/* vi: set sw=4 ts=4: *//* * sparse.c --- find the groups in an ext2 filesystem with metadata backups * * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. * Copyright (C) 2002 Andreas Dilger. * * %Begin-Header% * This file may be redistributed under the terms of the GNU Public * License. * %End-Header% */#include <stdio.h>#include "ext2_fs.h"#include "ext2fsP.h"static int test_root(int a, int b){	if (a == 0)		return 1;	while (1) {		if (a == 1)			return 1;		if (a % b)			return 0;		a = a / b;	}}int ext2fs_bg_has_super(ext2_filsys fs, int group_block){	if (!(fs->super->s_feature_ro_compat &	      EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))		return 1;	if (test_root(group_block, 3) || (test_root(group_block, 5)) ||	    test_root(group_block, 7))		return 1;	return 0;}/* * Iterate through the groups which hold BACKUP superblock/GDT copies in an * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before * calling this for the first time.  In a sparse filesystem it will be the * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... */unsigned int ext2fs_list_backups(ext2_filsys fs, unsigned int *three,				 unsigned int *five, unsigned int *seven){	unsigned int *min = three;	int mult = 3;	unsigned int ret;	if (!(fs->super->s_feature_ro_compat &	      EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) {		ret = *min;		*min += 1;		return ret;	}	if (*five < *min) {		min = five;		mult = 5;	}	if (*seven < *min) {		min = seven;		mult = 7;	}	ret = *min;	*min *= mult;	return ret;}