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gerrit-public.fairphone.software / kernel / msm-4.9 / fa77dcfafeaa6bc73293c646bfc3d5192dcf0be2 / . / fs / ext4 / bitmap.c
blob: b319721da26ae32010adcd46db7e2d98ec50887a [file] [log] [blame]
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]1/*
Mingming Cao617ba132006-10-11 01:20:53 -0700[diff] [blame]2 * linux/fs/ext4/bitmap.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]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>
Mingming Caodab291a2006-10-11 01:21:01 -0700[diff] [blame]11#include <linux/jbd2.h>
Christoph Hellwig3dcf5452008-04-29 18:13:32 -0400[diff] [blame]12#include "ext4.h"
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]13
Mingming Cao617ba132006-10-11 01:20:53 -0700[diff] [blame]14#ifdef EXT4FS_DEBUG
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]15
Philippe De Muyterfebfcf92007-10-16 23:26:15 -0700[diff] [blame]16static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]17
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500[diff] [blame]18unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]19{
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500[diff] [blame]20 unsigned int i, sum = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]21
22 if (!map)
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400[diff] [blame]23 return 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]24 for (i = 0; i < numchars; i++)
25 sum += nibblemap[map->b_data[i] & 0xf] +
26 nibblemap[(map->b_data[i] >> 4) & 0xf];
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400[diff] [blame]27 return sum;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]28}
29
Mingming Cao617ba132006-10-11 01:20:53 -0700[diff] [blame]30#endif /* EXT4FS_DEBUG */
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700[diff] [blame]31
Darrick J. Wong41a246d2012-04-29 18:33:10 -0400[diff] [blame]32int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
33 struct ext4_group_desc *gdp,
34 struct buffer_head *bh, int sz)
35{
36 __u32 hi;
37 __u32 provided, calculated;
38 struct ext4_sb_info *sbi = EXT4_SB(sb);
39
40 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
41 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
42 return 1;
43
44 provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
45 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
46 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
47 hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
48 provided |= (hi << 16);
49 } else
50 calculated &= 0xFFFF;
51
52 return provided == calculated;
53}
54
55void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
56 struct ext4_group_desc *gdp,
57 struct buffer_head *bh, int sz)
58{
59 __u32 csum;
60 struct ext4_sb_info *sbi = EXT4_SB(sb);
61
62 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
63 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
64 return;
65
66 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
67 gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
68 if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
69 gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
70}
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400[diff] [blame^]71
72int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
73 struct ext4_group_desc *gdp,
74 struct buffer_head *bh, int sz)
75{
76 __u32 hi;
77 __u32 provided, calculated;
78 struct ext4_sb_info *sbi = EXT4_SB(sb);
79
80 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
81 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
82 return 1;
83
84 provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
85 calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
86 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
87 hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
88 provided |= (hi << 16);
89 } else
90 calculated &= 0xFFFF;
91
92 if (provided == calculated)
93 return 1;
94
95 ext4_error(sb, "Bad block bitmap checksum: block_group = %u", group);
96 return 0;
97}
98
99void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
100 struct ext4_group_desc *gdp,
101 struct buffer_head *bh, int sz)
102{
103 __u32 csum;
104 struct ext4_sb_info *sbi = EXT4_SB(sb);
105
106 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
107 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
108 return;
109
110 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
111 gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
112 if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
113 gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
114}