2 * Copyright (C) 2002 by Theodore Ts'o
4 * This file is released under the GPL v2.
6 * This file may be redistributed under the terms of the GNU Public
11 * obdclass/hash.c is copied from ldiskfs/hash.c.
12 * ldiskfs is used by server only.
13 * obdclass is shared by both client and server, it should not depend on ldiskfs.
17 #include <linux/sched.h>
18 #ifdef HAVE_SERVER_SUPPORT
20 #ifdef HAVE_EXT4_LDISKFS
21 #include <ldiskfs/ldiskfs_jbd2.h>
22 #include <ldiskfs/ldiskfs.h>
24 #include <linux/jbd.h>
25 #include <linux/ldiskfs_fs.h>
29 # include <obd_class.h>
32 #define DELTA 0x9E3779B9
35 static void TEA_transform(__u32 buf[4], __u32 const in[])
38 __u32 b0 = buf[0], b1 = buf[1];
39 __u32 a = in[0], b = in[1], c = in[2], d = in[3];
44 b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
45 b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
52 /* F, G and H are basic MD4 functions: selection, majority, parity */
53 #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
54 #define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
55 #define H(x, y, z) ((x) ^ (y) ^ (z))
58 * The generic round function. The application is so specific that
59 * we don't bother protecting all the arguments with parens, as is generally
60 * good macro practice, in favor of extra legibility.
61 * Rotation is separate from addition to prevent recomputation
63 #define ROUND(f, a, b, c, d, x, s) \
64 (a += f(b, c, d) + x, a = (a << s) | (a >> (32-s)))
66 #define K2 013240474631UL
67 #define K3 015666365641UL
70 * Basic cut-down MD4 transform. Returns only 32 bits of result.
72 static void halfMD4Transform (__u32 buf[4], __u32 const in[])
74 __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
77 ROUND(F, a, b, c, d, in[0] + K1, 3);
78 ROUND(F, d, a, b, c, in[1] + K1, 7);
79 ROUND(F, c, d, a, b, in[2] + K1, 11);
80 ROUND(F, b, c, d, a, in[3] + K1, 19);
81 ROUND(F, a, b, c, d, in[4] + K1, 3);
82 ROUND(F, d, a, b, c, in[5] + K1, 7);
83 ROUND(F, c, d, a, b, in[6] + K1, 11);
84 ROUND(F, b, c, d, a, in[7] + K1, 19);
87 ROUND(G, a, b, c, d, in[1] + K2, 3);
88 ROUND(G, d, a, b, c, in[3] + K2, 5);
89 ROUND(G, c, d, a, b, in[5] + K2, 9);
90 ROUND(G, b, c, d, a, in[7] + K2, 13);
91 ROUND(G, a, b, c, d, in[0] + K2, 3);
92 ROUND(G, d, a, b, c, in[2] + K2, 5);
93 ROUND(G, c, d, a, b, in[4] + K2, 9);
94 ROUND(G, b, c, d, a, in[6] + K2, 13);
97 ROUND(H, a, b, c, d, in[3] + K3, 3);
98 ROUND(H, d, a, b, c, in[7] + K3, 9);
99 ROUND(H, c, d, a, b, in[2] + K3, 11);
100 ROUND(H, b, c, d, a, in[6] + K3, 15);
101 ROUND(H, a, b, c, d, in[1] + K3, 3);
102 ROUND(H, d, a, b, c, in[5] + K3, 9);
103 ROUND(H, c, d, a, b, in[0] + K3, 11);
104 ROUND(H, b, c, d, a, in[4] + K3, 15);
120 /* The old legacy hash */
121 static __u32 dx_hack_hash (const char *name, int len)
123 __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
125 __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
127 if (hash & 0x80000000) hash -= 0x7fffffff;
134 static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
139 pad = (__u32)len | ((__u32)len << 8);
145 for (i=0; i < len; i++) {
148 val = msg[i] + (val << 8);
162 * Returns the hash of a filename. If len is 0 and name is NULL, then
163 * this function can be used to test whether or not a hash version is
166 * The seed is an 4 longword (32 bits) "secret" which can be used to
167 * uniquify a hash. If the seed is all zero's, then some default seed
170 * A particular hash version specifies whether or not the seed is
171 * represented, and whether or not the returned hash is 32 bits or 64
172 * bits. 32 bit hashes will return 0 for the minor hash.
174 int ldiskfsfs_dirhash(const char *name, int len, struct ldiskfs_dx_hash_info *hinfo)
177 __u32 minor_hash = 0;
182 /* Initialize the default seed for the hash checksum functions */
188 /* Check to see if the seed is all zero's */
190 for (i=0; i < 4; i++) {
195 memcpy(buf, hinfo->seed, sizeof(buf));
198 switch (hinfo->hash_version) {
199 case LDISKFS_DX_HASH_LEGACY:
200 hash = dx_hack_hash(name, len);
202 case LDISKFS_DX_HASH_HALF_MD4:
205 str2hashbuf(p, len, in, 8);
206 halfMD4Transform(buf, in);
213 case LDISKFS_DX_HASH_TEA:
216 str2hashbuf(p, len, in, 4);
217 TEA_transform(buf, in);
229 if (hash == (LDISKFS_HTREE_EOF << 1))
230 hash = (LDISKFS_HTREE_EOF-1) << 1;
232 hinfo->minor_hash = minor_hash;