ext4fs write support

Signed-off-by: Uma Shankar <uma.shankar@samsung.com>
Signed-off-by: Manjunatha C Achar <a.manjunatha@samsung.com>
Signed-off-by: Iqbal Shareef <iqbal.ams@samsung.com>
Signed-off-by: Hakgoo Lee <goodguy.lee@samsung.com>

8 files changed, 3226 insertions, 0 deletions

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 7b7fcbd9fda..82cd9ae16a5 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -34,6 +34,7 @@ COBJS-$(CONFIG_CMD_EXT4) := ext4fs.o ext4_common.o dev.o
 ifndef CONFIG_CMD_EXT4
 COBJS-$(CONFIG_CMD_EXT2) := ext4fs.o ext4_common.o dev.o
 endif
+COBJS-$(CONFIG_CMD_EXT4_WRITE) += ext4_journal.o crc16.o
 
 SRCS	:= $(AOBJS:.o=.S) $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(AOBJS) $(COBJS-y))
diff --git a/fs/ext4/crc16.c b/fs/ext4/crc16.c
new file mode 100644
index 00000000000..3afb34daefa
--- /dev/null
+++ b/fs/ext4/crc16.c
@@ -0,0 +1,62 @@
+/*
+ *      crc16.c
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <common.h>
+#include <asm/byteorder.h>
+#include <linux/stat.h>
+#include "crc16.h"
+
+/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 1) */
+static __u16 const crc16_table[256] = {
+	0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
+	0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
+	0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
+	0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
+	0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
+	0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
+	0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
+	0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
+	0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
+	0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
+	0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
+	0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
+	0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
+	0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
+	0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
+	0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
+	0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
+	0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
+	0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
+	0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
+	0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
+	0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
+	0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
+	0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
+	0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
+	0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
+	0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
+	0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
+	0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
+	0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
+	0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
+	0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
+};
+
+/**
+ * Compute the CRC-16 for the data buffer
+*/
+
+unsigned int ext2fs_crc16(unsigned int crc,
+	const void *buffer, unsigned int len)
+{
+	const unsigned char *cp = buffer;
+
+	while (len--)
+		crc = (((crc >> 8) & 0xffU) ^
+		       crc16_table[(crc ^ *cp++) & 0xffU]) & 0x0000ffffU;
+	return crc;
+}
diff --git a/fs/ext4/crc16.h b/fs/ext4/crc16.h
new file mode 100644
index 00000000000..5fd113a56c0
--- /dev/null
+++ b/fs/ext4/crc16.h
@@ -0,0 +1,16 @@
+/*
+ * crc16.h - CRC-16 routine
+ * Implements the standard CRC-16:
+ *  Width 16
+ *  Poly  0x8005 (x16 + x15 + x2 + 1)
+ *  Init  0
+ *
+ * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+#ifndef __CRC16_H
+#define __CRC16_H
+extern unsigned int ext2fs_crc16(unsigned int crc,
+	const void *buffer, unsigned int len);
+#endif
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 2ddbb50e890..083e45eed59 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -14,6 +14,8 @@
  * GRUB  --  GRand Unified Bootloader
  * Copyright (C) 2003, 2004  Free Software Foundation, Inc.
  *
+ * ext4write : Based on generic ext4 protocol.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
@@ -54,6 +56,1357 @@ int ext4fs_indir3_blkno = -1;
 struct ext2_inode *g_parent_inode;
 static int symlinknest;
 
+#if defined(CONFIG_CMD_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;
+	unsigned char sec_buf[SECTOR_SIZE];
+	struct ext_filesystem *fs = get_fs();
+
+	startblock = off / (uint64_t)SECTOR_SIZE;
+	startblock += part_offset;
+	remainder = off % (uint64_t)SECTOR_SIZE;
+	remainder &= SECTOR_SIZE - 1;
+
+	if (fs->dev_desc == NULL)
+		return;
+
+	if ((startblock + (size / SECTOR_SIZE)) >
+	    (part_offset + fs->total_sect)) {
+		printf("part_offset is %lu\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 / SECTOR_SIZE != 0) {
+			fs->dev_desc->block_write(fs->dev_desc->dev,
+						  startblock,
+						  size / SECTOR_SIZE,
+						  (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->gd[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 *ptr = NULL;
+	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(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
+		 */
+
+		/* 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)
+					  (g_parent_inode->b.
+					   blocks.dir_blocks[direct_blk_idx] *
+					   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);
+		ptr = (char *)dir;
+	}
+
+	/* make a pointer ready for creating next directory entry */
+	templength = dir->direntlen;
+	totalbytes = totalbytes + templength;
+	dir = (struct ext2_dirent *)((char *)dir + templength);
+	ptr = (char *)dir;
+
+	/* 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(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(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 *gd = (struct ext2_block_group *)fs->gdtable;
+
+	if (fs->first_pass_bbmap == 0) {
+		for (i = 0; i < fs->no_blkgrp; i++) {
+			if (gd[i].free_blocks) {
+				if (gd[i].bg_flags & EXT4_BG_BLOCK_UNINIT) {
+					put_ext4(((uint64_t) (gd[i].block_id *
+							      fs->blksz)),
+						 zero_buffer, fs->blksz);
+					gd[i].bg_flags =
+					    gd[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++;
+				gd[i].free_blocks--;
+				fs->sb->free_blocks--;
+				status = ext4fs_devread(gd[i].block_id *
+							fs->sect_perblk, 0,
+							fs->blksz,
+							journal_buffer);
+				if (status == 0)
+					goto fail;
+				if (ext4fs_log_journal(journal_buffer,
+							gd[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 */
+		if (fs->blksz != 1024) {
+			bg_idx = fs->curr_blkno / blk_per_grp;
+		} else {
+			bg_idx = fs->curr_blkno / blk_per_grp;
+			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 (gd[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 (gd[bg_idx].bg_flags & EXT4_BG_BLOCK_UNINIT) {
+			memset(zero_buffer, '\0', fs->blksz);
+			put_ext4(((uint64_t) (gd[bg_idx].block_id * fs->blksz)),
+				 zero_buffer, fs->blksz);
+			memcpy(fs->blk_bmaps[bg_idx], zero_buffer, fs->blksz);
+			gd[bg_idx].bg_flags = gd[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(gd[bg_idx].block_id
+						* fs->sect_perblk,
+						0, fs->blksz, journal_buffer);
+			if (status == 0)
+				goto fail;
+			if (ext4fs_log_journal(journal_buffer,
+						gd[bg_idx].block_id))
+				goto fail;
+
+			prev_bg_bitmap_index = bg_idx;
+		}
+		gd[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 *gd = (struct ext2_block_group *)fs->gdtable;
+
+	if (fs->first_pass_ibmap == 0) {
+		for (i = 0; i < fs->no_blkgrp; i++) {
+			if (gd[i].free_inodes) {
+				if (gd[i].bg_itable_unused != gd[i].free_inodes)
+					gd[i].bg_itable_unused =
+						gd[i].free_inodes;
+				if (gd[i].bg_flags & EXT4_BG_INODE_UNINIT) {
+					put_ext4(((uint64_t)
+						  (gd[i].inode_id * fs->blksz)),
+						 zero_buffer, fs->blksz);
+					gd[i].bg_flags = gd[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++;
+				gd[i].free_inodes--;
+				gd[i].bg_itable_unused--;
+				fs->sb->free_inodes--;
+				status = ext4fs_devread(gd[i].inode_id *
+							fs->sect_perblk, 0,
+							fs->blksz,
+							journal_buffer);
+				if (status == 0)
+					goto fail;
+				if (ext4fs_log_journal(journal_buffer,
+							gd[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 (gd[ibmap_idx].bg_flags & EXT4_BG_INODE_UNINIT) {
+			memset(zero_buffer, '\0', fs->blksz);
+			put_ext4(((uint64_t) (gd[ibmap_idx].inode_id *
+					      fs->blksz)), zero_buffer,
+				 fs->blksz);
+			gd[ibmap_idx].bg_flags =
+			    gd[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(gd[ibmap_idx].inode_id
+						* fs->sect_perblk,
+						0, fs->blksz, journal_buffer);
+			if (status == 0)
+				goto fail;
+			if (ext4fs_log_journal(journal_buffer,
+						gd[ibmap_idx].inode_id))
+				goto fail;
+			prev_inode_bitmap_index = ibmap_idx;
+		}
+		if (gd[ibmap_idx].bg_itable_unused != gd[ibmap_idx].free_inodes)
+			gd[ibmap_idx].bg_itable_unused =
+					gd[ibmap_idx].free_inodes;
+		gd[ibmap_idx].free_inodes--;
+		gd[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(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) (si_blockno * 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(di_blockno_parent *
+					fs->sect_perblk, 0,
+					fs->blksz, (char *)di_parent_buffer);
+		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(di_blockno_child *
+						fs->sect_perblk, 0,
+						fs->blksz,
+						(char *)di_child_buff);
+			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) (di_blockno_child * 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) (di_blockno_parent * 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) (ti_child_blockno *
+						      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) (ti_parent_blockno * 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) (ti_gp_blockno * 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,
diff --git a/fs/ext4/ext4_common.h b/fs/ext4/ext4_common.h
index 8e8bcbc0fa7..801b8b848ad 100644
--- a/fs/ext4/ext4_common.h
+++ b/fs/ext4/ext4_common.h
@@ -14,6 +14,8 @@
  * GRUB  --  GRand Unified Bootloader
  * Copyright (C) 2003, 2004  Free Software Foundation, Inc.
  *
+ * ext4write : Based on generic ext4 protocol.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
@@ -35,6 +37,10 @@
 #include <ext4fs.h>
 #include <malloc.h>
 #include <asm/errno.h>
+#if defined(CONFIG_CMD_EXT4_WRITE)
+#include "ext4_journal.h"
+#include "crc16.h"
+#endif
 
 #define YES		1
 #define NO		0
@@ -60,4 +66,23 @@ int ext4fs_find_file(const char *path, struct ext2fs_node *rootnode,
 			struct ext2fs_node **foundnode, int expecttype);
 int ext4fs_iterate_dir(struct ext2fs_node *dir, char *name,
 			struct ext2fs_node **fnode, int *ftype);
+
+#if defined(CONFIG_CMD_EXT4_WRITE)
+uint32_t ext4fs_div_roundup(uint32_t size, uint32_t n);
+int ext4fs_checksum_update(unsigned int i);
+int ext4fs_get_parent_inode_num(const char *dirname, char *dname, int flags);
+void ext4fs_update_parent_dentry(char *filename, int *p_ino, int file_type);
+long int ext4fs_get_new_blk_no(void);
+int ext4fs_get_new_inode_no(void);
+void ext4fs_reset_block_bmap(long int blockno, unsigned char *buffer,
+					int index);
+int ext4fs_set_block_bmap(long int blockno, unsigned char *buffer, int index);
+int ext4fs_set_inode_bmap(int inode_no, unsigned char *buffer, int index);
+void ext4fs_reset_inode_bmap(int inode_no, unsigned char *buffer, int index);
+int ext4fs_iget(int inode_no, struct ext2_inode *inode);
+void ext4fs_allocate_blocks(struct ext2_inode *file_inode,
+				unsigned int total_remaining_blocks,
+				unsigned int *total_no_of_block);
+void put_ext4(uint64_t off, void *buf, uint32_t size);
+#endif
 #endif
diff --git a/fs/ext4/ext4_journal.c b/fs/ext4/ext4_journal.c
new file mode 100644
index 00000000000..8a252d66c33
--- /dev/null
+++ b/fs/ext4/ext4_journal.c
@@ -0,0 +1,667 @@
+/*
+ * (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>
+ *
+ * Journal data structures and headers for Journaling feature of ext4
+ * have been referred from JBD2 (Journaling Block device 2)
+ * implementation in Linux Kernel.
+ * Written by Stephen C. Tweedie <sct@redhat.com>
+ *
+ * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <common.h>
+#include <ext4fs.h>
+#include <malloc.h>
+#include <ext_common.h>
+#include "ext4_common.h"
+
+static struct revoke_blk_list *revk_blk_list;
+static struct revoke_blk_list *prev_node;
+static int first_node = TRUE;
+
+int gindex;
+int gd_index;
+int jrnl_blk_idx;
+struct journal_log *journal_ptr[MAX_JOURNAL_ENTRIES];
+struct dirty_blocks *dirty_block_ptr[MAX_JOURNAL_ENTRIES];
+
+int ext4fs_init_journal(void)
+{
+	int i;
+	char *temp = NULL;
+	struct ext_filesystem *fs = get_fs();
+
+	/* init globals */
+	revk_blk_list = NULL;
+	prev_node = NULL;
+	gindex = 0;
+	gd_index = 0;
+	jrnl_blk_idx = 1;
+
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		journal_ptr[i] = zalloc(sizeof(struct journal_log));
+		if (!journal_ptr[i])
+			goto fail;
+		dirty_block_ptr[i] = zalloc(sizeof(struct dirty_blocks));
+		if (!dirty_block_ptr[i])
+			goto fail;
+		journal_ptr[i]->buf = NULL;
+		journal_ptr[i]->blknr = -1;
+
+		dirty_block_ptr[i]->buf = NULL;
+		dirty_block_ptr[i]->blknr = -1;
+	}
+
+	if (fs->blksz == 4096) {
+		temp = zalloc(fs->blksz);
+		if (!temp)
+			goto fail;
+		journal_ptr[gindex]->buf = zalloc(fs->blksz);
+		if (!journal_ptr[gindex]->buf)
+			goto fail;
+		ext4fs_devread(0, 0, fs->blksz, temp);
+		memcpy(temp + SUPERBLOCK_SIZE, fs->sb, SUPERBLOCK_SIZE);
+		memcpy(journal_ptr[gindex]->buf, temp, fs->blksz);
+		journal_ptr[gindex++]->blknr = 0;
+		free(temp);
+	} else {
+		journal_ptr[gindex]->buf = zalloc(fs->blksz);
+		if (!journal_ptr[gindex]->buf)
+			goto fail;
+		memcpy(journal_ptr[gindex]->buf, fs->sb, SUPERBLOCK_SIZE);
+		journal_ptr[gindex++]->blknr = 1;
+	}
+
+	/* Check the file system state using journal super block */
+	if (ext4fs_check_journal_state(SCAN))
+		goto fail;
+	/* Check the file system state using journal super block */
+	if (ext4fs_check_journal_state(RECOVER))
+		goto fail;
+
+	return 0;
+fail:
+	return -1;
+}
+
+void ext4fs_dump_metadata(void)
+{
+	struct ext_filesystem *fs = get_fs();
+	int i;
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (dirty_block_ptr[i]->blknr == -1)
+			break;
+		put_ext4((uint64_t) ((uint64_t)dirty_block_ptr[i]->blknr *
+				(uint64_t)fs->blksz), dirty_block_ptr[i]->buf,
+								fs->blksz);
+	}
+}
+
+void ext4fs_free_journal(void)
+{
+	int i;
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (dirty_block_ptr[i]->blknr == -1)
+			break;
+		if (dirty_block_ptr[i]->buf)
+			free(dirty_block_ptr[i]->buf);
+	}
+
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (journal_ptr[i]->blknr == -1)
+			break;
+		if (journal_ptr[i]->buf)
+			free(journal_ptr[i]->buf);
+	}
+
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (journal_ptr[i])
+			free(journal_ptr[i]);
+		if (dirty_block_ptr[i])
+			free(dirty_block_ptr[i]);
+	}
+	gindex = 0;
+	gd_index = 0;
+	jrnl_blk_idx = 1;
+}
+
+int ext4fs_log_gdt(char *gd_table)
+{
+	struct ext_filesystem *fs = get_fs();
+	short i;
+	long int var = fs->gdtable_blkno;
+	for (i = 0; i < fs->no_blk_pergdt; i++) {
+		journal_ptr[gindex]->buf = zalloc(fs->blksz);
+		if (!journal_ptr[gindex]->buf)
+			return -ENOMEM;
+		memcpy(journal_ptr[gindex]->buf, gd_table, fs->blksz);
+		gd_table += fs->blksz;
+		journal_ptr[gindex++]->blknr = var++;
+	}
+
+	return 0;
+}
+
+/*
+ * This function stores the backup copy of meta data in RAM
+ * journal_buffer -- Buffer containing meta data
+ * blknr -- Block number on disk of the meta data buffer
+ */
+int ext4fs_log_journal(char *journal_buffer, long int blknr)
+{
+	struct ext_filesystem *fs = get_fs();
+	short i;
+
+	if (!journal_buffer) {
+		printf("Invalid input arguments %s\n", __func__);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (journal_ptr[i]->blknr == -1)
+			break;
+		if (journal_ptr[i]->blknr == blknr)
+			return 0;
+	}
+
+	journal_ptr[gindex]->buf = zalloc(fs->blksz);
+	if (!journal_ptr[gindex]->buf)
+		return -ENOMEM;
+
+	memcpy(journal_ptr[gindex]->buf, journal_buffer, fs->blksz);
+	journal_ptr[gindex++]->blknr = blknr;
+
+	return 0;
+}
+
+/*
+ * This function stores the modified meta data in RAM
+ * metadata_buffer -- Buffer containing meta data
+ * blknr -- Block number on disk of the meta data buffer
+ */
+int ext4fs_put_metadata(char *metadata_buffer, long int blknr)
+{
+	struct ext_filesystem *fs = get_fs();
+	if (!metadata_buffer) {
+		printf("Invalid input arguments %s\n", __func__);
+		return -EINVAL;
+	}
+	dirty_block_ptr[gd_index]->buf = zalloc(fs->blksz);
+	if (!dirty_block_ptr[gd_index]->buf)
+		return -ENOMEM;
+	memcpy(dirty_block_ptr[gd_index]->buf, metadata_buffer, fs->blksz);
+	dirty_block_ptr[gd_index++]->blknr = blknr;
+
+	return 0;
+}
+
+void print_revoke_blks(char *revk_blk)
+{
+	int offset;
+	int max;
+	long int blocknr;
+	struct journal_revoke_header_t *header;
+
+	if (revk_blk == NULL)
+		return;
+
+	header = (struct journal_revoke_header_t *) revk_blk;
+	offset = sizeof(struct journal_revoke_header_t);
+	max = be32_to_cpu(header->r_count);
+	printf("total bytes %d\n", max);
+
+	while (offset < max) {
+		blocknr = be32_to_cpu(*((long int *)(revk_blk + offset)));
+		printf("revoke blknr is %ld\n", blocknr);
+		offset += 4;
+	}
+}
+
+static struct revoke_blk_list *_get_node(void)
+{
+	struct revoke_blk_list *tmp_node;
+	tmp_node = zalloc(sizeof(struct revoke_blk_list));
+	if (tmp_node == NULL)
+		return NULL;
+	tmp_node->content = NULL;
+	tmp_node->next = NULL;
+
+	return tmp_node;
+}
+
+void ext4fs_push_revoke_blk(char *buffer)
+{
+	struct revoke_blk_list *node = NULL;
+	struct ext_filesystem *fs = get_fs();
+	if (buffer == NULL) {
+		printf("buffer ptr is NULL\n");
+		return;
+	}
+	node = _get_node();
+	if (!node) {
+		printf("_get_node: malloc failed\n");
+		return;
+	}
+
+	node->content = zalloc(fs->blksz);
+	if (node->content == NULL)
+		return;
+	memcpy(node->content, buffer, fs->blksz);
+
+	if (first_node == TRUE) {
+		revk_blk_list = node;
+		prev_node = node;
+		 first_node = FALSE;
+	} else {
+		prev_node->next = node;
+		prev_node = node;
+	}
+}
+
+void ext4fs_free_revoke_blks(void)
+{
+	struct revoke_blk_list *tmp_node = revk_blk_list;
+	struct revoke_blk_list *next_node = NULL;
+
+	while (tmp_node != NULL) {
+		if (tmp_node->content)
+			free(tmp_node->content);
+		tmp_node = tmp_node->next;
+	}
+
+	tmp_node = revk_blk_list;
+	while (tmp_node != NULL) {
+		next_node = tmp_node->next;
+		free(tmp_node);
+		tmp_node = next_node;
+	}
+
+	revk_blk_list = NULL;
+	prev_node = NULL;
+	first_node = TRUE;
+}
+
+int check_blknr_for_revoke(long int blknr, int sequence_no)
+{
+	struct journal_revoke_header_t *header;
+	int offset;
+	int max;
+	long int blocknr;
+	char *revk_blk;
+	struct revoke_blk_list *tmp_revk_node = revk_blk_list;
+	while (tmp_revk_node != NULL) {
+		revk_blk = tmp_revk_node->content;
+
+		header = (struct journal_revoke_header_t *) revk_blk;
+		if (sequence_no < be32_to_cpu(header->r_header.h_sequence)) {
+			offset = sizeof(struct journal_revoke_header_t);
+			max = be32_to_cpu(header->r_count);
+
+			while (offset < max) {
+				blocknr = be32_to_cpu(*((long int *)
+						  (revk_blk + offset)));
+				if (blocknr == blknr)
+					goto found;
+				offset += 4;
+			}
+		}
+		tmp_revk_node = tmp_revk_node->next;
+	}
+
+	return -1;
+
+found:
+	return 0;
+}
+
+/*
+ * This function parses the journal blocks and replays the
+ * suceessful transactions. A transaction is successfull
+ * if commit block is found for a descriptor block
+ * The tags in descriptor block contain the disk block
+ * numbers of the metadata  to be replayed
+ */
+void recover_transaction(int prev_desc_logical_no)
+{
+	struct ext2_inode inode_journal;
+	struct ext_filesystem *fs = get_fs();
+	struct journal_header_t *jdb;
+	long int blknr;
+	char *p_jdb;
+	int ofs, flags;
+	int i;
+	struct ext3_journal_block_tag *tag;
+	char *temp_buff = zalloc(fs->blksz);
+	char *metadata_buff = zalloc(fs->blksz);
+	if (!temp_buff || !metadata_buff)
+		goto fail;
+	i = prev_desc_logical_no;
+	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO,
+			  (struct ext2_inode *)&inode_journal);
+	blknr = read_allocated_block((struct ext2_inode *)
+				     &inode_journal, i);
+	ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
+	p_jdb = (char *)temp_buff;
+	jdb = (struct journal_header_t *) temp_buff;
+	ofs = sizeof(struct journal_header_t);
+
+	do {
+		tag = (struct ext3_journal_block_tag *)&p_jdb[ofs];
+		ofs += sizeof(struct ext3_journal_block_tag);
+
+		if (ofs > fs->blksz)
+			break;
+
+		flags = be32_to_cpu(tag->flags);
+		if (!(flags & EXT3_JOURNAL_FLAG_SAME_UUID))
+			ofs += 16;
+
+		i++;
+		debug("\t\ttag %u\n", be32_to_cpu(tag->block));
+		if (revk_blk_list != NULL) {
+			if (check_blknr_for_revoke(be32_to_cpu(tag->block),
+				be32_to_cpu(jdb->h_sequence)) == 0)
+				continue;
+		}
+		blknr = read_allocated_block(&inode_journal, i);
+		ext4fs_devread(blknr * fs->sect_perblk, 0,
+			       fs->blksz, metadata_buff);
+		put_ext4((uint64_t)(be32_to_cpu(tag->block) * fs->blksz),
+			 metadata_buff, (uint32_t) fs->blksz);
+	} while (!(flags & EXT3_JOURNAL_FLAG_LAST_TAG));
+fail:
+	free(temp_buff);
+	free(metadata_buff);
+}
+
+void print_jrnl_status(int recovery_flag)
+{
+	if (recovery_flag == RECOVER)
+		printf("Journal Recovery Completed\n");
+	else
+		printf("Journal Scan Completed\n");
+}
+
+int ext4fs_check_journal_state(int recovery_flag)
+{
+	int i;
+	int DB_FOUND = NO;
+	long int blknr;
+	int transaction_state = TRANSACTION_COMPLETE;
+	int prev_desc_logical_no = 0;
+	int curr_desc_logical_no = 0;
+	int ofs, flags, block;
+	struct ext2_inode inode_journal;
+	struct journal_superblock_t *jsb = NULL;
+	struct journal_header_t *jdb = NULL;
+	char *p_jdb = NULL;
+	struct ext3_journal_block_tag *tag = NULL;
+	char *temp_buff = NULL;
+	char *temp_buff1 = NULL;
+	struct ext_filesystem *fs = get_fs();
+
+	temp_buff = zalloc(fs->blksz);
+	if (!temp_buff)
+		return -ENOMEM;
+	temp_buff1 = zalloc(fs->blksz);
+	if (!temp_buff1) {
+		free(temp_buff);
+		return -ENOMEM;
+	}
+
+	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
+	blknr = read_allocated_block(&inode_journal, EXT2_JOURNAL_SUPERBLOCK);
+	ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
+	jsb = (struct journal_superblock_t *) temp_buff;
+
+	if (fs->sb->feature_incompat & EXT3_FEATURE_INCOMPAT_RECOVER) {
+		if (recovery_flag == RECOVER)
+			printf("Recovery required\n");
+	} else {
+		if (recovery_flag == RECOVER)
+			printf("File System is consistent\n");
+		goto end;
+	}
+
+	if (be32_to_cpu(jsb->s_start) == 0)
+		goto end;
+
+	if (!(jsb->s_feature_compat &
+				cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM)))
+		jsb->s_feature_compat |=
+				cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
+
+	i = be32_to_cpu(jsb->s_first);
+	while (1) {
+		block = be32_to_cpu(jsb->s_first);
+		blknr = read_allocated_block(&inode_journal, i);
+		memset(temp_buff1, '\0', fs->blksz);
+		ext4fs_devread(blknr * fs->sect_perblk,
+			       0, fs->blksz, temp_buff1);
+		jdb = (struct journal_header_t *) temp_buff1;
+
+		if (be32_to_cpu(jdb->h_blocktype) ==
+		    EXT3_JOURNAL_DESCRIPTOR_BLOCK) {
+			if (be32_to_cpu(jdb->h_sequence) !=
+			    be32_to_cpu(jsb->s_sequence)) {
+				print_jrnl_status(recovery_flag);
+				break;
+			}
+
+			curr_desc_logical_no = i;
+			if (transaction_state == TRANSACTION_COMPLETE)
+				transaction_state = TRANSACTION_RUNNING;
+			else
+				return -1;
+			p_jdb = (char *)temp_buff1;
+			ofs = sizeof(struct journal_header_t);
+			do {
+				tag = (struct ext3_journal_block_tag *)
+				    &p_jdb[ofs];
+				ofs += sizeof(struct ext3_journal_block_tag);
+				if (ofs > fs->blksz)
+					break;
+				flags = be32_to_cpu(tag->flags);
+				if (!(flags & EXT3_JOURNAL_FLAG_SAME_UUID))
+					ofs += 16;
+				i++;
+				debug("\t\ttag %u\n", be32_to_cpu(tag->block));
+			} while (!(flags & EXT3_JOURNAL_FLAG_LAST_TAG));
+			i++;
+			DB_FOUND = YES;
+		} else if (be32_to_cpu(jdb->h_blocktype) ==
+				EXT3_JOURNAL_COMMIT_BLOCK) {
+			if (be32_to_cpu(jdb->h_sequence) !=
+			     be32_to_cpu(jsb->s_sequence)) {
+				print_jrnl_status(recovery_flag);
+				break;
+			}
+
+			if (transaction_state == TRANSACTION_RUNNING ||
+					(DB_FOUND == NO)) {
+				transaction_state = TRANSACTION_COMPLETE;
+				i++;
+				jsb->s_sequence =
+					cpu_to_be32(be32_to_cpu(
+						jsb->s_sequence) + 1);
+			}
+			prev_desc_logical_no = curr_desc_logical_no;
+			if ((recovery_flag == RECOVER) && (DB_FOUND == YES))
+				recover_transaction(prev_desc_logical_no);
+
+			DB_FOUND = NO;
+		} else if (be32_to_cpu(jdb->h_blocktype) ==
+				EXT3_JOURNAL_REVOKE_BLOCK) {
+			if (be32_to_cpu(jdb->h_sequence) !=
+			    be32_to_cpu(jsb->s_sequence)) {
+				print_jrnl_status(recovery_flag);
+				break;
+			}
+			if (recovery_flag == SCAN)
+				ext4fs_push_revoke_blk((char *)jdb);
+			i++;
+		} else {
+			debug("Else Case\n");
+			if (be32_to_cpu(jdb->h_sequence) !=
+			    be32_to_cpu(jsb->s_sequence)) {
+				print_jrnl_status(recovery_flag);
+				break;
+			}
+		}
+	}
+
+end:
+	if (recovery_flag == RECOVER) {
+		jsb->s_start = cpu_to_be32(1);
+		jsb->s_sequence = cpu_to_be32(be32_to_cpu(jsb->s_sequence) + 1);
+		/* get the superblock */
+		ext4fs_devread(SUPERBLOCK_SECTOR, 0, SUPERBLOCK_SIZE,
+			       (char *)fs->sb);
+		fs->sb->feature_incompat |= EXT3_FEATURE_INCOMPAT_RECOVER;
+
+		/* Update the super block */
+		put_ext4((uint64_t) (SUPERBLOCK_SIZE),
+			 (struct ext2_sblock *)fs->sb,
+			 (uint32_t) SUPERBLOCK_SIZE);
+		ext4fs_devread(SUPERBLOCK_SECTOR, 0, SUPERBLOCK_SIZE,
+			       (char *)fs->sb);
+
+		blknr = read_allocated_block(&inode_journal,
+					 EXT2_JOURNAL_SUPERBLOCK);
+		put_ext4((uint64_t) (blknr * fs->blksz),
+			 (struct journal_superblock_t *)temp_buff,
+			 (uint32_t) fs->blksz);
+		ext4fs_free_revoke_blks();
+	}
+	free(temp_buff);
+	free(temp_buff1);
+
+	return 0;
+}
+
+static void update_descriptor_block(long int blknr)
+{
+	int i;
+	long int jsb_blknr;
+	struct journal_header_t jdb;
+	struct ext3_journal_block_tag tag;
+	struct ext2_inode inode_journal;
+	struct journal_superblock_t *jsb = NULL;
+	char *buf = NULL;
+	char *temp = NULL;
+	struct ext_filesystem *fs = get_fs();
+	char *temp_buff = zalloc(fs->blksz);
+	if (!temp_buff)
+		return;
+
+	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
+	jsb_blknr = read_allocated_block(&inode_journal,
+					 EXT2_JOURNAL_SUPERBLOCK);
+	ext4fs_devread(jsb_blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
+	jsb = (struct journal_superblock_t *) temp_buff;
+
+	jdb.h_blocktype = cpu_to_be32(EXT3_JOURNAL_DESCRIPTOR_BLOCK);
+	jdb.h_magic = cpu_to_be32(EXT3_JOURNAL_MAGIC_NUMBER);
+	jdb.h_sequence = jsb->s_sequence;
+	buf = zalloc(fs->blksz);
+	if (!buf) {
+		free(temp_buff);
+		return;
+	}
+	temp = buf;
+	memcpy(buf, &jdb, sizeof(struct journal_header_t));
+	temp += sizeof(struct journal_header_t);
+
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (journal_ptr[i]->blknr == -1)
+			break;
+
+		tag.block = cpu_to_be32(journal_ptr[i]->blknr);
+		tag.flags = cpu_to_be32(EXT3_JOURNAL_FLAG_SAME_UUID);
+		memcpy(temp, &tag, sizeof(struct ext3_journal_block_tag));
+		temp = temp + sizeof(struct ext3_journal_block_tag);
+	}
+
+	tag.block = cpu_to_be32(journal_ptr[--i]->blknr);
+	tag.flags = cpu_to_be32(EXT3_JOURNAL_FLAG_LAST_TAG);
+	memcpy(temp - sizeof(struct ext3_journal_block_tag), &tag,
+	       sizeof(struct ext3_journal_block_tag));
+	put_ext4((uint64_t) (blknr * fs->blksz), buf, (uint32_t) fs->blksz);
+
+	free(temp_buff);
+	free(buf);
+}
+
+static void update_commit_block(long int blknr)
+{
+	struct journal_header_t jdb;
+	struct ext_filesystem *fs = get_fs();
+	char *buf = NULL;
+	struct ext2_inode inode_journal;
+	struct journal_superblock_t *jsb;
+	long int jsb_blknr;
+	char *temp_buff = zalloc(fs->blksz);
+	if (!temp_buff)
+		return;
+
+	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
+	jsb_blknr = read_allocated_block(&inode_journal,
+					 EXT2_JOURNAL_SUPERBLOCK);
+	ext4fs_devread(jsb_blknr * fs->sect_perblk, 0, fs->blksz, temp_buff);
+	jsb = (struct journal_superblock_t *) temp_buff;
+
+	jdb.h_blocktype = cpu_to_be32(EXT3_JOURNAL_COMMIT_BLOCK);
+	jdb.h_magic = cpu_to_be32(EXT3_JOURNAL_MAGIC_NUMBER);
+	jdb.h_sequence = jsb->s_sequence;
+	buf = zalloc(fs->blksz);
+	if (!buf) {
+		free(temp_buff);
+		return;
+	}
+	memcpy(buf, &jdb, sizeof(struct journal_header_t));
+	put_ext4((uint64_t) (blknr * fs->blksz), buf, (uint32_t) fs->blksz);
+
+	free(temp_buff);
+	free(buf);
+}
+
+void ext4fs_update_journal(void)
+{
+	struct ext2_inode inode_journal;
+	struct ext_filesystem *fs = get_fs();
+	long int blknr;
+	int i;
+	ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO, &inode_journal);
+	blknr = read_allocated_block(&inode_journal, jrnl_blk_idx++);
+	update_descriptor_block(blknr);
+	for (i = 0; i < MAX_JOURNAL_ENTRIES; i++) {
+		if (journal_ptr[i]->blknr == -1)
+			break;
+		blknr = read_allocated_block(&inode_journal, jrnl_blk_idx++);
+		put_ext4((uint64_t) ((uint64_t)blknr * (uint64_t)fs->blksz),
+			 journal_ptr[i]->buf, fs->blksz);
+	}
+	blknr = read_allocated_block(&inode_journal, jrnl_blk_idx++);
+	update_commit_block(blknr);
+	printf("update journal finished\n");
+}
diff --git a/fs/ext4/ext4_journal.h b/fs/ext4/ext4_journal.h
new file mode 100644
index 00000000000..acc1c51635b
--- /dev/null
+++ b/fs/ext4/ext4_journal.h
@@ -0,0 +1,141 @@
+/*
+ * (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>
+ *
+ * Journal data structures and headers for Journaling feature of ext4
+ * have been referred from JBD2 (Journaling Block device 2)
+ * implementation in Linux Kernel.
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>
+ *
+ * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef __EXT4_JRNL__
+#define __EXT4_JRNL__
+
+#define EXT2_JOURNAL_INO		8	/* Journal inode */
+#define EXT2_JOURNAL_SUPERBLOCK	0	/* Journal  Superblock number */
+
+#define JBD2_FEATURE_COMPAT_CHECKSUM	0x00000001
+#define EXT3_JOURNAL_MAGIC_NUMBER	0xc03b3998U
+#define TRANSACTION_RUNNING		1
+#define TRANSACTION_COMPLETE		0
+#define EXT3_FEATURE_INCOMPAT_RECOVER	0x0004	/* Needs recovery */
+#define EXT3_JOURNAL_DESCRIPTOR_BLOCK	1
+#define EXT3_JOURNAL_COMMIT_BLOCK	2
+#define EXT3_JOURNAL_SUPERBLOCK_V1	3
+#define EXT3_JOURNAL_SUPERBLOCK_V2	4
+#define EXT3_JOURNAL_REVOKE_BLOCK	5
+#define EXT3_JOURNAL_FLAG_ESCAPE	1
+#define EXT3_JOURNAL_FLAG_SAME_UUID	2
+#define EXT3_JOURNAL_FLAG_DELETED	4
+#define EXT3_JOURNAL_FLAG_LAST_TAG	8
+
+/* Maximum entries in 1 journal transaction */
+#define MAX_JOURNAL_ENTRIES 100
+struct journal_log {
+	char *buf;
+	int blknr;
+};
+
+struct dirty_blocks {
+	char *buf;
+	int blknr;
+};
+
+/* Standard header for all descriptor blocks: */
+struct journal_header_t {
+	__u32 h_magic;
+	__u32 h_blocktype;
+	__u32 h_sequence;
+};
+
+/* The journal superblock.  All fields are in big-endian byte order. */
+struct journal_superblock_t {
+	/* 0x0000 */
+	struct journal_header_t s_header;
+
+	/* Static information describing the journal */
+	__u32 s_blocksize;	/* journal device blocksize */
+	__u32 s_maxlen;		/* total blocks in journal file */
+	__u32 s_first;		/* first block of log information */
+
+	/* Dynamic information describing the current state of the log */
+	__u32 s_sequence;	/* first commit ID expected in log */
+	__u32 s_start;		/* blocknr of start of log */
+
+	/* Error value, as set by journal_abort(). */
+	__s32 s_errno;
+
+	/* Remaining fields are only valid in a version-2 superblock */
+	__u32 s_feature_compat;	/* compatible feature set */
+	__u32 s_feature_incompat;	/* incompatible feature set */
+	__u32 s_feature_ro_compat;	/* readonly-compatible feature set */
+	/* 0x0030 */
+	__u8 s_uuid[16];	/* 128-bit uuid for journal */
+
+	/* 0x0040 */
+	__u32 s_nr_users;	/* Nr of filesystems sharing log */
+
+	__u32 s_dynsuper;	/* Blocknr of dynamic superblock copy */
+
+	/* 0x0048 */
+	__u32 s_max_transaction;	/* Limit of journal blocks per trans. */
+	__u32 s_max_trans_data;	/* Limit of data blocks per trans. */
+
+	/* 0x0050 */
+	__u32 s_padding[44];
+
+	/* 0x0100 */
+	__u8 s_users[16 * 48];	/* ids of all fs'es sharing the log */
+	/* 0x0400 */
+} ;
+
+struct ext3_journal_block_tag {
+	uint32_t block;
+	uint32_t flags;
+};
+
+struct journal_revoke_header_t {
+	struct journal_header_t r_header;
+	int r_count;		/* Count of bytes used in the block */
+};
+
+struct revoke_blk_list {
+	char *content;		/* revoke block itself */
+	struct revoke_blk_list *next;
+};
+
+extern struct ext2_data *ext4fs_root;
+
+int ext4fs_init_journal(void);
+int ext4fs_log_gdt(char *gd_table);
+int ext4fs_check_journal_state(int recovery_flag);
+int ext4fs_log_journal(char *journal_buffer, long int blknr);
+int ext4fs_put_metadata(char *metadata_buffer, long int blknr);
+void ext4fs_update_journal(void);
+void ext4fs_dump_metadata(void);
+void ext4fs_push_revoke_blk(char *buffer);
+void ext4fs_free_journal(void);
+void ext4fs_free_revoke_blks(void);
+#endif
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index 1287bf0e182..114c2a21498 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -16,6 +16,8 @@
  * GRUB  --  GRand Unified Bootloader
  * Copyright (C) 2003, 2004  Free Software Foundation, Inc.
  *
+ * ext4write : Based on generic ext4 protocol.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
@@ -226,3 +228,962 @@ int ext4fs_read(char *buf, unsigned len)
 
 	return ext4fs_read_file(ext4fs_file, 0, len, buf);
 }
+
+#if defined(CONFIG_CMD_EXT4_WRITE)
+static void ext4fs_update(void)
+{
+	short i;
+	ext4fs_update_journal();
+	struct ext_filesystem *fs = get_fs();
+
+	/* update  super block */
+	put_ext4((uint64_t)(SUPERBLOCK_SIZE),
+		 (struct ext2_sblock *)fs->sb, (uint32_t)SUPERBLOCK_SIZE);
+
+	/* update block groups */
+	for (i = 0; i < fs->no_blkgrp; i++) {
+		fs->gd[i].bg_checksum = ext4fs_checksum_update(i);
+		put_ext4((uint64_t)(fs->gd[i].block_id * fs->blksz),
+			 fs->blk_bmaps[i], fs->blksz);
+	}
+
+	/* update inode table groups */
+	for (i = 0; i < fs->no_blkgrp; i++) {
+		put_ext4((uint64_t) (fs->gd[i].inode_id * fs->blksz),
+			 fs->inode_bmaps[i], fs->blksz);
+	}
+
+	/* update the block group descriptor table */
+	put_ext4((uint64_t)(fs->gdtable_blkno * fs->blksz),
+		 (struct ext2_block_group *)fs->gdtable,
+		 (fs->blksz * fs->no_blk_pergdt));
+
+	ext4fs_dump_metadata();
+
+	gindex = 0;
+	gd_index = 0;
+}
+
+int ext4fs_get_bgdtable(void)
+{
+	int status;
+	int grp_desc_size;
+	struct ext_filesystem *fs = get_fs();
+	grp_desc_size = sizeof(struct ext2_block_group);
+	fs->no_blk_pergdt = (fs->no_blkgrp * grp_desc_size) / fs->blksz;
+	if ((fs->no_blkgrp * grp_desc_size) % fs->blksz)
+		fs->no_blk_pergdt++;
+
+	/* allocate memory for gdtable */
+	fs->gdtable = zalloc(fs->blksz * fs->no_blk_pergdt);
+	if (!fs->gdtable)
+		return -ENOMEM;
+	/* read the group descriptor table */
+	status = ext4fs_devread(fs->gdtable_blkno * fs->sect_perblk, 0,
+				fs->blksz * fs->no_blk_pergdt, fs->gdtable);
+	if (status == 0)
+		goto fail;
+
+	if (ext4fs_log_gdt(fs->gdtable)) {
+		printf("Error in ext4fs_log_gdt\n");
+		return -1;
+	}
+
+	return 0;
+fail:
+	free(fs->gdtable);
+	fs->gdtable = NULL;
+
+	return -1;
+}
+
+static void delete_single_indirect_block(struct ext2_inode *inode)
+{
+	struct ext2_block_group *gd = NULL;
+	static int prev_bg_bmap_idx = -1;
+	long int blknr;
+	int remainder;
+	int bg_idx;
+	int status;
+	unsigned int blk_per_grp = ext4fs_root->sblock.blocks_per_group;
+	struct ext_filesystem *fs = get_fs();
+	char *journal_buffer = zalloc(fs->blksz);
+	if (!journal_buffer) {
+		printf("No memory\n");
+		return;
+	}
+	/* get  block group descriptor table */
+	gd = (struct ext2_block_group *)fs->gdtable;
+
+	/* deleting the single indirect block associated with inode */
+	if (inode->b.blocks.indir_block != 0) {
+		debug("SIPB releasing %u\n", inode->b.blocks.indir_block);
+		blknr = inode->b.blocks.indir_block;
+		if (fs->blksz != 1024) {
+			bg_idx = blknr / blk_per_grp;
+		} else {
+			bg_idx = blknr / blk_per_grp;
+			remainder = blknr % blk_per_grp;
+			if (!remainder)
+				bg_idx--;
+		}
+		ext4fs_reset_block_bmap(blknr, fs->blk_bmaps[bg_idx], bg_idx);
+		gd[bg_idx].free_blocks++;
+		fs->sb->free_blocks++;
+		/* journal backup */
+		if (prev_bg_bmap_idx != bg_idx) {
+			status =
+			    ext4fs_devread(gd[bg_idx].block_id *
+					   fs->sect_perblk, 0, fs->blksz,
+					   journal_buffer);
+			if (status == 0)
+				goto fail;
+			if (ext4fs_log_journal
+			    (journal_buffer, gd[bg_idx].block_id))
+				goto fail;
+			prev_bg_bmap_idx = bg_idx;
+		}
+	}
+fail:
+	free(journal_buffer);
+}
+
+static void delete_double_indirect_block(struct ext2_inode *inode)
+{
+	int i;
+	short status;
+	static int prev_bg_bmap_idx = -1;
+	long int blknr;
+	int remainder;
+	int bg_idx;
+	unsigned int blk_per_grp = ext4fs_root->sblock.blocks_per_group;
+	unsigned int *di_buffer = NULL;
+	unsigned int *DIB_start_addr = NULL;
+	struct ext2_block_group *gd = NULL;
+	struct ext_filesystem *fs = get_fs();
+	char *journal_buffer = zalloc(fs->blksz);
+	if (!journal_buffer) {
+		printf("No memory\n");
+		return;
+	}
+	/* get the block group descriptor table */
+	gd = (struct ext2_block_group *)fs->gdtable;
+
+	if (inode->b.blocks.double_indir_block != 0) {
+		di_buffer = zalloc(fs->blksz);
+		if (!di_buffer) {
+			printf("No memory\n");
+			return;
+		}
+		DIB_start_addr = (unsigned int *)di_buffer;
+		blknr = inode->b.blocks.double_indir_block;
+		status = ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz,
+					(char *)di_buffer);
+		for (i = 0; i < fs->blksz / sizeof(int); i++) {
+			if (*di_buffer == 0)
+				break;
+
+			debug("DICB releasing %u\n", *di_buffer);
+			if (fs->blksz != 1024) {
+				bg_idx = (*di_buffer) / blk_per_grp;
+			} else {
+				bg_idx = (*di_buffer) / blk_per_grp;
+				remainder = (*di_buffer) % blk_per_grp;
+				if (!remainder)
+					bg_idx--;
+			}
+			ext4fs_reset_block_bmap(*di_buffer,
+					fs->blk_bmaps[bg_idx], bg_idx);
+			di_buffer++;
+			gd[bg_idx].free_blocks++;
+			fs->sb->free_blocks++;
+			/* journal backup */
+			if (prev_bg_bmap_idx != bg_idx) {
+				status = ext4fs_devread(gd[bg_idx].block_id
+							* fs->sect_perblk, 0,
+							fs->blksz,
+							journal_buffer);
+				if (status == 0)
+					goto fail;
+
+				if (ext4fs_log_journal(journal_buffer,
+							gd[bg_idx].block_id))
+					goto fail;
+				prev_bg_bmap_idx = bg_idx;
+			}
+		}
+
+		/* removing the parent double indirect block */
+		blknr = inode->b.blocks.double_indir_block;
+		if (fs->blksz != 1024) {
+			bg_idx = blknr / blk_per_grp;
+		} else {
+			bg_idx = blknr / blk_per_grp;
+			remainder = blknr % blk_per_grp;
+			if (!remainder)
+				bg_idx--;
+		}
+		ext4fs_reset_block_bmap(blknr, fs->blk_bmaps[bg_idx], bg_idx);
+		gd[bg_idx].free_blocks++;
+		fs->sb->free_blocks++;
+		/* journal backup */
+		if (prev_bg_bmap_idx != bg_idx) {
+			memset(journal_buffer, '\0', fs->blksz);
+			status = ext4fs_devread(gd[bg_idx].block_id *
+						fs->sect_perblk, 0, fs->blksz,
+						journal_buffer);
+			if (status == 0)
+				goto fail;
+
+			if (ext4fs_log_journal(journal_buffer,
+						gd[bg_idx].block_id))
+				goto fail;
+			prev_bg_bmap_idx = bg_idx;
+		}
+		debug("DIPB releasing %ld\n", blknr);
+	}
+fail:
+	free(DIB_start_addr);
+	free(journal_buffer);
+}
+
+static void delete_triple_indirect_block(struct ext2_inode *inode)
+{
+	int i, j;
+	short status;
+	static int prev_bg_bmap_idx = -1;
+	long int blknr;
+	int remainder;
+	int bg_idx;
+	unsigned int blk_per_grp = ext4fs_root->sblock.blocks_per_group;
+	unsigned int *tigp_buffer = NULL;
+	unsigned int *tib_start_addr = NULL;
+	unsigned int *tip_buffer = NULL;
+	unsigned int *tipb_start_addr = NULL;
+	struct ext2_block_group *gd = NULL;
+	struct ext_filesystem *fs = get_fs();
+	char *journal_buffer = zalloc(fs->blksz);
+	if (!journal_buffer) {
+		printf("No memory\n");
+		return;
+	}
+	/* get block group descriptor table */
+	gd = (struct ext2_block_group *)fs->gdtable;
+
+	if (inode->b.blocks.triple_indir_block != 0) {
+		tigp_buffer = zalloc(fs->blksz);
+		if (!tigp_buffer) {
+			printf("No memory\n");
+			return;
+		}
+		tib_start_addr = (unsigned int *)tigp_buffer;
+		blknr = inode->b.blocks.triple_indir_block;
+		status = ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz,
+					(char *)tigp_buffer);
+		for (i = 0; i < fs->blksz / sizeof(int); i++) {
+			if (*tigp_buffer == 0)
+				break;
+			debug("tigp buffer releasing %u\n", *tigp_buffer);
+
+			tip_buffer = zalloc(fs->blksz);
+			if (!tip_buffer)
+				goto fail;
+			tipb_start_addr = (unsigned int *)tip_buffer;
+			status = ext4fs_devread((*tigp_buffer) *
+						fs->sect_perblk, 0, fs->blksz,
+						(char *)tip_buffer);
+			for (j = 0; j < fs->blksz / sizeof(int); j++) {
+				if (*tip_buffer == 0)
+					break;
+				if (fs->blksz != 1024) {
+					bg_idx = (*tip_buffer) / blk_per_grp;
+				} else {
+					bg_idx = (*tip_buffer) / blk_per_grp;
+
+					remainder = (*tip_buffer) % blk_per_grp;
+					if (!remainder)
+						bg_idx--;
+				}
+
+				ext4fs_reset_block_bmap(*tip_buffer,
+							fs->blk_bmaps[bg_idx],
+							bg_idx);
+
+				tip_buffer++;
+				gd[bg_idx].free_blocks++;
+				fs->sb->free_blocks++;
+				/* journal backup */
+				if (prev_bg_bmap_idx != bg_idx) {
+					status =
+					    ext4fs_devread(gd[bg_idx].block_id *
+							   fs->sect_perblk, 0,
+							   fs->blksz,
+							   journal_buffer);
+					if (status == 0)
+						goto fail;
+
+					if (ext4fs_log_journal(journal_buffer,
+							       gd[bg_idx].
+							       block_id))
+						goto fail;
+					prev_bg_bmap_idx = bg_idx;
+				}
+			}
+			free(tipb_start_addr);
+			tipb_start_addr = NULL;
+
+			/*
+			 * removing the grand parent blocks
+			 * which is connected to inode
+			 */
+			if (fs->blksz != 1024) {
+				bg_idx = (*tigp_buffer) / blk_per_grp;
+			} else {
+				bg_idx = (*tigp_buffer) / blk_per_grp;
+
+				remainder = (*tigp_buffer) % blk_per_grp;
+				if (!remainder)
+					bg_idx--;
+			}
+			ext4fs_reset_block_bmap(*tigp_buffer,
+						fs->blk_bmaps[bg_idx], bg_idx);
+
+			tigp_buffer++;
+			gd[bg_idx].free_blocks++;
+			fs->sb->free_blocks++;
+			/* journal backup */
+			if (prev_bg_bmap_idx != bg_idx) {
+				memset(journal_buffer, '\0', fs->blksz);
+				status =
+				    ext4fs_devread(gd[bg_idx].block_id *
+						   fs->sect_perblk, 0,
+						   fs->blksz, journal_buffer);
+				if (status == 0)
+					goto fail;
+
+				if (ext4fs_log_journal(journal_buffer,
+							gd[bg_idx].block_id))
+					goto fail;
+				prev_bg_bmap_idx = bg_idx;
+			}
+		}
+
+		/* removing the grand parent triple indirect block */
+		blknr = inode->b.blocks.triple_indir_block;
+		if (fs->blksz != 1024) {
+			bg_idx = blknr / blk_per_grp;
+		} else {
+			bg_idx = blknr / blk_per_grp;
+			remainder = blknr % blk_per_grp;
+			if (!remainder)
+				bg_idx--;
+		}
+		ext4fs_reset_block_bmap(blknr, fs->blk_bmaps[bg_idx], bg_idx);
+		gd[bg_idx].free_blocks++;
+		fs->sb->free_blocks++;
+		/* journal backup */
+		if (prev_bg_bmap_idx != bg_idx) {
+			memset(journal_buffer, '\0', fs->blksz);
+			status = ext4fs_devread(gd[bg_idx].block_id *
+						fs->sect_perblk, 0, fs->blksz,
+						journal_buffer);
+			if (status == 0)
+				goto fail;
+
+			if (ext4fs_log_journal(journal_buffer,
+						gd[bg_idx].block_id))
+				goto fail;
+			prev_bg_bmap_idx = bg_idx;
+		}
+		debug("tigp buffer itself releasing %ld\n", blknr);
+	}
+fail:
+	free(tib_start_addr);
+	free(tipb_start_addr);
+	free(journal_buffer);
+}
+
+static int ext4fs_delete_file(int inodeno)
+{
+	struct ext2_inode inode;
+	short status;
+	int i;
+	int remainder;
+	long int blknr;
+	int bg_idx;
+	int ibmap_idx;
+	char *read_buffer = NULL;
+	char *start_block_address = NULL;
+	unsigned int no_blocks;
+
+	static int prev_bg_bmap_idx = -1;
+	unsigned int inodes_per_block;
+	long int blkno;
+	unsigned int blkoff;
+	unsigned int blk_per_grp = ext4fs_root->sblock.blocks_per_group;
+	unsigned int inode_per_grp = ext4fs_root->sblock.inodes_per_group;
+	struct ext2_inode *inode_buffer = NULL;
+	struct ext2_block_group *gd = NULL;
+	struct ext_filesystem *fs = get_fs();
+	char *journal_buffer = zalloc(fs->blksz);
+	if (!journal_buffer)
+		return -ENOMEM;
+	/* get the block group descriptor table */
+	gd = (struct ext2_block_group *)fs->gdtable;
+	status = ext4fs_read_inode(ext4fs_root, inodeno, &inode);
+	if (status == 0)
+		goto fail;
+
+	/* read the block no allocated to a file */
+	no_blocks = inode.size / fs->blksz;
+	if (inode.size % fs->blksz)
+		no_blocks++;
+
+	if (le32_to_cpu(inode.flags) & EXT4_EXTENTS_FL) {
+		struct ext2fs_node *node_inode =
+		    zalloc(sizeof(struct ext2fs_node));
+		if (!node_inode)
+			goto fail;
+		node_inode->data = ext4fs_root;
+		node_inode->ino = inodeno;
+		node_inode->inode_read = 0;
+		memcpy(&(node_inode->inode), &inode, sizeof(struct ext2_inode));
+
+		for (i = 0; i < no_blocks; i++) {
+			blknr = read_allocated_block(&(node_inode->inode), i);
+			if (fs->blksz != 1024) {
+				bg_idx = blknr / blk_per_grp;
+			} else {
+				bg_idx = blknr / blk_per_grp;
+				remainder = blknr % blk_per_grp;
+				if (!remainder)
+					bg_idx--;
+			}
+			ext4fs_reset_block_bmap(blknr, fs->blk_bmaps[bg_idx],
+						bg_idx);
+			debug("EXT4_EXTENTS Block releasing %ld: %d\n",
+			      blknr, bg_idx);
+
+			gd[bg_idx].free_blocks++;
+			fs->sb->free_blocks++;
+
+			/* journal backup */
+			if (prev_bg_bmap_idx != bg_idx) {
+				status =
+				    ext4fs_devread(gd[bg_idx].block_id *
+						   fs->sect_perblk, 0,
+						   fs->blksz, journal_buffer);
+				if (status == 0)
+					goto fail;
+				if (ext4fs_log_journal(journal_buffer,
+							gd[bg_idx].block_id))
+					goto fail;
+				prev_bg_bmap_idx = bg_idx;
+			}
+		}
+		if (node_inode) {
+			free(node_inode);
+			node_inode = NULL;
+		}
+	} else {
+
+		delete_single_indirect_block(&inode);
+		delete_double_indirect_block(&inode);
+		delete_triple_indirect_block(&inode);
+
+		/* read the block no allocated to a file */
+		no_blocks = inode.size / fs->blksz;
+		if (inode.size % fs->blksz)
+			no_blocks++;
+		for (i = 0; i < no_blocks; i++) {
+			blknr = read_allocated_block(&inode, i);
+			if (fs->blksz != 1024) {
+				bg_idx = blknr / blk_per_grp;
+			} else {
+				bg_idx = blknr / blk_per_grp;
+				remainder = blknr % blk_per_grp;
+				if (!remainder)
+					bg_idx--;
+			}
+			ext4fs_reset_block_bmap(blknr, fs->blk_bmaps[bg_idx],
+						bg_idx);
+			debug("ActualB releasing %ld: %d\n", blknr, bg_idx);
+
+			gd[bg_idx].free_blocks++;
+			fs->sb->free_blocks++;
+			/* journal backup */
+			if (prev_bg_bmap_idx != bg_idx) {
+				memset(journal_buffer, '\0', fs->blksz);
+				status = ext4fs_devread(gd[bg_idx].block_id
+							* fs->sect_perblk,
+							0, fs->blksz,
+							journal_buffer);
+				if (status == 0)
+					goto fail;
+				if (ext4fs_log_journal(journal_buffer,
+						gd[bg_idx].block_id))
+					goto fail;
+				prev_bg_bmap_idx = bg_idx;
+			}
+		}
+	}
+
+	/* from the inode no to blockno */
+	inodes_per_block = fs->blksz / fs->inodesz;
+	ibmap_idx = inodeno / inode_per_grp;
+
+	/* get the block no */
+	inodeno--;
+	blkno = __le32_to_cpu(gd[ibmap_idx].inode_table_id) +
+		(inodeno % __le32_to_cpu(inode_per_grp)) / inodes_per_block;
+
+	/* get the offset of the inode */
+	blkoff = ((inodeno) % inodes_per_block) * fs->inodesz;
+
+	/* read the block no containing the inode */
+	read_buffer = zalloc(fs->blksz);
+	if (!read_buffer)
+		goto fail;
+	start_block_address = read_buffer;
+	status = ext4fs_devread(blkno * fs->sect_perblk,
+				0, fs->blksz, read_buffer);
+	if (status == 0)
+		goto fail;
+
+	if (ext4fs_log_journal(read_buffer, blkno))
+		goto fail;
+
+	read_buffer = read_buffer + blkoff;
+	inode_buffer = (struct ext2_inode *)read_buffer;
+	memset(inode_buffer, '\0', sizeof(struct ext2_inode));
+
+	/* write the inode to original position in inode table */
+	if (ext4fs_put_metadata(start_block_address, blkno))
+		goto fail;
+
+	/* update the respective inode bitmaps */
+	inodeno++;
+	ext4fs_reset_inode_bmap(inodeno, fs->inode_bmaps[ibmap_idx], ibmap_idx);
+	gd[ibmap_idx].free_inodes++;
+	fs->sb->free_inodes++;
+	/* journal backup */
+	memset(journal_buffer, '\0', fs->blksz);
+	status = ext4fs_devread(gd[ibmap_idx].inode_id *
+				fs->sect_perblk, 0, fs->blksz, journal_buffer);
+	if (status == 0)
+		goto fail;
+	if (ext4fs_log_journal(journal_buffer, gd[ibmap_idx].inode_id))
+		goto fail;
+
+	ext4fs_update();
+	ext4fs_deinit();
+
+	if (ext4fs_init() != 0) {
+		printf("error in File System init\n");
+		goto fail;
+	}
+
+	free(start_block_address);
+	free(journal_buffer);
+
+	return 0;
+fail:
+	free(start_block_address);
+	free(journal_buffer);
+
+	return -1;
+}
+
+int ext4fs_init(void)
+{
+	short status;
+	int i;
+	unsigned int real_free_blocks = 0;
+	struct ext_filesystem *fs = get_fs();
+
+	/* populate fs */
+	fs->blksz = EXT2_BLOCK_SIZE(ext4fs_root);
+	fs->inodesz = INODE_SIZE_FILESYSTEM(ext4fs_root);
+	fs->sect_perblk = fs->blksz / SECTOR_SIZE;
+
+	/* get the superblock */
+	fs->sb = zalloc(SUPERBLOCK_SIZE);
+	if (!fs->sb)
+		return -ENOMEM;
+	if (!ext4fs_devread(SUPERBLOCK_SECTOR, 0, SUPERBLOCK_SIZE,
+			(char *)fs->sb))
+		goto fail;
+
+	/* init journal */
+	if (ext4fs_init_journal())
+		goto fail;
+
+	/* get total no of blockgroups */
+	fs->no_blkgrp = (uint32_t)ext4fs_div_roundup(
+			(ext4fs_root->sblock.total_blocks -
+			ext4fs_root->sblock.first_data_block),
+			ext4fs_root->sblock.blocks_per_group);
+
+	/* get the block group descriptor table */
+	fs->gdtable_blkno = ((EXT2_MIN_BLOCK_SIZE == fs->blksz) + 1);
+	if (ext4fs_get_bgdtable() == -1) {
+		printf("Error in getting the block group descriptor table\n");
+		goto fail;
+	}
+	fs->gd = (struct ext2_block_group *)fs->gdtable;
+
+	/* load all the available bitmap block of the partition */
+	fs->blk_bmaps = zalloc(fs->no_blkgrp * sizeof(char *));
+	if (!fs->blk_bmaps)
+		goto fail;
+	for (i = 0; i < fs->no_blkgrp; i++) {
+		fs->blk_bmaps[i] = zalloc(fs->blksz);
+		if (!fs->blk_bmaps[i])
+			goto fail;
+	}
+
+	for (i = 0; i < fs->no_blkgrp; i++) {
+		status =
+		    ext4fs_devread(fs->gd[i].block_id * fs->sect_perblk, 0,
+				   fs->blksz, (char *)fs->blk_bmaps[i]);
+		if (status == 0)
+			goto fail;
+	}
+
+	/* load all the available inode bitmap of the partition */
+	fs->inode_bmaps = zalloc(fs->no_blkgrp * sizeof(unsigned char *));
+	if (!fs->inode_bmaps)
+		goto fail;
+	for (i = 0; i < fs->no_blkgrp; i++) {
+		fs->inode_bmaps[i] = zalloc(fs->blksz);
+		if (!fs->inode_bmaps[i])
+			goto fail;
+	}
+
+	for (i = 0; i < fs->no_blkgrp; i++) {
+		status = ext4fs_devread(fs->gd[i].inode_id * fs->sect_perblk,
+					0, fs->blksz,
+					(char *)fs->inode_bmaps[i]);
+		if (status == 0)
+			goto fail;
+	}
+
+	/*
+	 * check filesystem consistency with free blocks of file system
+	 * some time we observed that superblock freeblocks does not match
+	 * with the  blockgroups freeblocks when improper
+	 * reboot of a linux kernel
+	 */
+	for (i = 0; i < fs->no_blkgrp; i++)
+		real_free_blocks = real_free_blocks + fs->gd[i].free_blocks;
+	if (real_free_blocks != fs->sb->free_blocks)
+		fs->sb->free_blocks = real_free_blocks;
+
+	return 0;
+fail:
+	ext4fs_deinit();
+
+	return -1;
+}
+
+void ext4fs_deinit(void)
+{
+	int i;
+	struct ext2_inode inode_journal;
+	struct journal_superblock_t *jsb;
+	long int blknr;
+	struct ext_filesystem *fs = get_fs();
+
+	/* free journal */
+	char *temp_buff = zalloc(fs->blksz);
+	if (temp_buff) {
+		ext4fs_read_inode(ext4fs_root, EXT2_JOURNAL_INO,
+				  &inode_journal);
+		blknr = read_allocated_block(&inode_journal,
+					EXT2_JOURNAL_SUPERBLOCK);
+		ext4fs_devread(blknr * fs->sect_perblk, 0, fs->blksz,
+			       temp_buff);
+		jsb = (struct journal_superblock_t *)temp_buff;
+		jsb->s_start = cpu_to_be32(0);
+		put_ext4((uint64_t) (blknr * fs->blksz),
+			 (struct journal_superblock_t *)temp_buff, fs->blksz);
+		free(temp_buff);
+	}
+	ext4fs_free_journal();
+
+	/* get the superblock */
+	ext4fs_devread(SUPERBLOCK_SECTOR, 0, SUPERBLOCK_SIZE, (char *)fs->sb);
+	fs->sb->feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;
+	put_ext4((uint64_t)(SUPERBLOCK_SIZE),
+		 (struct ext2_sblock *)fs->sb, (uint32_t)SUPERBLOCK_SIZE);
+	free(fs->sb);
+	fs->sb = NULL;
+
+	if (fs->blk_bmaps) {
+		for (i = 0; i < fs->no_blkgrp; i++) {
+			free(fs->blk_bmaps[i]);
+			fs->blk_bmaps[i] = NULL;
+		}
+		free(fs->blk_bmaps);
+		fs->blk_bmaps = NULL;
+	}
+
+	if (fs->inode_bmaps) {
+		for (i = 0; i < fs->no_blkgrp; i++) {
+			free(fs->inode_bmaps[i]);
+			fs->inode_bmaps[i] = NULL;
+		}
+		free(fs->inode_bmaps);
+		fs->inode_bmaps = NULL;
+	}
+
+
+	free(fs->gdtable);
+	fs->gdtable = NULL;
+	fs->gd = NULL;
+	/*
+	 * reinitiliazed the global inode and
+	 * block bitmap first execution check variables
+	 */
+	fs->first_pass_ibmap = 0;
+	fs->first_pass_bbmap = 0;
+	fs->curr_inode_no = 0;
+	fs->curr_blkno = 0;
+}
+
+static int ext4fs_write_file(struct ext2_inode *file_inode,
+			     int pos, unsigned int len, char *buf)
+{
+	int i;
+	int blockcnt;
+	int log2blocksize = LOG2_EXT2_BLOCK_SIZE(ext4fs_root);
+	unsigned int filesize = __le32_to_cpu(file_inode->size);
+	struct ext_filesystem *fs = get_fs();
+	int previous_block_number = -1;
+	int delayed_start = 0;
+	int delayed_extent = 0;
+	int delayed_skipfirst = 0;
+	int delayed_next = 0;
+	char *delayed_buf = NULL;
+
+	/* Adjust len so it we can't read past the end of the file. */
+	if (len > filesize)
+		len = filesize;
+
+	blockcnt = ((len + pos) + fs->blksz - 1) / fs->blksz;
+
+	for (i = pos / fs->blksz; i < blockcnt; i++) {
+		long int blknr;
+		int blockend = fs->blksz;
+		int skipfirst = 0;
+		blknr = read_allocated_block(file_inode, i);
+		if (blknr < 0)
+			return -1;
+
+		blknr = blknr << log2blocksize;
+
+		if (blknr) {
+			if (previous_block_number != -1) {
+				if (delayed_next == blknr) {
+					delayed_extent += blockend;
+					delayed_next += blockend >> SECTOR_BITS;
+				} else {	/* spill */
+					put_ext4((uint64_t) (delayed_start *
+							     SECTOR_SIZE),
+						 delayed_buf,
+						 (uint32_t) delayed_extent);
+					previous_block_number = blknr;
+					delayed_start = blknr;
+					delayed_extent = blockend;
+					delayed_skipfirst = skipfirst;
+					delayed_buf = buf;
+					delayed_next = blknr +
+					    (blockend >> SECTOR_BITS);
+				}
+			} else {
+				previous_block_number = blknr;
+				delayed_start = blknr;
+				delayed_extent = blockend;
+				delayed_skipfirst = skipfirst;
+				delayed_buf = buf;
+				delayed_next = blknr +
+				    (blockend >> SECTOR_BITS);
+			}
+		} else {
+			if (previous_block_number != -1) {
+				/* spill */
+				put_ext4((uint64_t) (delayed_start *
+						     SECTOR_SIZE), delayed_buf,
+					 (uint32_t) delayed_extent);
+				previous_block_number = -1;
+			}
+			memset(buf, 0, fs->blksz - skipfirst);
+		}
+		buf += fs->blksz - skipfirst;
+	}
+	if (previous_block_number != -1) {
+		/* spill */
+		put_ext4((uint64_t) (delayed_start * SECTOR_SIZE),
+			 delayed_buf, (uint32_t) delayed_extent);
+		previous_block_number = -1;
+	}
+
+	return len;
+}
+
+int ext4fs_write(const char *fname, unsigned char *buffer,
+					unsigned long sizebytes)
+{
+	int ret = 0;
+	struct ext2_inode *file_inode = NULL;
+	unsigned char *inode_buffer = NULL;
+	int parent_inodeno;
+	int inodeno;
+	time_t timestamp = 0;
+
+	uint64_t bytes_reqd_for_file;
+	unsigned int blks_reqd_for_file;
+	unsigned int blocks_remaining;
+	int existing_file_inodeno;
+	char filename[256];
+
+	char *temp_ptr = NULL;
+	long int itable_blkno;
+	long int parent_itable_blkno;
+	long int blkoff;
+	struct ext2_sblock *sblock = &(ext4fs_root->sblock);
+	unsigned int inodes_per_block;
+	unsigned int ibmap_idx;
+	struct ext_filesystem *fs = get_fs();
+	g_parent_inode = zalloc(sizeof(struct ext2_inode));
+	if (!g_parent_inode)
+		goto fail;
+
+	if (ext4fs_init() != 0) {
+		printf("error in File System init\n");
+		return -1;
+	}
+	inodes_per_block = fs->blksz / fs->inodesz;
+	parent_inodeno = ext4fs_get_parent_inode_num(fname, filename, F_FILE);
+	if (parent_inodeno == -1)
+		goto fail;
+	if (ext4fs_iget(parent_inodeno, g_parent_inode))
+		goto fail;
+	/* check if the filename is already present in root */
+	existing_file_inodeno = ext4fs_filename_check(filename);
+	if (existing_file_inodeno != -1) {
+		ret = ext4fs_delete_file(existing_file_inodeno);
+		fs->first_pass_bbmap = 0;
+		fs->curr_blkno = 0;
+
+		fs->first_pass_ibmap = 0;
+		fs->curr_inode_no = 0;
+		if (ret)
+			goto fail;
+	}
+	/* calucalate how many blocks required */
+	bytes_reqd_for_file = sizebytes;
+	blks_reqd_for_file = bytes_reqd_for_file / fs->blksz;
+	if (bytes_reqd_for_file % fs->blksz != 0) {
+		blks_reqd_for_file++;
+		debug("total bytes for a file %u\n", blks_reqd_for_file);
+	}
+	blocks_remaining = blks_reqd_for_file;
+	/* test for available space in partition */
+	if (fs->sb->free_blocks < blks_reqd_for_file) {
+		printf("Not enough space on partition !!!\n");
+		goto fail;
+	}
+
+	ext4fs_update_parent_dentry(filename, &inodeno, FILETYPE_REG);
+	/* prepare file inode */
+	inode_buffer = zalloc(fs->inodesz);
+	if (!inode_buffer)
+		goto fail;
+	file_inode = (struct ext2_inode *)inode_buffer;
+	file_inode->mode = S_IFREG | S_IRWXU |
+	    S_IRGRP | S_IROTH | S_IXGRP | S_IXOTH;
+	/* ToDo: Update correct time */
+	file_inode->mtime = timestamp;
+	file_inode->atime = timestamp;
+	file_inode->ctime = timestamp;
+	file_inode->nlinks = 1;
+	file_inode->size = sizebytes;
+
+	/* Allocate data blocks */
+	ext4fs_allocate_blocks(file_inode, blocks_remaining,
+			       &blks_reqd_for_file);
+	file_inode->blockcnt = (blks_reqd_for_file * fs->blksz) / SECTOR_SIZE;
+
+	temp_ptr = zalloc(fs->blksz);
+	if (!temp_ptr)
+		goto fail;
+	ibmap_idx = inodeno / ext4fs_root->sblock.inodes_per_group;
+	inodeno--;
+	itable_blkno = __le32_to_cpu(fs->gd[ibmap_idx].inode_table_id) +
+			(inodeno % __le32_to_cpu(sblock->inodes_per_group)) /
+			inodes_per_block;
+	blkoff = (inodeno % inodes_per_block) * fs->inodesz;
+	ext4fs_devread(itable_blkno * fs->sect_perblk, 0, fs->blksz, temp_ptr);
+	if (ext4fs_log_journal(temp_ptr, itable_blkno))
+		goto fail;
+
+	memcpy(temp_ptr + blkoff, inode_buffer, fs->inodesz);
+	if (ext4fs_put_metadata(temp_ptr, itable_blkno))
+		goto fail;
+	/* copy the file content into data blocks */
+	if (ext4fs_write_file(file_inode, 0, sizebytes, (char *)buffer) == -1) {
+		printf("Error in copying content\n");
+		goto fail;
+	}
+	ibmap_idx = parent_inodeno / ext4fs_root->sblock.inodes_per_group;
+	parent_inodeno--;
+	parent_itable_blkno = __le32_to_cpu(fs->gd[ibmap_idx].inode_table_id) +
+	    (parent_inodeno %
+	     __le32_to_cpu(sblock->inodes_per_group)) / inodes_per_block;
+	blkoff = (parent_inodeno % inodes_per_block) * fs->inodesz;
+	if (parent_itable_blkno != itable_blkno) {
+		memset(temp_ptr, '\0', fs->blksz);
+		ext4fs_devread(parent_itable_blkno * fs->sect_perblk,
+			       0, fs->blksz, temp_ptr);
+		if (ext4fs_log_journal(temp_ptr, parent_itable_blkno))
+			goto fail;
+
+		memcpy(temp_ptr + blkoff, g_parent_inode,
+			sizeof(struct ext2_inode));
+		if (ext4fs_put_metadata(temp_ptr, parent_itable_blkno))
+			goto fail;
+		free(temp_ptr);
+	} else {
+		/*
+		 * If parent and child fall in same inode table block
+		 * both should be kept in 1 buffer
+		 */
+		memcpy(temp_ptr + blkoff, g_parent_inode,
+		       sizeof(struct ext2_inode));
+		gd_index--;
+		if (ext4fs_put_metadata(temp_ptr, itable_blkno))
+			goto fail;
+		free(temp_ptr);
+	}
+	ext4fs_update();
+	ext4fs_deinit();
+
+	fs->first_pass_bbmap = 0;
+	fs->curr_blkno = 0;
+	fs->first_pass_ibmap = 0;
+	fs->curr_inode_no = 0;
+	free(inode_buffer);
+	free(g_parent_inode);
+	g_parent_inode = NULL;
+
+	return 0;
+fail:
+	ext4fs_deinit();
+	free(inode_buffer);
+	free(g_parent_inode);
+	g_parent_inode = NULL;
+
+	return -1;
+}
+#endif