1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext4/bitmap.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 */
10
11 #include <linux/buffer_head.h>
12 #include "ext4.h"
13
ext4_count_free(char * bitmap,unsigned int numchars)14 unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
15 {
16 return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
17 }
18
ext4_inode_bitmap_csum_verify(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh,int sz)19 int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
20 struct ext4_group_desc *gdp,
21 struct buffer_head *bh, int sz)
22 {
23 __u32 hi;
24 __u32 provided, calculated;
25 struct ext4_sb_info *sbi = EXT4_SB(sb);
26
27 if (!ext4_has_metadata_csum(sb))
28 return 1;
29
30 provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
31 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
32 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
33 hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
34 provided |= (hi << 16);
35 } else
36 calculated &= 0xFFFF;
37
38 return provided == calculated;
39 }
40
ext4_inode_bitmap_csum_set(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh,int sz)41 void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
42 struct ext4_group_desc *gdp,
43 struct buffer_head *bh, int sz)
44 {
45 __u32 csum;
46 struct ext4_sb_info *sbi = EXT4_SB(sb);
47
48 if (!ext4_has_metadata_csum(sb))
49 return;
50
51 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
52 gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
53 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
54 gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
55 }
56
ext4_block_bitmap_csum_verify(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh)57 int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
58 struct ext4_group_desc *gdp,
59 struct buffer_head *bh)
60 {
61 __u32 hi;
62 __u32 provided, calculated;
63 struct ext4_sb_info *sbi = EXT4_SB(sb);
64 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
65
66 if (!ext4_has_metadata_csum(sb))
67 return 1;
68
69 provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
70 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
71 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
72 hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
73 provided |= (hi << 16);
74 } else
75 calculated &= 0xFFFF;
76
77 if (provided == calculated)
78 return 1;
79
80 return 0;
81 }
82
ext4_block_bitmap_csum_set(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh)83 void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
84 struct ext4_group_desc *gdp,
85 struct buffer_head *bh)
86 {
87 int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
88 __u32 csum;
89 struct ext4_sb_info *sbi = EXT4_SB(sb);
90
91 if (!ext4_has_metadata_csum(sb))
92 return;
93
94 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
95 gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
96 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
97 gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
98 }
99