1/*
2 *  linux/fs/ext4/bitmap.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 */
9
10#include <linux/buffer_head.h>
11#include "ext4.h"
12
13unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
14{
15	return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
16}
17
18int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
19				  struct ext4_group_desc *gdp,
20				  struct buffer_head *bh, int sz)
21{
22	__u32 hi;
23	__u32 provided, calculated;
24	struct ext4_sb_info *sbi = EXT4_SB(sb);
25
26	if (!ext4_has_metadata_csum(sb))
27		return 1;
28
29	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
30	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
31	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
32		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
33		provided |= (hi << 16);
34	} else
35		calculated &= 0xFFFF;
36
37	return provided == calculated;
38}
39
40void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
41				struct ext4_group_desc *gdp,
42				struct buffer_head *bh, int sz)
43{
44	__u32 csum;
45	struct ext4_sb_info *sbi = EXT4_SB(sb);
46
47	if (!ext4_has_metadata_csum(sb))
48		return;
49
50	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
51	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
52	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
53		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
54}
55
56int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
57				  struct ext4_group_desc *gdp,
58				  struct buffer_head *bh)
59{
60	__u32 hi;
61	__u32 provided, calculated;
62	struct ext4_sb_info *sbi = EXT4_SB(sb);
63	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
64
65	if (!ext4_has_metadata_csum(sb))
66		return 1;
67
68	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
69	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
70	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
71		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
72		provided |= (hi << 16);
73	} else
74		calculated &= 0xFFFF;
75
76	if (provided == calculated)
77		return 1;
78
79	return 0;
80}
81
82void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
83				struct ext4_group_desc *gdp,
84				struct buffer_head *bh)
85{
86	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
87	__u32 csum;
88	struct ext4_sb_info *sbi = EXT4_SB(sb);
89
90	if (!ext4_has_metadata_csum(sb))
91		return;
92
93	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
94	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
95	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
96		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
97}
98