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/*
  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
 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_RO_COMPAT_FEATURE(sb,
 28					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 29		return 1;
 30
 31	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
 32	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
 33	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
 34		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
 35		provided |= (hi << 16);
 36	} else
 37		calculated &= 0xFFFF;
 38
 39	return provided == calculated;
 40}
 41
 42void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 43				struct ext4_group_desc *gdp,
 44				struct buffer_head *bh, int sz)
 45{
 46	__u32 csum;
 47	struct ext4_sb_info *sbi = EXT4_SB(sb);
 48
 49	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 50					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 51		return;
 52
 53	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
 54	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
 55	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
 56		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
 57}
 58
 59int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
 60				  struct ext4_group_desc *gdp,
 61				  struct buffer_head *bh)
 62{
 63	__u32 hi;
 64	__u32 provided, calculated;
 65	struct ext4_sb_info *sbi = EXT4_SB(sb);
 66	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
 67
 68	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 69					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 70		return 1;
 71
 72	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
 73	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
 74	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
 75		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
 76		provided |= (hi << 16);
 77	} else
 78		calculated &= 0xFFFF;
 79
 80	if (provided == calculated)
 81		return 1;
 82
 83	return 0;
 
 
 84}
 85
 86void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 87				struct ext4_group_desc *gdp,
 88				struct buffer_head *bh)
 89{
 90	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
 91	__u32 csum;
 92	struct ext4_sb_info *sbi = EXT4_SB(sb);
 93
 94	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
 95			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
 96		return;
 97
 98	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
 99	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
100	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
101		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
102}