[mirror_ubuntu-focal-kernel.git] / fs / ext4 / bitmap.c

/*
 *  linux/fs/ext4/bitmap.c
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card (card@masi.ibp.fr)
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 */

#include <linux/buffer_head.h>
#include <linux/jbd2.h>
#include "ext4.h"

static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};

unsigned int ext4_count_free(char *bitmap, unsigned int numchars)
{
	unsigned int i, sum = 0;

	for (i = 0; i < numchars; i++)
		sum += nibblemap[bitmap[i] & 0xf] +
			nibblemap[(bitmap[i] >> 4) & 0xf];
	return sum;
}

int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
				  struct ext4_group_desc *gdp,
				  struct buffer_head *bh, int sz)
{
	__u32 hi;
	__u32 provided, calculated;
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
		return 1;

	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) {
		hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi);
		provided |= (hi << 16);
	} else
		calculated &= 0xFFFF;

	return provided == calculated;
}

void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
				struct ext4_group_desc *gdp,
				struct buffer_head *bh, int sz)
{
	__u32 csum;
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
		return;

	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
	gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
	if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END)
		gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16);
}

int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
				  struct ext4_group_desc *gdp,
				  struct buffer_head *bh, int sz)
{
	__u32 hi;
	__u32 provided, calculated;
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
		return 1;

	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
	calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END) {
		hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi);
		provided |= (hi << 16);
	} else
		calculated &= 0xFFFF;

	if (provided == calculated)
		return 1;

	ext4_error(sb, "Bad block bitmap checksum: block_group = %u", group);
	return 0;
}

void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
				struct ext4_group_desc *gdp,
				struct buffer_head *bh, int sz)
{
	__u32 csum;
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
		return;

	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
	gdp->bg_block_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF);
	if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_END)
		gdp->bg_block_bitmap_csum_hi = cpu_to_le16(csum >> 16);
}
Commit	Line	Data
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] +
f6fb99ca TT	22	nibblemap[(bitmap[i] >> 4) & 0xf];
af5bc92d	23	return sum;
ac27a0ec DK	24	}
ac27a0ec DK	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	}