Commit | Line | Data |
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ac27a0ec | 1 | /* |
617ba13b | 2 | * linux/fs/ext4/bitmap.c |
ac27a0ec DK |
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> | |
dab291af | 11 | #include <linux/jbd2.h> |
3dcf5451 | 12 | #include "ext4.h" |
ac27a0ec | 13 | |
febfcf91 | 14 | static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; |
ac27a0ec | 15 | |
f6fb99ca | 16 | unsigned int ext4_count_free(char *bitmap, unsigned int numchars) |
ac27a0ec | 17 | { |
498e5f24 | 18 | unsigned int i, sum = 0; |
ac27a0ec | 19 | |
ac27a0ec | 20 | for (i = 0; i < numchars; i++) |
f6fb99ca TT |
21 | sum += nibblemap[bitmap[i] & 0xf] + |
22 | nibblemap[(bitmap[i] >> 4) & 0xf]; | |
af5bc92d | 23 | return sum; |
ac27a0ec DK |
24 | } |
25 | ||
41a246d1 DW |
26 | int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, |
27 | struct ext4_group_desc *gdp, | |
28 | struct buffer_head *bh, int sz) | |
29 | { | |
30 | __u32 hi; | |
31 | __u32 provided, calculated; | |
32 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
33 | ||
34 | if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, | |
35 | EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) | |
36 | return 1; | |
37 | ||
38 | provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo); | |
39 | calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); | |
40 | if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) { | |
41 | hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi); | |
42 | provided |= (hi << 16); | |
43 | } else | |
44 | calculated &= 0xFFFF; | |
45 | ||
46 | return provided == calculated; | |
47 | } | |
48 | ||
49 | void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, | |
50 | struct ext4_group_desc *gdp, | |
51 | struct buffer_head *bh, int sz) | |
52 | { | |
53 | __u32 csum; | |
54 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
55 | ||
56 | if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, | |
57 | EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) | |
58 | return; | |
59 | ||
60 | csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); | |
61 | gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); | |
62 | if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) | |
63 | gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16); | |
64 | } | |
fa77dcfa DW |
65 | |
66 | int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, | |
67 | struct ext4_group_desc *gdp, | |
68 | struct buffer_head *bh, int sz) | |
69 | { | |
70 | __u32 hi; | |
71 | __u32 provided, calculated; | |
72 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
73 | ||
74 | if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, | |
75 | EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) | |
76 | return 1; | |
77 | ||
78 | provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo); | |
79 | calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); | |
80 | if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) { | |
81 | hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi); | |
82 | provided |= (hi << 16); | |
83 | } else | |
84 | calculated &= 0xFFFF; | |
85 | ||
86 | if (provided == calculated) | |
87 | return 1; | |
88 | ||
89 | ext4_error(sb, "Bad block bitmap checksum: block_group = %u", group); | |
90 | return 0; | |
91 | } | |
92 | ||
93 | void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group, | |
94 | struct ext4_group_desc *gdp, | |
95 | struct buffer_head *bh, int sz) | |
96 | { | |
97 | __u32 csum; | |
98 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
99 | ||
100 | if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, | |
101 | EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) | |
102 | return; | |
103 | ||
104 | csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); | |
105 | gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); | |
106 | if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) | |
107 | gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16); | |
108 | } |