_size = blksz;
                        ext4fs_indir2_blkno = -1;
                }
                if (blksz != ext4fs_indir2_size) {
                        free(ext4fs_indir2_block);
                        ext4fs_indir2_block = NULL;
                        ext4fs_indir2_size = 0;
                        ext4fs_indir2_blkno = -1;
                        ext4fs_indir2_block = zalloc(blksz);
                        if (ext4fs_indir2_block == NULL) {
                                printf("** TI ext2fs read block (indir 2 2)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir2_size = blksz;
                }
                if ((le32_to_cpu(ext4fs_indir1_block[rblock /
                                                       perblock_parent]) <<
                     log2_blksz)
                    != ext4fs_indir2_blkno) {
                        status = ext4fs_devread((lbaint_t)le32_to_cpu
                                                (ext4fs_indir1_block
                                                 [rblock /
                                                  perblock_parent]) <<
                                                log2_blksz, 0, blksz,
                                                (char *)ext4fs_indir2_block);
                        if (status == 0) {
                                printf("** TI ext2fs read block (indir 2 2)"
                                        "failed. **\n");
                                return -1;
                        }
                        ext4fs_indir2_blkno =
                            le32_to_cpu(ext4fs_indir1_block[rblock /
                                                              perblock_parent])
                            << log2_blksz;
                }

                if (ext4fs_indir3_block == NULL) {
                        ext4fs_indir3_block = zalloc(blksz);
                        if (ext4fs_indir3_block == NULL) {
                                printf("** TI ext2fs read block (indir 2 2)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir3_size = blksz;
                        ext4fs_indir3_blkno = -1;
                }
                if (blksz != ext4fs_indir3_size) {
                        free(ext4fs_indir3_block);
                        ext4fs_indir3_block = NULL;
                        ext4fs_indir3_size = 0;
                        ext4fs_indir3_blkno = -1;
                        ext4fs_indir3_block = zalloc(blksz);
                        if (ext4fs_indir3_block == NULL) {
                                printf("** TI ext2fs read block (indir 2 2)"
                                        "malloc failed. **\n");
                                return -1;
                        }
                        ext4fs_indir3_size = blksz;
                }
                if ((le32_to_cpu(ext4fs_indir2_block[rblock
                                                       /
                                                       perblock_child]) <<
                     log2_blksz) != ext4fs_indir3_blkno) {
                        status =
                            ext4fs_devread((lbaint_t)le32_to_cpu
                                           (ext4fs_indir2_block
                                            [(rblock / perblock_child)
                                             % (blksz / 4)]) << log2_blksz, 0,
                                           blksz, (char *)ext4fs_indir3_block);
                        if (status == 0) {
                                printf("** TI ext2fs read block (indir 2 2)"
                                       "failed. **\n");
                                return -1;
                        }
                        ext4fs_indir3_blkno =
                            le32_to_cpu(ext4fs_indir2_block[(rblock /
                                                               perblock_child) %
                                                              (blksz /
                                                               4)]) <<
                            log2_blksz;
                }

                blknr = le32_to_cpu(ext4fs_indir3_block
                                      [rblock % perblock_child]);
        }
        debug("read_allocated_block %ld\n", blknr);

        return blknr;
}

/**
 * ext4fs_reinit_global() - Reinitialize values of ext4 write implementation's
 *                          global pointers
 *
 * This function assures that for a file with the same name but different size
 * the sequential store on the ext4 filesystem will be correct.
 *
 * In this function the global data, responsible for internal representation
 * of the ext4 data are initialized to the reset state. Without this, during
 * replacement of the smaller file with the bigger truncation of new file was
 * performed.
 */
void ext4fs_reinit_global(void)
{
        if (ext4fs_indir1_block != NULL) {
                free(ext4fs_indir1_block);
                ext4fs_indir1_block = NULL;
                ext4fs_indir1_size = 0;
                ext4fs_indir1_blkno = -1;
        }
        if (ext4fs_indir2_block != NULL) {
                free(ext4fs_indir2_block);
                ext4fs_indir2_block = NULL;
                ext4fs_indir2_size = 0;
                ext4fs_indir2_blkno = -1;
        }
        if (ext4fs_indir3_block != NULL) {
                free(ext4fs_indir3_block);
                ext4fs_indir3_block = NULL;
                ext4fs_indir3_size = 0;
                ext4fs_indir3_blkno = -1;
        }
}
void ext4fs_close(void)
{
        if ((ext4fs_file != NULL) && (ext4fs_root != NULL)) {
                ext4fs_free_node(ext4fs_file, &ext4fs_root->diropen);
                ext4fs_file = NULL;
        }
        if (ext4fs_root != NULL) {
                free(ext4fs_root);
                ext4fs_root = NULL;

        }

        ext4fs_reinit_global();
}

int ext4fs_iterate_dir(struct ext2fs_node *dir, char *name,
                                struct ext2fs_node **fnode, int *ftype)
{
        unsigned int fpos = 0;
        int status;
        loff_t actread;
        struct ext2fs_node *diro = (struct ext2fs_node *) dir;

#ifdef DEBUG
        if (name != NULL)
                printf("Iterate dir %s\n", name);
#endif /* of DEBUG */
        if (!diro->inode_read) {
                status = ext4fs_read_inode(diro->data, diro->ino, &diro->inode);
                if (status == 0)
                        return 0;
        }
        /* Search the file.  */
        while (fpos < le32_to_cpu(diro->inode.size)) {
                struct ext2_dirent dirent;

                status = ext4fs_read_file(diro, fpos,
                                           sizeof(struct ext2_dirent),
                                           (char *)&dirent, &actread);
                if (status < 0)
                        return 0;

                if (dirent.direntlen == 0) {
                        printf("Failed to iterate over directory %s\n", name);
                        return 0;
                }

                if (dirent.namelen != 0) {
                        char filename[dirent.namelen + 1];
                        struct ext2fs_node *fdiro;
                        int type = FILETYPE_UNKNOWN;

                        status = ext4fs_read_file(diro,
                                                  fpos +
                                                  sizeof(struct ext2_dirent),
                                                  dirent.namelen, filename,
                                                  &actread);
                        if (status < 0)
                                return 0;

                        fdiro = zalloc(sizeof(struct ext2fs_node));
                        if (!fdiro)
                                return 0;

                        fdiro->data = diro->data;
                        fdiro->ino = le32_to_cpu(dirent.inode);

                        filename[dirent.namelen] = '\0';

                        if (dirent.filetype != FILETYPE_UNKNOWN) {
                                fdiro->inode_read = 0;

                                if (dirent.filetype == FILETYPE_DIRECTORY)
                                        type = FILETYPE_DIRECTORY;
                                else if (dirent.filetype == FILETYPE_SYMLINK)
                                        type = FILETYPE_SYMLINK;
                                else if (dirent.filetype == FILETYPE_REG)
                                        type = FILETYPE_REG;
                        } else {
                                status = ext4fs_read_inode(diro->data,
                                                           le32_to_cpu
                                                           (dirent.inode),
                                                           &fdiro->inode);
                                if (status == 0) {
                                        free(fdiro);
                                        return 0;
                                }
                                fdiro->inode_read = 1;

                                if ((le16_to_cpu(fdiro->inode.mode) &
                                     FILETYPE_INO_MASK) ==
                                    FILETYPE_INO_DIRECTORY) {
                                        type = FILETYPE_DIRECTORY;
                                } else if ((le16_to_cpu(fdiro->inode.mode)
                                            & FILETYPE_INO_MASK) ==
                                           FILETYPE_INO_SYMLINK) {
                                        type = FILETYPE_SYMLINK;
                                } else if ((le16_to_cpu(fdiro->inode.mode)
                                            & FILETYPE_INO_MASK) ==
                                           FILETYPE_INO_REG) {
                                        type = FILETYPE_REG;
                                }
                        }
#ifdef DEBUG
                        printf("iterate >%s<\n", filename);
#endif /* of DEBUG */
                        if ((name != NULL) && (fnode != NULL)
                            && (ftype != NULL)) {
                                if (strcmp(filename, name) == 0) {
                                        *ftype = type;
                                        *fnode = fdiro;
                                        return 1;
                                }
                        } else {
                                if (fdiro->inode_read == 0) {
                                        status = ext4fs_read_inode(diro->data,
                                                                 le32_to_cpu(
                                                                 dirent.inode),
                                                                 &fdiro->inode);
                                        if (status == 0) {
                                                free(fdiro);
                                                return 0;
                                        }
                                        fdiro->inode_read = 1;
                                }
                                switch (type) {
                                case FILETYPE_DIRECTORY:
                                        printf("<DIR> ");
                                        break;
                                case FILETYPE_SYMLINK:
                                        printf("<SYM> ");
                                        break;
                                case FILETYPE_REG:
                                        printf("      ");
                                        break;
                                default:
                                        printf("< ? > ");
                                        break;
                                }
                                printf("%10u %s\n",
                                       le32_to_cpu(fdiro->inode.size),
                                        filename);
                        }
                        free(fdiro);
                }
                fpos += le16_to_cpu(dirent.direntlen);
        }
        return 0;
}

static char *ext4fs_read_symlink(struct ext2fs_node *node)
{
        char *symlink;
        struct ext2fs_node *diro = node;
        int status;
        loff_t actread;

        if (!diro->inode_read) {
                status = ext4fs_read_inode(diro->data, diro->ino, &diro->inode);
                if (status == 0)
                        return NULL;
        }
        symlink = zalloc(le32_to_cpu(diro->inode.size) + 1);
        if (!symlink)
                return NULL;

        if (le32_to_cpu(diro->inode.size) < sizeof(diro->inode.b.symlink)) {
                strncpy(symlink, diro->inode.b.symlink,
                         le32_to_cpu(diro->inode.size));
        } else {
                status = ext4fs_read_file(diro, 0,
                                           le32_to_cpu(diro->inode.size),
                                           symlink, &actread);
                if ((status < 0) || (actread == 0)) {
                        free(symlink);
                        return NULL;
                }
        }
        symlink[le32_to_cpu(diro->inode.size)] = '\0';
        return symlink;
}

static int ext4fs_find_file1(const char *currpath,
                             struct ext2fs_node *currroot,
                             struct ext2fs_node **currfound, int *foundtype)
{
        char fpath[strlen(currpath) + 1];
        char *name = fpath;
        char *next;
        int status;
        int type = FILETYPE_DIRECTORY;
        struct ext2fs_node *currnode = currroot;
        struct ext2fs_node *oldnode = currroot;

        strncpy(fpath, currpath, strlen(currpath) + 1);

        /* Remove all leading slashes. */
        while (*name == '/')
                name++;

        if (!*name) {
                *currfound = currnode;
                return 1;
        }

        for (;;) {
                int found;

                /* Extract the actual part from the pathname. */
                next = strchr(name, '/');
                if (next) {
                        /* Remove all leading slashes. */
                        while (*next == '/')
                                *(next++) = '\0';
                }

                if (type != FILETYPE_DIRECTORY) {
                        ext4fs_free_node(currnode, currroot);
                        return 0;
                }

                oldnode = currnode;

                /* Iterate over the directory. */
                found = ext4fs_iterate_dir(currnode, name, &currnode, &type);
                if (found == 0)
                        return 0;

                if (found == -1)
                        break;

                /* Read in the symlink and follow it. */
                if (type == FILETYPE_SYMLINK) {
                        char *symlink;

                        /* Test if the symlink does not loop. */
                        if (++symlinknest == 8) {
                                ext4fs_free_node(currnode, currroot);
                                ext4fs_free_node(oldnode, currroot);
                                return 0;
                        }

                        symlink = ext4fs_read_symlink(currnode);
                        ext4fs_free_node(currnode, currroot);

                        if (!symlink) {
                                ext4fs_free_node(oldnode, currroot);
                                return 0;
                        }

                        debug("Got symlink >%s<\n", symlink);

                        if (symlink[0] == '/') {
                                ext4fs_free_node(oldnode, currroot);
                                oldnode = &ext4fs_root->diropen;
                        }

                        /* Lookup the node the symlink points to. */
                        status = ext4fs_find_file1(symlink, oldnode,
                                                    &currnode, &type);

                        free(symlink);

                        if (status == 0) {
                                ext4fs_free_node(oldnode, currroot);
                                return 0;
                        }
                }

                ext4fs_free_node(oldnode, currroot);

                /* Found the node! */
                if (!next || *next == '\0') {
                        *currfound = currnode;
                        *foundtype = type;
                        return 1;
                }
                name = next;
        }
        return -1;
}

int ext4fs_find_file(const char *path, struct ext2fs_node *rootnode,
        struct ext2fs_node **foundnode, int expecttype)
{
        int status;
        int foundtype = FILETYPE_DIRECTORY;

        symlinknest = 0;
        if (!path)
                return 0;

        status = ext4fs_find_file1(path, rootnode, foundnode, &foundtype);
        if (status == 0)
                return 0;

        /* Check if the node that was found was of the expected type. */
        if ((expecttype == FILETYPE_REG) && (foundtype != expecttype))
                return 0;
        else if ((expecttype == FILETYPE_DIRECTORY)
                   && (foundtype != expecttype))
                return 0;

        return 1;
}

int ext4fs_open(const char *filename, loff_t *len)
{
        struct ext2fs_node *fdiro = NULL;
        int status;

        if (ext4fs_root == NULL)
                return -1;

        ext4fs_file = NULL;
        status = ext4fs_find_file(filename, &ext4fs_root->diropen, &fdiro,
                                  FILETYPE_REG);
        if (status == 0)
                goto fail;

        if (!fdiro->inode_read) {
                status = ext4fs_read_inode(fdiro->data, fdiro->ino,
                                &fdiro->inode);
                if (status == 0)
                        goto fail;
        }
        *len = le32_to_cpu(fdiro->inode.size);
        ext4fs_file = fdiro;

        return 0;
fail:
        ext4fs_free_node(fdiro, &ext4fs_root->diropen);

        return -1;
}

int ext4fs_mount(unsigned part_length)
{
        struct ext2_data *data;
        int status;
        struct ext_filesystem *fs = get_fs();
        data = zalloc(SUPERBLOCK_SIZE);
        if (!data)
                return 0;

        /* Read the superblock. */
        status = ext4_read_superblock((char *)&data->sblock);

        if (status == 0)
                goto fail;

        /* Make sure this is an ext2 filesystem. */
        if (le16_to_cpu(data->sblock.magic) != EXT2_MAGIC)
                goto fail_noerr;


        if (le32_to_cpu(data->sblock.revision_level) == 0) {
                fs->inodesz = 128;
                fs->gdsize = 32;
        } else {
                debug("EXT4 features COMPAT: %08x INCOMPAT: %08x RO_COMPAT: %08x\n",
                      __le32_to_cpu(data->sblock.feature_compatibility),
                      __le32_to_cpu(data->sblock.feature_incompat),
                      __le32_to_cpu(data->sblock.feature_ro_compat));

                fs->inodesz = le16_to_cpu(data->sblock.inode_size);
                fs->gdsize = le32_to_cpu(data->sblock.feature_incompat) &
                        EXT4_FEATURE_INCOMPAT_64BIT ?
                        le16_to_cpu(data->sblock.descriptor_size) : 32;
        }

        debug("EXT2 rev %d, inode_size %d, descriptor size %d\n",
              le32_to_cpu(data->sblock.revision_level),
              fs->inodesz, fs->gdsize);

        data->diropen.data = data;
        data->diropen.ino = 2;
        data->diropen.inode_read = 1;
        data->inode = &data->diropen.inode;

        status = ext4fs_read_inode(data, 2, data->inode);
        if (status == 0)
                goto fail;

        ext4fs_root = data;

        return 1;
fail:
        printf("Failed to mount ext2 filesystem...\n");
fail_noerr:
        free(data);
        ext4fs_root = NULL;

        return 0;
}