ext4_common.c

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

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

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

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

#if defined(CONFIG_EXT4_WRITE)
static inline void ext4fs_sb_free_inodes_dec(struct ext2_sblock *sb)
{
	sb->free_inodes = cpu_to_le32(le32_to_cpu(sb->free_inodes) - 1);
}

static inline void ext4fs_sb_free_blocks_dec(struct ext2_sblock *sb)
{
	sb->free_blocks = cpu_to_le32(le32_to_cpu(sb->free_blocks) - 1);
}

static inline void ext4fs_bg_free_inodes_dec(struct ext2_block_group *bg)
{
	bg->free_inodes = cpu_to_le16(le16_to_cpu(bg->free_inodes) - 1);
}

static inline void ext4fs_bg_free_blocks_dec(struct ext2_block_group *bg)
{
	bg->free_blocks = cpu_to_le16(le16_to_cpu(bg->free_blocks) - 1);
}

static inline void ext4fs_bg_itable_unused_dec(struct ext2_block_group *bg)
{
	bg->bg_itable_unused = cpu_to_le16(le16_to_cpu(bg->bg_itable_unused) - 1);
}

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

	return res;
}

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

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

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

	if ((startblock + (size >> log2blksz)) >
	    (part_offset + fs->total_sect)) {
		printf("part_offset is " LBAFU "\n", part_offset);
		printf("total_sector is %" PRIu64 "\n", fs->total_sect);
		printf("error: overflow occurs\n");
		return;
	}

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

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

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

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

	return -1;
}

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

	*ptr = *ptr | operand;

	return 0;
}

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

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

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

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

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

	return crc;
}

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

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

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

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

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

	return 0;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	return inodeno;
}

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

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

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

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

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

		offset = 0;
		do {
			dir = (struct ext2_dirent *)(block_buffer + offset);
			direntname = (char*)(dir) + sizeof(struct ext2_dirent);

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

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

			offset += direntlen;

		} while (offset < fs->blksz);

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

fail:
	free(block_buffer);

	return -1;
}

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

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

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

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

	return 0;
}

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

	return 0;
}

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

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

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

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

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

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

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

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

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

	return result_inode_no;
}

static int unlink_filename(char *filename, unsigned int blknr)
{
	int totalbytes = 0;
	int templength = 0;
	int status, inodeno;
	int found = 0;
	char *root_first_block_buffer = NULL;
	struct ext2_dirent *dir = NULL;
	struct ext2_dirent *previous_dir = NULL;
	char *ptr = NULL;
	struct ext_filesystem *fs = get_fs();
	int ret = -1;

	/* get the first block of root */
	root_first_block_buffer = zalloc(fs->blksz);
	if (!root_first_block_buffer)
		return -ENOMEM;
	status = ext4fs_devread((lbaint_t)blknr * fs->sect_perblk, 0,
				fs->blksz, root_first_block_buffer);
	if (status == 0)
		goto fail;

	if (ext4fs_log_journal(root_first_block_buffer, blknr))
		goto fail;
	dir = (struct ext2_dirent *)root_first_block_buffer;
	ptr = (char *)dir;
	totalbytes = 0;
	while (le16_to_cpu(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 (dir->inode && (strlen(filename) == dir->namelen) &&
		    (strncmp(ptr + sizeof(struct ext2_dirent),
			     filename, dir->namelen) == 0)) {
			printf("file found, deleting\n");
			inodeno = le32_to_cpu(dir->inode);
			if (previous_dir) {
				uint16_t new_len;
				new_len = le16_to_cpu(previous_dir->direntlen);
				new_len += le16_to_cpu(dir->direntlen);
				previous_dir->direntlen = cpu_to_le16(new_len);
			} else {
				dir->inode = 0;
			}
			found = 1;
			break;
		}

		if (fs->blksz - totalbytes == le16_to_cpu(dir->direntlen))
			break;

		/* traversing the each directory entry */
		templength = le16_to_cpu(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_buffer, blknr))
			goto fail;
		ret = inodeno;
	}
fail:
	free(root_first_block_buffer);

	return ret;
}

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

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

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

	return -1;
}

uint32_t ext4fs_get_new_blk_no(void)
{
	short i;
	short status;
	int remainder;
	unsigned int bg_idx;
	static int prev_bg_bitmap_index = -1;
	unsigned int blk_per_grp = le32_to_cpu(ext4fs_root->sblock.blocks_per_group);
	struct ext_filesystem *fs = get_fs();
	char *journal_buffer = zalloc(fs->blksz);
	char *zero_buffer = zalloc(fs->blksz);
	if (!journal_buffer || !zero_buffer)
		goto fail;
	struct ext2_block_group *bgd = (struct ext2_block_group *)fs->gdtable;

	if (fs->first_pass_bbmap == 0) {
		for (i = 0; i < fs->no_blkgrp; i++) {
			if (le16_to_cpu(bgd[i].free_blocks)) {
				if (le16_to_cpu(bgd[i].bg_flags) & EXT4_BG_BLOCK_UNINIT) {
					uint16_t new_flags;
					put_ext4((uint64_t)le32_to_cpu(bgd[i].block_id) * fs->blksz,
						 zero_buffer, fs->blksz);
					new_flags = le16_to_cpu(bgd[i].bg_flags) & ~EXT4_BG_BLOCK_UNINIT;
					bgd[i].bg_flags = cpu_to_le16(new_flags);
					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++;
				ext4fs_bg_free_blocks_dec(&bgd[i]);
				ext4fs_sb_free_blocks_dec(fs->sb);
				status = ext4fs_devread(
							(lbaint_t)le32_to_cpu(bgd[i].block_id) *
							fs->sect_perblk, 0,
							fs->blksz,
							journal_buffer);
				if (status == 0)
					goto fail;
				if (ext4fs_log_journal(journal_buffer,
							le32_to_cpu(bgd[i].block_id)))
					goto fail;
				goto success;
			} else {
				debug("no space left on block group %d\n", i);
			}
		}

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

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

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

		if (le16_to_cpu(bgd[bg_idx].bg_flags) & EXT4_BG_BLOCK_UNINIT) {
			uint16_t new_flags;
			put_ext4((uint64_t)le32_to_cpu(bgd[bg_idx].block_id) * fs->blksz,
				 zero_buffer, fs->blksz);
			memcpy(fs->blk_bmaps[bg_idx], zero_buffer, fs->blksz);
			new_flags = le16_to_cpu(bgd[bg_idx].bg_flags) & ~EXT4_BG_BLOCK_UNINIT;
			bgd[bg_idx].bg_flags = cpu_to_le16(new_flags);
		}

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

		/* journal backup */
		if (prev_bg_bitmap_index != bg_idx) {
			status = ext4fs_devread(
						(lbaint_t)le32_to_cpu(bgd[bg_idx].block_id)
						* fs->sect_perblk,
						0, fs->blksz, journal_buffer);
			if (status == 0)
				goto fail;
			if (ext4fs_log_journal(journal_buffer,
						le32_to_cpu(bgd[bg_idx].block_id)))
				goto fail;

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

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

	return -1;
}

int ext4fs_get_new_inode_no(void)
{
	short i;
	short status;
	unsigned int ibmap_idx;
	static int prev_inode_bitmap_index = -1;
	unsigned int inodes_per_grp = le32_to_cpu(ext4fs_root->sblock.inodes_per_group);
	struct ext_filesystem *fs = get_fs();
	char *journal_buffer = zalloc(fs->blksz);
	char *zero_buffer = zalloc(fs->blksz);
	if (!journal_buffer || !zero_buffer)
		goto fail;
	struct ext2_block_group *bgd = (struct ext2_block_group *)fs->gdtable;
	int has_gdt_chksum = le32_to_cpu(fs->sb->feature_ro_compat) &
		EXT4_FEATURE_RO_COMPAT_GDT_CSUM ? 1 : 0;

	if (fs->first_pass_ibmap == 0) {
		for (i = 0; i < fs->no_blkgrp; i++) {
			if (bgd[i].free_inodes) {
				if (has_gdt_chksum)
					bgd[i].bg_itable_unused =
						bgd[i].free_inodes;
				if (le16_to_cpu(bgd[i].bg_flags) & EXT4_BG_INODE_UNINIT) {