Add qemu 2.4.0
[kvmfornfv.git] / qemu / roms / u-boot / fs / ext4 / ext4_common.c
diff --git a/qemu/roms/u-boot/fs/ext4/ext4_common.c b/qemu/roms/u-boot/fs/ext4/ext4_common.c
new file mode 100644 (file)
index 0000000..1c11721
--- /dev/null
@@ -0,0 +1,2250 @@
+/*
+ * (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.
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <ext_common.h>
+#include <ext4fs.h>
+#include <malloc.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;
+uint32_t *ext4fs_indir1_block;
+int ext4fs_indir1_size;
+int ext4fs_indir1_blkno = -1;
+uint32_t *ext4fs_indir2_block;
+int ext4fs_indir2_size;
+int ext4fs_indir2_blkno = -1;
+
+uint32_t *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)
+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) {
+               if (fs->dev_desc->block_read) {
+                       fs->dev_desc->block_read(fs->dev_desc->dev,
+                                                startblock, 1, sec_buf);
+                       temp_ptr = sec_buf;
+                       memcpy((temp_ptr + remainder),
+                              (unsigned char *)buf, size);
+                       fs->dev_desc->block_write(fs->dev_desc->dev,
+                                                 startblock, 1, sec_buf);
+               }
+       } else {
+               if (size >> log2blksz != 0) {
+                       fs->dev_desc->block_write(fs->dev_desc->dev,
+                                                 startblock,
+                                                 size >> log2blksz,
+                                                 (unsigned long *)buf);
+               } else {
+                       fs->dev_desc->block_read(fs->dev_desc->dev,
+                                                startblock, 1, sec_buf);
+                       temp_ptr = sec_buf;
+                       memcpy(temp_ptr, buf, size);
+                       fs->dev_desc->block_write(fs->dev_desc->dev,
+                                                 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 > 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)
+{
+       unsigned char input;
+       int operand, status;
+       int count = 0;
+       int j = 0;
+       unsigned char *ptr = buffer;
+       struct ext_filesystem *fs = get_fs();
+
+       if (fs->blksz != 1024)
+               count = 0;
+       else
+               count = 1;
+
+       while (*ptr == 255) {
+               ptr++;
+               count += 8;
+               if (count == (fs->blksz * 8))
+                       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;
+}
+
+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 * 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 * 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);
+}
+
+int ext4fs_checksum_update(unsigned int i)
+{
+       struct ext2_block_group *desc;
+       struct ext_filesystem *fs = get_fs();
+       __u16 crc = 0;
+
+       desc = (struct ext2_block_group *)&fs->bgd[i];
+       if (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, &i, sizeof(i));
+               crc = ext2fs_crc16(crc, desc, offset);
+               offset += sizeof(desc->bg_checksum);    /* skip checksum */
+               assert(offset == sizeof(*desc));
+       }
+
+       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 = 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 = dentry_length;
+               return sizeof_void_space;
+       }
+
+       return 0;
+}
+
+void ext4fs_update_parent_dentry(char *filename, int *p_ino, int file_type)
+{
+       unsigned int *zero_buffer = NULL;
+       char *root_first_block_buffer = NULL;
+       int direct_blk_idx;
+       long int root_blknr;
+       long int first_block_no_of_root = 0;
+       long int previous_blknr = -1;
+       int totalbytes = 0;
+       short int padding_factor = 0;
+       unsigned int new_entry_byte_reqd;
+       unsigned int last_entry_dirlen;
+       int sizeof_void_space = 0;
+       int templength = 0;
+       int inodeno;
+       int status;
+       struct ext_filesystem *fs = get_fs();
+       /* directory entry */
+       struct ext2_dirent *dir;
+       char *temp_dir = NULL;
+
+       zero_buffer = zalloc(fs->blksz);
+       if (!zero_buffer) {
+               printf("No Memory\n");
+               return;
+       }
+       root_first_block_buffer = zalloc(fs->blksz);
+       if (!root_first_block_buffer) {
+               free(zero_buffer);
+               printf("No Memory\n");
+               return;
+       }
+restart:
+
+       /* read the block no allocated to a file */
+       for (direct_blk_idx = 0; direct_blk_idx < INDIRECT_BLOCKS;
+            direct_blk_idx++) {
+               root_blknr = read_allocated_block(g_parent_inode,
+                                                 direct_blk_idx);
+               if (root_blknr == 0) {
+                       first_block_no_of_root = previous_blknr;
+                       break;
+               }
+               previous_blknr = root_blknr;
+       }
+
+       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 (dir->direntlen > 0) {
+               /*
+                * blocksize-totalbytes because last directory length
+                * i.e. dir->direntlen is free availble space in the
+                * block that means  it is a last entry of directory
+                * entry
+                */
+
+               /* traversing the each directory entry */
+               if (fs->blksz - totalbytes == dir->direntlen) {
+                       if (strlen(filename) % 4 != 0)
+                               padding_factor = 4 - (strlen(filename) % 4);
+
+                       new_entry_byte_reqd = strlen(filename) +
+                           sizeof(struct ext2_dirent) + padding_factor;
+                       padding_factor = 0;
+                       /*
+                        * update last directory entry length to its
+                        * length because we are creating new directory
+                        * entry
+                        */
+                       if (dir->namelen % 4 != 0)
+                               padding_factor = 4 - (dir->namelen % 4);
+
+                       last_entry_dirlen = dir->namelen +
+                           sizeof(struct ext2_dirent) + padding_factor;
+                       if ((fs->blksz - totalbytes - last_entry_dirlen) <
+                               new_entry_byte_reqd) {
+                               printf("1st Block Full:Allocate new block\n");
+
+                               if (direct_blk_idx == INDIRECT_BLOCKS - 1) {
+                                       printf("Directory exceeds limit\n");
+                                       goto fail;
+                               }
+                               g_parent_inode->b.blocks.dir_blocks
+                                   [direct_blk_idx] = ext4fs_get_new_blk_no();
+                               if (g_parent_inode->b.blocks.dir_blocks
+                                       [direct_blk_idx] == -1) {
+                                       printf("no block left to assign\n");
+                                       goto fail;
+                               }
+                               put_ext4(((uint64_t)
+                                         ((uint64_t)g_parent_inode->b.
+                                          blocks.dir_blocks[direct_blk_idx] *
+                                          (uint64_t)fs->blksz)), zero_buffer, fs->blksz);
+                               g_parent_inode->size =
+                                   g_parent_inode->size + fs->blksz;
+                               g_parent_inode->blockcnt =
+                                   g_parent_inode->blockcnt + fs->sect_perblk;
+                               if (ext4fs_put_metadata
+                                   (root_first_block_buffer,
+                                    first_block_no_of_root))
+                                       goto fail;
+                               goto restart;
+                       }
+                       dir->direntlen = last_entry_dirlen;
+                       break;
+               }
+
+               templength = 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 = 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 = inodeno;
+       if (sizeof_void_space)
+               dir->direntlen = sizeof_void_space;
+       else
+               dir->direntlen = 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));
+
+       *p_ino = inodeno;
+
+       /* 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);
+}
+
+static int search_dir(struct ext2_inode *parent_inode, char *dirname)
+{
+       int status;
+       int inodeno;
+       int totalbytes;
+       int templength;
+       int direct_blk_idx;
+       long int blknr;
+       int found = 0;
+       char *ptr = NULL;
+       unsigned char *block_buffer = NULL;
+       struct ext2_dirent *dir = NULL;
+       struct ext2_dirent *previous_dir = NULL;
+       struct ext_filesystem *fs = get_fs();
+
+       /* read the block no allocated to a file */
+       for (direct_blk_idx = 0; direct_blk_idx < INDIRECT_BLOCKS;
+               direct_blk_idx++) {
+               blknr = read_allocated_block(parent_inode, direct_blk_idx);
+               if (blknr == 0)
+                       goto fail;
+
+               /* read the blocks of parenet inode */
+               block_buffer = zalloc(fs->blksz);
+               if (!block_buffer)
+                       goto fail;
+
+               status = ext4fs_devread((lbaint_t)blknr * fs->sect_perblk,
+                                       0, fs->blksz, (char *)block_buffer);
+               if (status == 0)
+                       goto fail;
+
+               dir = (struct ext2_dirent *)block_buffer;
+               ptr = (char *)dir;
+               totalbytes = 0;
+               while (dir->direntlen >= 0) {
+                       /*
+                        * blocksize-totalbytes because last directory
+                        * length i.e.,*dir->direntlen is free availble
+                        * space in the block that means
+                        * it is a last entry of directory entry
+                        */
+                       if (strlen(dirname) == dir->namelen) {
+                               if (strncmp(dirname, ptr +
+                                       sizeof(struct ext2_dirent),
+                                       dir->namelen) == 0) {
+                                       previous_dir->direntlen +=
+                                                       dir->direntlen;
+                                       inodeno = dir->inode;
+                                       dir->inode = 0;
+                                       found = 1;
+                                       break;
+                               }
+                       }
+
+                       if (fs->blksz - totalbytes == dir->direntlen)
+                               break;
+
+                       /* traversing the each directory entry */
+                       templength = dir->direntlen;
+                       totalbytes = totalbytes + templength;
+                       previous_dir = dir;
+                       dir = (struct ext2_dirent *)((char *)dir + templength);
+                       ptr = (char *)dir;
+               }
+
+               if (found == 1) {
+                       free(block_buffer);
+                       block_buffer = NULL;
+                       return inodeno;
+               }
+
+               free(block_buffer);
+               block_buffer = NULL;
+       }
+
+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;
+
+       arr[i++] = "/";
+
+       /* 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 (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);
+       free(ptr);
+       free(parent_inode);
+       free(first_inode);
+
+       return result_inode_no;
+}
+
+static int check_filename(char *filename, unsigned int blknr)
+{
+       unsigned int first_block_no_of_root;
+       int totalbytes = 0;
+       int templength = 0;
+       int status, inodeno;
+       int found = 0;
+       char *root_first_block_buffer = NULL;
+       char *root_first_block_addr = NULL;
+       struct ext2_dirent *dir = NULL;
+       struct ext2_dirent *previous_dir = NULL;
+       char *ptr = NULL;
+       struct ext_filesystem *fs = get_fs();
+
+       /* get the first block of root */
+       first_block_no_of_root = blknr;
+       root_first_block_buffer = zalloc(fs->blksz);
+       if (!root_first_block_buffer)
+               return -ENOMEM;
+       root_first_block_addr = root_first_block_buffer;
+       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;
+       ptr = (char *)dir;
+       totalbytes = 0;
+       while (dir->direntlen >= 0) {
+               /*
+                * blocksize-totalbytes because last
+                * directory length i.e., *dir->direntlen
+                * is free availble space in the block that
+                * means it is a last entry of directory entry
+                */
+               if (strlen(filename) == dir->namelen) {
+                       if (strncmp(filename, ptr + sizeof(struct ext2_dirent),
+                               dir->namelen) == 0) {
+                               printf("file found deleting\n");
+                               previous_dir->direntlen += dir->direntlen;
+                               inodeno = dir->inode;
+                               dir->inode = 0;
+                               found = 1;
+                               break;
+                       }
+               }
+
+               if (fs->blksz - totalbytes == dir->direntlen)
+                       break;
+
+               /* traversing the each directory entry */
+               templength = dir->direntlen;
+               totalbytes = totalbytes + templength;
+               previous_dir = dir;
+               dir = (struct ext2_dirent *)((char *)dir + templength);
+               ptr = (char *)dir;
+       }
+
+
+       if (found == 1) {
+               if (ext4fs_put_metadata(root_first_block_addr,
+                                       first_block_no_of_root))
+                       goto fail;
+               return inodeno;
+       }
+fail:
+       free(root_first_block_buffer);
+
+       return -1;
+}
+
+int ext4fs_filename_check(char *filename)
+{
+       short direct_blk_idx = 0;
+       long int blknr = -1;
+       int inodeno = -1;
+
+       /* read the block no allocated to a file */
+       for (direct_blk_idx = 0; direct_blk_idx < INDIRECT_BLOCKS;
+               direct_blk_idx++) {
+               blknr = read_allocated_block(g_parent_inode, direct_blk_idx);
+               if (blknr == 0)
+                       break;
+               inodeno = check_filename(filename, blknr);
+               if (inodeno != -1)
+                       return inodeno;
+       }
+
+       return -1;
+}
+
+long int 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 = 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;
+       struct ext2_block_group *bgd = (struct ext2_block_group *)fs->gdtable;
+
+       if (fs->first_pass_bbmap == 0) {
+               for (i = 0; i < fs->no_blkgrp; i++) {
+                       if (bgd[i].free_blocks) {
+                               if (bgd[i].bg_flags & EXT4_BG_BLOCK_UNINIT) {
+                                       put_ext4(((uint64_t) ((uint64_t)bgd[i].block_id *
+                                                             (uint64_t)fs->blksz)),
+                                                zero_buffer, fs->blksz);
+                                       bgd[i].bg_flags =
+                                           bgd[i].
+                                           bg_flags & ~EXT4_BG_BLOCK_UNINIT;
+                                       memcpy(fs->blk_bmaps[i], zero_buffer,
+                                              fs->blksz);
+                               }
+                               fs->curr_blkno =
+                                   _get_new_blk_no(fs->blk_bmaps[i]);
+                               if (fs->curr_blkno == -1)
+                                       /* if block bitmap is completely fill */
+                                       continue;
+                               fs->curr_blkno = fs->curr_blkno +
+                                               (i * fs->blksz * 8);
+                               fs->first_pass_bbmap++;
+                               bgd[i].free_blocks--;
+                               fs->sb->free_blocks--;
+                               status = ext4fs_devread((lbaint_t)
+                                                       bgd[i].block_id *
+                                                       fs->sect_perblk, 0,
+                                                       fs->blksz,
+                                                       journal_buffer);
+                               if (status == 0)
+                                       goto fail;
+                               if (ext4fs_log_journal(journal_buffer,
+                                                       bgd[i].block_id))
+                                       goto fail;
+                               goto success;
+                       } else {
+                               debug("no space left on block group %d\n", i);
+                       }
+               }
+
+               goto fail;
+       } else {
+restart:
+               fs->curr_blkno++;
+               /* 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;
+
+               if (bgd[bg_idx].free_blocks == 0) {
+                       debug("block group %u is full. Skipping\n", bg_idx);
+                       fs->curr_blkno = fs->curr_blkno + blk_per_grp;
+                       fs->curr_blkno--;
+                       goto restart;
+               }
+
+               if (bgd[bg_idx].bg_flags & EXT4_BG_BLOCK_UNINIT) {
+                       memset(zero_buffer, '\0', fs->blksz);
+                       put_ext4(((uint64_t) ((uint64_t)bgd[bg_idx].block_id *
+                                       (uint64_t)fs->blksz)), zero_buffer, fs->blksz);
+                       memcpy(fs->blk_bmaps[bg_idx], zero_buffer, fs->blksz);
+                       bgd[bg_idx].bg_flags = bgd[bg_idx].bg_flags &
+                                               ~EXT4_BG_BLOCK_UNINIT;
+               }
+
+               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);
+                       goto restart;
+               }
+
+               /* journal backup */
+               if (prev_bg_bitmap_index != bg_idx) {
+                       memset(journal_buffer, '\0', fs->blksz);
+                       status = ext4fs_devread((lbaint_t)bgd[bg_idx].block_id
+                                               * fs->sect_perblk,
+                                               0, fs->blksz, journal_buffer);
+                       if (status == 0)
+                               goto fail;
+                       if (ext4fs_log_journal(journal_buffer,
+                                               bgd[bg_idx].block_id))
+                               goto fail;
+
+                       prev_bg_bitmap_index = bg_idx;
+               }
+               bgd[bg_idx].free_blocks--;
+               fs->sb->free_blocks--;
+               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 = 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;
+       struct ext2_block_group *bgd = (struct ext2_block_group *)fs->gdtable;
+
+       if (fs->first_pass_ibmap == 0) {
+               for (i = 0; i < fs->no_blkgrp; i++) {
+                       if (bgd[i].free_inodes) {
+                               if (bgd[i].bg_itable_unused !=
+                                               bgd[i].free_inodes)
+                                       bgd[i].bg_itable_unused =
+                                               bgd[i].free_inodes;
+                               if (bgd[i].bg_flags & EXT4_BG_INODE_UNINIT) {
+                                       put_ext4(((uint64_t)
+                                                 ((uint64_t)bgd[i].inode_id *
+                                                       (uint64_t)fs->blksz)),
+                                                zero_buffer, fs->blksz);
+                                       bgd[i].bg_flags = bgd[i].bg_flags &
+                                                       ~EXT4_BG_INODE_UNINIT;
+                                       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)
+                                       /* if block bitmap is completely fill */
+                                       continue;
+                               fs->curr_inode_no = fs->curr_inode_no +
+                                                       (i * inodes_per_grp);
+                               fs->first_pass_ibmap++;
+                               bgd[i].free_inodes--;
+                               bgd[i].bg_itable_unused--;
+                               fs->sb->free_inodes--;
+                               status = ext4fs_devread((lbaint_t)
+                                                       bgd[i].inode_id *
+                                                       fs->sect_perblk, 0,
+                                                       fs->blksz,
+                                                       journal_buffer);
+                               if (status == 0)
+                                       goto fail;
+                               if (ext4fs_log_journal(journal_buffer,
+                                                       bgd[i].inode_id))
+                                       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;
+               if (bgd[ibmap_idx].bg_flags & EXT4_BG_INODE_UNINIT) {
+                       memset(zero_buffer, '\0', fs->blksz);
+                       put_ext4(((uint64_t) ((uint64_t)bgd[ibmap_idx].inode_id *
+                                             (uint64_t)fs->blksz)), zero_buffer,
+                                fs->blksz);
+                       bgd[ibmap_idx].bg_flags =
+                           bgd[ibmap_idx].bg_flags & ~EXT4_BG_INODE_UNINIT;
+                       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) {
+                       memset(journal_buffer, '\0', fs->blksz);
+                       status = ext4fs_devread((lbaint_t)
+                                               bgd[ibmap_idx].inode_id
+                                               * fs->sect_perblk,
+                                               0, fs->blksz, journal_buffer);
+                       if (status == 0)
+                               goto fail;
+                       if (ext4fs_log_journal(journal_buffer,
+                                               bgd[ibmap_idx].inode_id))
+                               goto fail;
+                       prev_inode_bitmap_index = ibmap_idx;
+               }
+               if (bgd[ibmap_idx].bg_itable_unused !=
+                               bgd[ibmap_idx].free_inodes)
+                       bgd[ibmap_idx].bg_itable_unused =
+                                       bgd[ibmap_idx].free_inodes;
+               bgd[ibmap_idx].free_inodes--;
+               bgd[ibmap_idx].bg_itable_unused--;
+               fs->sb->free_inodes--;
+               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 */
+       unsigned int *si_buffer = NULL;
+       unsigned int *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 = 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 = 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;
+       unsigned int *di_parent_buffer = NULL;
+       unsigned int *di_child_buff = NULL;
+       unsigned int *di_block_start_addr = NULL;
+       unsigned int *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 = 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 = 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 = 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;
+       unsigned int *ti_gp_buff = NULL;
+       unsigned int *ti_parent_buff = NULL;
+       unsigned int *ti_child_buff = NULL;
+       unsigned int *ti_gp_buff_start_addr = NULL;
+       unsigned int *ti_pbuff_start_addr = NULL;
+       unsigned int *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");
+                       goto fail;
+               }
+               ti_gp_buff = zalloc(fs->blksz);
+               if (!ti_gp_buff)
+                       goto fail;
+
+               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 = 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 fail;
+                               }
+                               ti_child_buff = zalloc(fs->blksz);
+                               if (!ti_child_buff)
+                                       goto fail;
+
+                               ti_cbuff_start_addr = ti_child_buff;
+                               *ti_parent_buff = 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");
+                                               goto fail;
+                                       }
+                                       *ti_child_buff = 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 = ti_gp_blockno;
+       }
+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; 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] = direct_blockno;
+               debug("DB %ld: %u\n", direct_blockno, total_remaining_blocks);
+
+               total_remaining_blocks--;
+               if (total_remaining_blocks == 0)
+                       break;
+       }
+
+       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 0;
+
+               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 0;
+
+               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 0;
+       }
+}
+
+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;
+
+       desc_per_blk = EXT2_BLOCK_SIZE(data) / sizeof(struct ext2_block_group);
+
+       blkno = __le32_to_cpu(data->sblock.first_data_block) + 1 +
+                       group / desc_per_blk;
+       blkoff = (group % desc_per_blk) * sizeof(struct ext2_block_group);
+
+       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, sizeof(struct ext2_block_group),
+                             (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 = __le32_to_cpu(blkgrp.inode_table_id) +
+           (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) {
+               char *buf = zalloc(blksz);
+               if (!buf)
+                       return -ENOMEM;
+               struct ext4_extent_header *ext_block;
+               struct ext4_extent *extent;
+               int i = -1;
+               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);
+
+               do {
+                       i++;
+                       if (i >= le16_to_cpu(ext_block->eh_entries))
+                               break;
+               } while (fileblock >= le32_to_cpu(extent[i].ee_block));
+               if (--i >= 0) {
+                       fileblock -= le32_to_cpu(extent[i].ee_block);
+                       if (fileblock >= le16_to_cpu(extent[i].ee_len)) {
+                               free(buf);
+                               return 0;
+                       }
+
+                       start = le16_to_cpu(extent[i].ee_start_hi);
+                       start = (start << 32) +
+                                       le32_to_cpu(extent[i].ee_start_lo);
+                       free(buf);
+                       return fileblock + start;
+               }
+
+               printf("Extent Error\n");
+               free(buf);
+               return -1;
+       }
+
+       /* 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 0;
+                       }
+                       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;
+       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);
+               if (status < 1)
+                       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);
+                       if (status < 1)
+                               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("%10d %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;
+
+       if (!diro->inode_read) {
+               status = ext4fs_read_inode(diro->data, diro->ino, &diro->inode);
+               if (status == 0)
+                       return 0;
+       }
+       symlink = zalloc(__le32_to_cpu(diro->inode.size) + 1);
+       if (!symlink)
+               return 0;
+
+       if (__le32_to_cpu(diro->inode.size) <= 60) {
+               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);
+               if (status == 0) {
+                       free(symlink);
+                       return 0;
+               }
+       }
+       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)
+{
+       struct ext2fs_node *fdiro = NULL;
+       int status;
+       int len;
+
+       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 len;
+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;
+
+       if (__le32_to_cpu(data->sblock.revision_level == 0))
+               fs->inodesz = 128;
+       else
+               fs->inodesz = __le16_to_cpu(data->sblock.inode_size);
+
+       debug("EXT2 rev %d, inode_size %d\n",
+              __le32_to_cpu(data->sblock.revision_level), fs->inodesz);
+
+       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");
+       free(data);
+       ext4fs_root = NULL;
+
+       return 0;
+}