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
ext4_count_free(char * bitmap,unsigned int numchars)13 unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
14 {
15 return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
16 }
17
ext4_inode_bitmap_csum_verify(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh,int sz)18 int 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
ext4_inode_bitmap_csum_set(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh,int sz)40 void 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
ext4_block_bitmap_csum_verify(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh)56 int 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
ext4_block_bitmap_csum_set(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct buffer_head * bh)82 void 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