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>

common/cmd_ext4.c

@@ -62,6 +62,10 @@
 
 uint64_t total_sector;
 uint64_t part_offset;
+#if defined(CONFIG_CMD_EXT4_WRITE)
+static uint64_t part_size;
+static uint16_t cur_part = 1;
+#endif
 
 #define DOS_PART_MAGIC_OFFSET		0x1fe
 #define DOS_FS_TYPE_OFFSET		0x36
@@ -84,6 +88,143 @@ int do_ext4_ls(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 	return 0;
 }
 
+#if defined(CONFIG_CMD_EXT4_WRITE)
+static int ext4_register_device(block_dev_desc_t *dev_desc, int part_no)
+{
+	unsigned char buffer[SECTOR_SIZE];
+	disk_partition_t info;
+
+	if (!dev_desc->block_read)
+		return -1;
+
+	/* check if we have a MBR (on floppies we have only a PBR) */
+	if (dev_desc->block_read(dev_desc->dev, 0, 1, (ulong *) buffer) != 1) {
+		printf("** Can't read from device %d **\n", dev_desc->dev);
+		return -1;
+	}
+	if (buffer[DOS_PART_MAGIC_OFFSET] != 0x55 ||
+	    buffer[DOS_PART_MAGIC_OFFSET + 1] != 0xaa) {
+		/* no signature found */
+		return -1;
+	}
+
+	/* First we assume there is a MBR */
+	if (!get_partition_info(dev_desc, part_no, &info)) {
+		part_offset = info.start;
+		cur_part = part_no;
+		part_size = info.size;
+	} else if ((strncmp((char *)&buffer[DOS_FS_TYPE_OFFSET],
+			    "FAT", 3) == 0) || (strncmp((char *)&buffer
+							[DOS_FS32_TYPE_OFFSET],
+							"FAT32", 5) == 0)) {
+		/* ok, we assume we are on a PBR only */
+		cur_part = 1;
+		part_offset = 0;
+	} else {
+		printf("** Partition %d not valid on device %d **\n",
+		       part_no, dev_desc->dev);
+		return -1;
+	}
+
+	return 0;
+}
+
+int do_ext4_write(cmd_tbl_t *cmdtp, int flag, int argc,
+				char *const argv[])
+{
+	const char *filename = "/";
+	int part_length;
+	unsigned long part = 1;
+	int dev;
+	char *ep;
+	unsigned long ram_address;
+	unsigned long file_size;
+	disk_partition_t info;
+	struct ext_filesystem *fs;
+
+	if (argc < 6)
+		return cmd_usage(cmdtp);
+
+	dev = (int)simple_strtoul(argv[2], &ep, 16);
+	ext4_dev_desc = get_dev(argv[1], dev);
+	if (ext4_dev_desc == NULL) {
+		printf("Block device %s %d not supported\n", argv[1], dev);
+		return 1;
+	}
+	if (init_fs(ext4_dev_desc))
+		return 1;
+
+	fs = get_fs();
+	if (*ep) {
+		if (*ep != ':') {
+			puts("Invalid boot device, use `dev[:part]'\n");
+			goto fail;
+		}
+		part = simple_strtoul(++ep, NULL, 16);
+	}
+
+	/* get the filename */
+	filename = argv[3];
+
+	/* get the address in hexadecimal format (string to int) */
+	ram_address = simple_strtoul(argv[4], NULL, 16);
+
+	/* get the filesize in base 10 format */
+	file_size = simple_strtoul(argv[5], NULL, 10);
+
+	/* set the device as block device */
+	part_length = ext4fs_set_blk_dev(fs->dev_desc, part);
+	if (part_length == 0) {
+		printf("Bad partition - %s %d:%lu\n", argv[1], dev, part);
+		goto fail;
+	}
+
+	/* register the device and partition */
+	if (ext4_register_device(fs->dev_desc, part) != 0) {
+		printf("Unable to use %s %d:%lu for fattable\n",
+		       argv[1], dev, part);
+		goto fail;
+	}
+
+	/* get the partition information */
+	if (!get_partition_info(fs->dev_desc, part, &info)) {
+		total_sector = (info.size * info.blksz) / SECTOR_SIZE;
+		fs->total_sect = total_sector;
+	} else {
+		printf("error : get partition info\n");
+		goto fail;
+	}
+
+	/* mount the filesystem */
+	if (!ext4fs_mount(part_length)) {
+		printf("Bad ext4 partition %s %d:%lu\n", argv[1], dev, part);
+		goto fail;
+	}
+
+	/* start write */
+	if (ext4fs_write(filename, (unsigned char *)ram_address, file_size)) {
+		printf("** Error ext4fs_write() **\n");
+		goto fail;
+	}
+	ext4fs_close();
+	deinit_fs(fs->dev_desc);
+
+	return 0;
+
+fail:
+	ext4fs_close();
+	deinit_fs(fs->dev_desc);
+
+	return 1;
+}
+
+U_BOOT_CMD(ext4write, 6, 1, do_ext4_write,
+	"create a file in the root directory",
+	"<interface> <dev[:part]> [Absolute filename path] [Address] [sizebytes]\n"
+	"	  - create a file in / directory");
+
+#endif
+
 U_BOOT_CMD(ext4ls, 4, 1, do_ext4_ls,
 	   "list files in a directory (default /)",
 	   "<interface> <dev[:part]> [directory]\n"

doc/README.ext4

+This patch series adds support for ext4 ls,load and write features in uboot
+Journaling is supported for write feature.
+
+To Enable ext2 ls and load commands, modify the board specific config file with
+#define CONFIG_CMD_EXT2
+
+To Enable ext4 ls and load commands, modify the board specific config file with
+#define CONFIG_CMD_EXT4
+
+To enable ext4 write command, modify the board specific config file with
+#define CONFIG_CMD_EXT4
+#define CONFIG_CMD_EXT4_WRITE
+
+Steps to test:
+
+1. After applying the patch, ext4 specific commands can be seen
+   in the boot loader prompt using
+        UBOOT #help
+
+        ext4load- load binary file from a Ext4 file system
+        ext4ls  - list files in a directory (default /)
+        ext4write- create a file in ext4 formatted partition
+
+2. To list the files in ext4 formatted partition, execute
+        ext4ls <interface> <dev[:part]> [directory]
+        For example:
+        UBOOT #ext4ls mmc 0:5 /usr/lib
+
+3. To read and load a file from an ext4 formatted partition to RAM, execute
+        ext4load <interface> <dev[:part]> [addr] [filename] [bytes]
+        For example:
+        UBOOT #ext4load mmc 2:2 0x30007fc0 uImage
+
+4. To write a file to a ext4 formatted partition.
+        a) First load a file to RAM at a particular address for example 0x30007fc0.
+        Now execute ext4write command
+        ext4write <interface> <dev[:part]> [filename] [Address] [sizebytes]
+        For example:
+        UBOOT #ext4write mmc 2:2 /boot/uImage 0x30007fc0 6183120
+        (here 6183120 is the size of the file to be written)
+        Note: Absolute path is required for the file to be written
+
+References :
+	-- ext4 implementation in Linux Kernel
+	-- Uboot existing ext2 load and ls implementation
+	-- Journaling block device JBD2 implementation in linux Kernel

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))

fs/ext4/crc16.c

+/*
+ *      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;
+}

fs/ext4/crc16.h

+/*
+ * 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

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

fs/ext4/ext4_journal.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>
+ *
+ * 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;
+	}
+}
+