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1// SPDX-License-Identifier: GPL-2.02/*3 * linux/fs/ext4/bitmap.c4 *5 * Copyright (C) 1992, 1993, 1994, 19956 * Remy Card (card@masi.ibp.fr)7 * Laboratoire MASI - Institut Blaise Pascal8 * Universite Pierre et Marie Curie (Paris VI)9 */10 11#include <linux/buffer_head.h>12#include "ext4.h"13 14unsigned int ext4_count_free(char *bitmap, unsigned int numchars)15{16 return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);17}18 19int ext4_inode_bitmap_csum_verify(struct super_block *sb,20 struct ext4_group_desc *gdp,21 struct buffer_head *bh)22{23 __u32 hi;24 __u32 provided, calculated;25 struct ext4_sb_info *sbi = EXT4_SB(sb);26 int sz;27 28 if (!ext4_has_metadata_csum(sb))29 return 1;30 31 sz = EXT4_INODES_PER_GROUP(sb) >> 3;32 provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);33 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);34 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {35 hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);36 provided |= (hi << 16);37 } else38 calculated &= 0xFFFF;39 40 return provided == calculated;41}42 43void ext4_inode_bitmap_csum_set(struct super_block *sb,44 struct ext4_group_desc *gdp,45 struct buffer_head *bh)46{47 __u32 csum;48 struct ext4_sb_info *sbi = EXT4_SB(sb);49 int sz;50 51 if (!ext4_has_metadata_csum(sb))52 return;53 54 sz = EXT4_INODES_PER_GROUP(sb) >> 3;55 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);56 gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);57 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)58 gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);59}60 61int ext4_block_bitmap_csum_verify(struct super_block *sb,62 struct ext4_group_desc *gdp,63 struct buffer_head *bh)64{65 __u32 hi;66 __u32 provided, calculated;67 struct ext4_sb_info *sbi = EXT4_SB(sb);68 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;69 70 if (!ext4_has_metadata_csum(sb))71 return 1;72 73 provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);74 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);75 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {76 hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);77 provided |= (hi << 16);78 } else79 calculated &= 0xFFFF;80 81 return provided == calculated;82}83 84void ext4_block_bitmap_csum_set(struct super_block *sb,85 struct ext4_group_desc *gdp,86 struct buffer_head *bh)87{88 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;89 __u32 csum;90 struct ext4_sb_info *sbi = EXT4_SB(sb);91 92 if (!ext4_has_metadata_csum(sb))93 return;94 95 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);96 gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);97 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)98 gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);99}100