bitmap.c
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/*
* linux/fs/ext4/bitmap.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*/
#include <linux/buffer_head.h>
#include <linux/jbd2.h>
#include "ext4.h"
unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
{
return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
}
int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *gdp,
struct buffer_head *bh, int sz)
{
__u32 hi;
__u32 provided, calculated;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (!ext4_has_metadata_csum(sb))
return 1;
provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
provided |= (hi << 16);
} else
calculated &= 0xFFFF;
return provided == calculated;
}
void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *gdp,
struct buffer_head *bh, int sz)
{
__u32 csum;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (!ext4_has_metadata_csum(sb))
return;
csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
}
int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *gdp,
struct buffer_head *bh)
{
__u32 hi;
__u32 provided, calculated;
struct ext4_sb_info *sbi = EXT4_SB(sb);
int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
if (!ext4_has_metadata_csum(sb))
return 1;
provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
provided |= (hi << 16);
} else
calculated &= 0xFFFF;
if (provided == calculated)
return 1;
return 0;
}
void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *gdp,
struct buffer_head *bh)
{
int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
__u32 csum;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (!ext4_has_metadata_csum(sb))
return;
csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
}