android_kernel_oneplus_msm8998/fs/f2fs/hash.c
Jaegeuk Kim 13f002354d f2fs: catch up to v4.14-rc1
This is cherry-picked from upstrea-f2fs-stable-linux-4.4.y.

Changes include:

commit c7fd9e2b4a ("f2fs: hurry up to issue discard after io interruption")
commit 603dde3965 ("f2fs: fix to show correct discard_granularity in sysfs")
...
commit 565f0225f9 ("f2fs: factor out discard command info into discard_cmd_control")
commit c4cc29d19e ("f2fs: remove batched discard in f2fs_trim_fs")

Change-Id: Icd8a85ac0c19a8aa25cd2591a12b4e9b85bdf1c5
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
2017-10-03 17:19:14 -07:00

108 lines
2.2 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,
struct fscrypt_name *fname)
{
__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;
/* encrypted bigname case */
if (fname && !fname->disk_name.name)
return cpu_to_le32(fname->hash);
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;
}