[thirdparty/e2fsprogs.git] / lib / ext2fs / csum.c

/*
 * csum.c --- checksumming of ext3 structures
 *
 * Copyright (C) 2006 Cluster File Systems, Inc.
 * Copyright (C) 2006, 2007 by Andreas Dilger <adilger@clusterfs.com>
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Library
 * General Public License, version 2.
 * %End-Header%
 */

#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#include "ext2_fs.h"
#include "ext2fs.h"
#include "crc16.h"
#include <assert.h>

#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif

#ifdef DEBUG
#define STATIC
#else
#define STATIC static
#endif

STATIC __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
{
	__u16 crc = 0;
	struct ext2_group_desc *desc;
	size_t size;

	size = fs->super->s_desc_size;
	if (size < EXT2_MIN_DESC_SIZE)
		size = EXT2_MIN_DESC_SIZE;
	if (size > sizeof(struct ext4_group_desc)) {
		printf("%s: illegal s_desc_size(%zd)\n", __func__, size);
		size = sizeof(struct ext4_group_desc);
	}

	desc = ext2fs_group_desc(fs, fs->group_desc, group);

	if (fs->super->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
		int offset = offsetof(struct ext2_group_desc, bg_checksum);

#ifdef WORDS_BIGENDIAN
		struct ext4_group_desc swabdesc;

		/* Have to swab back to little-endian to do the checksum */
		memcpy(&swabdesc, desc, size);
		ext2fs_swap_group_desc2(fs,
					(struct ext2_group_desc *) &swabdesc);
		desc = (struct ext2_group_desc *) &swabdesc;

		group = ext2fs_swab32(group);
#endif
		crc = ext2fs_crc16(~0, fs->super->s_uuid,
				   sizeof(fs->super->s_uuid));
		crc = ext2fs_crc16(crc, &group, sizeof(group));
		crc = ext2fs_crc16(crc, desc, offset);
		offset += sizeof(desc->bg_checksum); /* skip checksum */
		/* for checksum of struct ext4_group_desc do the rest...*/
		if (offset < size) {
			crc = ext2fs_crc16(crc, (char *)desc + offset,
					   size - offset);
		}
	}

	return crc;
}

int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
{
	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
	    (ext2fs_bg_checksum(fs, group) !=
	     ext2fs_group_desc_csum(fs, group)))
		return 0;

	return 1;
}

void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
{
	if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
					EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
		return;

	/* ext2fs_bg_checksum_set() sets the actual checksum field but
	 * does not calculate the checksum itself. */
	ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
}

static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
				   __u32 inodes_per_grp, dgrp_t grp_no)
{
	ext2_ino_t i, start_ino, end_ino;

	start_ino = grp_no * inodes_per_grp + 1;
	end_ino = start_ino + inodes_per_grp - 1;

	for (i = end_ino; i >= start_ino; i--) {
		if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
			return i - start_ino + 1;
	}
	return inodes_per_grp;
}

/* update the bitmap flags, set the itable high watermark, and calculate
 * checksums for the group descriptors */
errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
{
	struct ext2_super_block *sb = fs->super;
	int dirty = 0;
	dgrp_t i;

	if (!fs->inode_map)
		return EXT2_ET_NO_INODE_BITMAP;

	if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
					EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
		return 0;

	for (i = 0; i < fs->group_desc_count; i++) {
		unsigned int old_csum = ext2fs_bg_checksum(fs, i);
		int old_unused = ext2fs_bg_itable_unused(fs, i);
		unsigned int old_flags = ext2fs_bg_flags(fs, i);
		int old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);

		if (old_free_inodes_count == sb->s_inodes_per_group) {
			ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
			ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
		} else {
			int unused =
				sb->s_inodes_per_group -
				find_last_inode_ingrp(fs->inode_map,
						      sb->s_inodes_per_group, i);

			ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
			ext2fs_bg_itable_unused_set(fs, i, unused);
		}

		ext2fs_group_desc_csum_set(fs, i);
		if (old_flags != ext2fs_bg_flags(fs, i))
			dirty = 1;
		if (old_unused != ext2fs_bg_itable_unused(fs, i))
			dirty = 1;
		if (old_csum != ext2fs_bg_checksum(fs, i))
			dirty = 1;
	}
	if (dirty)
		ext2fs_mark_super_dirty(fs);
	return 0;
}

#ifdef DEBUG
void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
{
	__u16 crc1, crc2, crc3;
	dgrp_t swabgroup;
 	struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc, group);
	size_t size;
	struct ext2_super_block *sb = fs->super;
	int offset = offsetof(struct ext2_group_desc, bg_checksum);
#ifdef WORDS_BIGENDIAN
	struct ext4_group_desc swabdesc;
#endif

	size = fs->super->s_desc_size;
	if (size < EXT2_MIN_DESC_SIZE)
		size = EXT2_MIN_DESC_SIZE;
	if (size > sizeof(struct ext4_group_desc))
		size = sizeof(struct ext4_group_desc);
#ifdef WORDS_BIGENDIAN
	/* Have to swab back to little-endian to do the checksum */
	memcpy(&swabdesc, desc, size);
	ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
	desc = (struct ext2_group_desc *) &swabdesc;

	swabgroup = ext2fs_swab32(group);
#else
	swabgroup = group;
#endif

	crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
	crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
	crc3 = ext2fs_crc16(crc2, desc, offset);
	offset += sizeof(desc->bg_checksum); /* skip checksum */
	/* for checksum of struct ext4_group_desc do the rest...*/
	if (offset < size)
		crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);

	printf("%s: UUID %016Lx%016Lx(%04x), grp %u(%04x): %04x=%04x\n",
	       msg, *(long long *)&sb->s_uuid, *(long long *)&sb->s_uuid[8],
	       crc1, group, crc2, crc3, ext2fs_group_desc_csum(fs, group));
}

unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
			      0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };

int main(int argc, char **argv)
{
	struct ext2_super_block param;
	errcode_t		retval;
	ext2_filsys		fs;
	int			i;
	__u16 csum1, csum2, csum_known = 0xd3a4;

	memset(&param, 0, sizeof(param));
	ext2fs_blocks_count_set(&param, 32768);

	retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
				   test_io_manager, &fs);
	if (retval) {
		com_err("setup", retval,
			"While initializing filesystem");
		exit(1);
	}
	memcpy(fs->super->s_uuid, sb_uuid, 16);
	fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;

	for (i=0; i < fs->group_desc_count; i++) {
		ext2fs_block_bitmap_loc_set(fs, i, 124);
		ext2fs_inode_bitmap_loc_set(fs, i, 125);
		ext2fs_inode_table_loc_set(fs, i, 126);
		ext2fs_bg_free_blocks_count_set(fs, i, 31119);
		ext2fs_bg_free_inodes_count_set(fs, i, 15701);
		ext2fs_bg_used_dirs_count_set(fs, i, 2);
		ext2fs_bg_flags_zap(fs, i);
	};

	csum1 = ext2fs_group_desc_csum(fs, 0);
	print_csum("csum0000", fs, 0);

	if (csum1 != csum_known) {
		printf("checksum for group 0 should be %04x\n", csum_known);
		exit(1);
	}
	csum2 = ext2fs_group_desc_csum(fs, 1);
	print_csum("csum0001", fs, 1);
	if (csum1 == csum2) {
		printf("checksums for different groups shouldn't match\n");
		exit(1);
	}
	csum2 = ext2fs_group_desc_csum(fs, 2);
	print_csum("csumffff", fs, 2);
	if (csum1 == csum2) {
		printf("checksums for different groups shouldn't match\n");
		exit(1);
	}
	ext2fs_bg_checksum_set(fs, 0, csum1);
	csum2 = ext2fs_group_desc_csum(fs, 0);
	print_csum("csum_set", fs, 0);
	if (csum1 != csum2) {
		printf("checksums should not depend on checksum field\n");
		exit(1);
	}
	if (!ext2fs_group_desc_csum_verify(fs, 0)) {
		printf("checksums should verify against gd_checksum\n");
		exit(1);
	}
	memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
	print_csum("new_uuid", fs, 0);
	if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
		printf("checksums for different filesystems shouldn't match\n");
		exit(1);
	}
	csum1 = ext2fs_group_desc_csum(fs, 0);
	ext2fs_bg_checksum_set(fs, 0, csum1);
	print_csum("csum_new", fs, 0);
	ext2fs_bg_free_blocks_count_set(fs, 0, 1);
	csum2 = ext2fs_group_desc_csum(fs, 0);
	print_csum("csum_blk", fs, 0);
	if (csum1 == csum2) {
		printf("checksums for different data shouldn't match\n");
		exit(1);
	}

	return 0;
}
#endif
Commit	Line	Data
ca2634a4 JS	1	/*
	2	* csum.c --- checksumming of ext3 structures
	3	*
	4	* Copyright (C) 2006 Cluster File Systems, Inc.
470e737a	5	* Copyright (C) 2006, 2007 by Andreas Dilger <adilger@clusterfs.com>
ca2634a4 JS	6	*
ca2634a4 JS	7	* %Begin-Header%
543547a5 TT	8	* This file may be redistributed under the terms of the GNU Library
543547a5 TT	9	* General Public License, version 2.
ca2634a4 JS	10	* %End-Header%
	11	*/
	12
0eeec8ac TT	13	#if HAVE_SYS_TYPES_H
	14	#include <sys/types.h>
	15	#endif
	16
ca2634a4 JS	17	#include "ext2_fs.h"
	18	#include "ext2fs.h"
	19	#include "crc16.h"
	20	#include <assert.h>
	21
	22	#ifndef offsetof
	23	#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
	24	#endif
	25
	26	#ifdef DEBUG
	27	#define STATIC
	28	#else
	29	#define STATIC static
	30	#endif
	31
	32	STATIC __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
	33	{
	34	__u16 crc = 0;
	35	struct ext2_group_desc *desc;
1d18a55c TT	36	size_t size;
	37
	38	size = fs->super->s_desc_size;
	39	if (size < EXT2_MIN_DESC_SIZE)
	40	size = EXT2_MIN_DESC_SIZE;
	41	if (size > sizeof(struct ext4_group_desc)) {
	42	printf("%s: illegal s_desc_size(%zd)\n", __func__, size);
	43	size = sizeof(struct ext4_group_desc);
	44	}
ca2634a4	45
d7cca6b0	46	desc = ext2fs_group_desc(fs, fs->group_desc, group);
ca2634a4 JS	47
	48	if (fs->super->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
	49	int offset = offsetof(struct ext2_group_desc, bg_checksum);
	50
	51	#ifdef WORDS_BIGENDIAN
1d18a55c	52	struct ext4_group_desc swabdesc;
ca2634a4 JS	53
ca2634a4 JS	54	/* Have to swab back to little-endian to do the checksum */
1d18a55c TT	55	memcpy(&swabdesc, desc, size);
	56	ext2fs_swap_group_desc2(fs,
	57	(struct ext2_group_desc *) &swabdesc);
	58	desc = (struct ext2_group_desc *) &swabdesc;
ca2634a4 JS	59
	60	group = ext2fs_swab32(group);
	61	#endif
c4dcb1c1 TT	62	crc = ext2fs_crc16(~0, fs->super->s_uuid,
	63	sizeof(fs->super->s_uuid));
	64	crc = ext2fs_crc16(crc, &group, sizeof(group));
	65	crc = ext2fs_crc16(crc, desc, offset);
ca2634a4	66	offset += sizeof(desc->bg_checksum); /* skip checksum */
ca2634a4	67	/* for checksum of struct ext4_group_desc do the rest...*/
1d18a55c	68	if (offset < size) {
c4dcb1c1	69	crc = ext2fs_crc16(crc, (char *)desc + offset,
1d18a55c	70	size - offset);
ca2634a4 JS	71	}
	72	}
	73
	74	return crc;
	75	}
	76
	77	int ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group)
	78	{
4729455f TT	79	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
4729455f TT	80	EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
d7cca6b0	81	(ext2fs_bg_checksum(fs, group) !=
4729455f	82	ext2fs_group_desc_csum(fs, group)))
ca2634a4 JS	83	return 0;
	84
	85	return 1;
	86	}
	87
	88	void ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group)
	89	{
d7cca6b0 VAH	90	if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
	91	EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
	92	return;
	93
	94	/* ext2fs_bg_checksum_set() sets the actual checksum field but
	95	* does not calculate the checksum itself. */
	96	ext2fs_bg_checksum_set(fs, group, ext2fs_group_desc_csum(fs, group));
ca2634a4 JS	97	}
	98
	99	static __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap,
	100	__u32 inodes_per_grp, dgrp_t grp_no)
	101	{
	102	ext2_ino_t i, start_ino, end_ino;
	103
	104	start_ino = grp_no * inodes_per_grp + 1;
	105	end_ino = start_ino + inodes_per_grp - 1;
	106
	107	for (i = end_ino; i >= start_ino; i--) {
8f82ef98	108	if (ext2fs_fast_test_inode_bitmap2(bitmap, i))
ca2634a4 JS	109	return i - start_ino + 1;
	110	}
	111	return inodes_per_grp;
	112	}
	113
	114	/* update the bitmap flags, set the itable high watermark, and calculate
	115	* checksums for the group descriptors */
f628acea	116	errcode_t ext2fs_set_gdt_csum(ext2_filsys fs)
ca2634a4 JS	117	{
ca2634a4 JS	118	struct ext2_super_block *sb = fs->super;
8895f43a	119	int dirty = 0;
ca2634a4 JS	120	dgrp_t i;
ca2634a4 JS	121
f628acea AD	122	if (!fs->inode_map)
	123	return EXT2_ET_NO_INODE_BITMAP;
	124
16b851cd TT	125	if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
16b851cd TT	126	EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
f628acea	127	return 0;
ca2634a4	128
d7cca6b0 VAH	129	for (i = 0; i < fs->group_desc_count; i++) {
	130	unsigned int old_csum = ext2fs_bg_checksum(fs, i);
	131	int old_unused = ext2fs_bg_itable_unused(fs, i);
	132	unsigned int old_flags = ext2fs_bg_flags(fs, i);
	133	int old_free_inodes_count = ext2fs_bg_free_inodes_count(fs, i);
ca2634a4	134
d7cca6b0 VAH	135	if (old_free_inodes_count == sb->s_inodes_per_group) {
	136	ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
	137	ext2fs_bg_itable_unused_set(fs, i, sb->s_inodes_per_group);
16b851cd	138	} else {
d7cca6b0 VAH	139	int unused =
d7cca6b0 VAH	140	sb->s_inodes_per_group -
ca2634a4	141	find_last_inode_ingrp(fs->inode_map,
d7cca6b0 VAH	142	sb->s_inodes_per_group, i);
	143
	144	ext2fs_bg_flags_clear(fs, i, EXT2_BG_INODE_UNINIT);
	145	ext2fs_bg_itable_unused_set(fs, i, unused);
ca2634a4 JS	146	}
ca2634a4 JS	147
ca2634a4	148	ext2fs_group_desc_csum_set(fs, i);
d7cca6b0	149	if (old_flags != ext2fs_bg_flags(fs, i))
80fc4e69	150	dirty = 1;
d7cca6b0	151	if (old_unused != ext2fs_bg_itable_unused(fs, i))
80fc4e69	152	dirty = 1;
d7cca6b0	153	if (old_csum != ext2fs_bg_checksum(fs, i))
ca2634a4 JS	154	dirty = 1;
	155	}
	156	if (dirty)
	157	ext2fs_mark_super_dirty(fs);
f628acea	158	return 0;
ca2634a4	159	}
470e737a TT	160
	161	#ifdef DEBUG
	162	void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
	163	{
	164	__u16 crc1, crc2, crc3;
	165	dgrp_t swabgroup;
cf828f1a	166	struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc, group);
1d18a55c	167	size_t size;
470e737a	168	struct ext2_super_block *sb = fs->super;
1d18a55c	169	int offset = offsetof(struct ext2_group_desc, bg_checksum);
470e737a	170	#ifdef WORDS_BIGENDIAN
1d18a55c TT	171	struct ext4_group_desc swabdesc;
1d18a55c TT	172	#endif
470e737a	173
1d18a55c TT	174	size = fs->super->s_desc_size;
	175	if (size < EXT2_MIN_DESC_SIZE)
	176	size = EXT2_MIN_DESC_SIZE;
	177	if (size > sizeof(struct ext4_group_desc))
	178	size = sizeof(struct ext4_group_desc);
	179	#ifdef WORDS_BIGENDIAN
470e737a	180	/* Have to swab back to little-endian to do the checksum */
1d18a55c TT	181	memcpy(&swabdesc, desc, size);
	182	ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
	183	desc = (struct ext2_group_desc *) &swabdesc;
470e737a TT	184
	185	swabgroup = ext2fs_swab32(group);
	186	#else
	187	swabgroup = group;
	188	#endif
	189
	190	crc1 = ext2fs_crc16(~0, sb->s_uuid, sizeof(fs->super->s_uuid));
	191	crc2 = ext2fs_crc16(crc1, &swabgroup, sizeof(swabgroup));
1d18a55c TT	192	crc3 = ext2fs_crc16(crc2, desc, offset);
	193	offset += sizeof(desc->bg_checksum); /* skip checksum */
	194	/* for checksum of struct ext4_group_desc do the rest...*/
	195	if (offset < size)
	196	crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
	197
470e737a TT	198	printf("%s: UUID %016Lx%016Lx(%04x), grp %u(%04x): %04x=%04x\n",
	199	msg, (long long )&sb->s_uuid, (long long )&sb->s_uuid[8],
	200	crc1, group, crc2, crc3, ext2fs_group_desc_csum(fs, group));
	201	}
	202
	203	unsigned char sb_uuid[16] = { 0x4f, 0x25, 0xe8, 0xcf, 0xe7, 0x97, 0x48, 0x23,
	204	0xbe, 0xfa, 0xa7, 0x88, 0x4b, 0xae, 0xec, 0xdb };
	205
	206	int main(int argc, char **argv)
	207	{
	208	struct ext2_super_block param;
	209	errcode_t retval;
	210	ext2_filsys fs;
	211	int i;
	212	__u16 csum1, csum2, csum_known = 0xd3a4;
	213
	214	memset(&param, 0, sizeof(param));
4efbac6f	215	ext2fs_blocks_count_set(&param, 32768);
470e737a	216
8f82ef98	217	retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
470e737a TT	218	test_io_manager, &fs);
	219	if (retval) {
	220	com_err("setup", retval,
	221	"While initializing filesystem");
	222	exit(1);
	223	}
	224	memcpy(fs->super->s_uuid, sb_uuid, 16);
	225	fs->super->s_feature_ro_compat = EXT4_FEATURE_RO_COMPAT_GDT_CSUM;
	226
	227	for (i=0; i < fs->group_desc_count; i++) {
d7cca6b0 VAH	228	ext2fs_block_bitmap_loc_set(fs, i, 124);
	229	ext2fs_inode_bitmap_loc_set(fs, i, 125);
	230	ext2fs_inode_table_loc_set(fs, i, 126);
	231	ext2fs_bg_free_blocks_count_set(fs, i, 31119);
	232	ext2fs_bg_free_inodes_count_set(fs, i, 15701);
	233	ext2fs_bg_used_dirs_count_set(fs, i, 2);
e633b58a	234	ext2fs_bg_flags_zap(fs, i);
470e737a TT	235	};
	236
	237	csum1 = ext2fs_group_desc_csum(fs, 0);
	238	print_csum("csum0000", fs, 0);
	239
	240	if (csum1 != csum_known) {
	241	printf("checksum for group 0 should be %04x\n", csum_known);
	242	exit(1);
	243	}
	244	csum2 = ext2fs_group_desc_csum(fs, 1);
	245	print_csum("csum0001", fs, 1);
	246	if (csum1 == csum2) {
	247	printf("checksums for different groups shouldn't match\n");
	248	exit(1);
	249	}
	250	csum2 = ext2fs_group_desc_csum(fs, 2);
	251	print_csum("csumffff", fs, 2);
	252	if (csum1 == csum2) {
	253	printf("checksums for different groups shouldn't match\n");
	254	exit(1);
	255	}
d7cca6b0	256	ext2fs_bg_checksum_set(fs, 0, csum1);
470e737a TT	257	csum2 = ext2fs_group_desc_csum(fs, 0);
	258	print_csum("csum_set", fs, 0);
	259	if (csum1 != csum2) {
	260	printf("checksums should not depend on checksum field\n");
	261	exit(1);
	262	}
	263	if (!ext2fs_group_desc_csum_verify(fs, 0)) {
	264	printf("checksums should verify against gd_checksum\n");
	265	exit(1);
	266	}
	267	memset(fs->super->s_uuid, 0x30, sizeof(fs->super->s_uuid));
	268	print_csum("new_uuid", fs, 0);
	269	if (ext2fs_group_desc_csum_verify(fs, 0) != 0) {
	270	printf("checksums for different filesystems shouldn't match\n");
	271	exit(1);
	272	}
d7cca6b0 VAH	273	csum1 = ext2fs_group_desc_csum(fs, 0);
d7cca6b0 VAH	274	ext2fs_bg_checksum_set(fs, 0, csum1);
470e737a	275	print_csum("csum_new", fs, 0);
d7cca6b0	276	ext2fs_bg_free_blocks_count_set(fs, 0, 1);
470e737a TT	277	csum2 = ext2fs_group_desc_csum(fs, 0);
	278	print_csum("csum_blk", fs, 0);
	279	if (csum1 == csum2) {
	280	printf("checksums for different data shouldn't match\n");
	281	exit(1);
	282	}
	283
	284	return 0;
	285	}
	286	#endif