/* * 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; }