104 lines
2.0 KiB
C
104 lines
2.0 KiB
C
/*
|
|
* fs/f2fs/hash.c
|
|
*
|
|
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
|
|
* http://www.samsung.com/
|
|
*
|
|
* Portions of this code from linux/fs/ext3/hash.c
|
|
*
|
|
* Copyright (C) 2002 by Theodore Ts'o
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/types.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/f2fs_fs.h>
|
|
#include <linux/cryptohash.h>
|
|
#include <linux/pagemap.h>
|
|
|
|
#include "f2fs.h"
|
|
|
|
/*
|
|
* Hashing code copied from ext3
|
|
*/
|
|
#define DELTA 0x9E3779B9
|
|
|
|
static void TEA_transform(unsigned int buf[4], unsigned int const in[])
|
|
{
|
|
__u32 sum = 0;
|
|
__u32 b0 = buf[0], b1 = buf[1];
|
|
__u32 a = in[0], b = in[1], c = in[2], d = in[3];
|
|
int n = 16;
|
|
|
|
do {
|
|
sum += DELTA;
|
|
b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
|
|
b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
|
|
} while (--n);
|
|
|
|
buf[0] += b0;
|
|
buf[1] += b1;
|
|
}
|
|
|
|
static void str2hashbuf(const unsigned char *msg, size_t len,
|
|
unsigned int *buf, int num)
|
|
{
|
|
unsigned pad, val;
|
|
int i;
|
|
|
|
pad = (__u32)len | ((__u32)len << 8);
|
|
pad |= pad << 16;
|
|
|
|
val = pad;
|
|
if (len > num * 4)
|
|
len = num * 4;
|
|
for (i = 0; i < len; i++) {
|
|
if ((i % 4) == 0)
|
|
val = pad;
|
|
val = msg[i] + (val << 8);
|
|
if ((i % 4) == 3) {
|
|
*buf++ = val;
|
|
val = pad;
|
|
num--;
|
|
}
|
|
}
|
|
if (--num >= 0)
|
|
*buf++ = val;
|
|
while (--num >= 0)
|
|
*buf++ = pad;
|
|
}
|
|
|
|
f2fs_hash_t f2fs_dentry_hash(const struct qstr *name_info)
|
|
{
|
|
__u32 hash;
|
|
f2fs_hash_t f2fs_hash;
|
|
const unsigned char *p;
|
|
__u32 in[8], buf[4];
|
|
const unsigned char *name = name_info->name;
|
|
size_t len = name_info->len;
|
|
|
|
if (is_dot_dotdot(name_info))
|
|
return 0;
|
|
|
|
/* Initialize the default seed for the hash checksum functions */
|
|
buf[0] = 0x67452301;
|
|
buf[1] = 0xefcdab89;
|
|
buf[2] = 0x98badcfe;
|
|
buf[3] = 0x10325476;
|
|
|
|
p = name;
|
|
while (1) {
|
|
str2hashbuf(p, len, in, 4);
|
|
TEA_transform(buf, in);
|
|
p += 16;
|
|
if (len <= 16)
|
|
break;
|
|
len -= 16;
|
|
}
|
|
hash = buf[0];
|
|
f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
|
|
return f2fs_hash;
|
|
}
|