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 <linux/jbd2.h>
12#include "ext4.h"
13
14#ifdef EXT4FS_DEBUG
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
15
16static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
 
17
18unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars)
 
 
19{
20	unsigned int i, sum = 0;
 
 
 
 
21
22	if (!map)
23		return 0;
24	for (i = 0; i < numchars; i++)
25		sum += nibblemap[map->b_data[i] & 0xf] +
26			nibblemap[(map->b_data[i] >> 4) & 0xf];
27	return sum;
28}
29
30#endif  /*  EXT4FS_DEBUG  */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
31

 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
14unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
15{
16	return numchars * BITS_PER_BYTE - memweight(bitmap, numchars);
17}
18
19int 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
41void 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
57int 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
83void 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}