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
 
 
 14static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
 15
 16unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
 17{
 18	unsigned int i, sum = 0;
 19
 
 
 20	for (i = 0; i < numchars; i++)
 21		sum += nibblemap[bitmap[i] & 0xf] +
 22			nibblemap[(bitmap[i] >> 4) & 0xf];
 23	return sum;
 24}
 25
 26int 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
 49void 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}
 65
 66int 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	return 0;
 90}
 91
 92void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 93				struct ext4_group_desc *gdp,
 94				struct buffer_head *bh, int sz)
 95{
 96	__u32 csum;
 97	struct ext4_sb_info *sbi = EXT4_SB(sb);
 98
 99	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
100			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
101		return;
102
103	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
104	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
105	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
106		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
107}

 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