diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/ext3/hash.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/ext3/hash.c')
-rw-r--r-- | fs/ext3/hash.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c new file mode 100644 index 000000000000..5a2d1235ead0 --- /dev/null +++ b/fs/ext3/hash.c | |||
@@ -0,0 +1,152 @@ | |||
1 | /* | ||
2 | * linux/fs/ext3/hash.c | ||
3 | * | ||
4 | * Copyright (C) 2002 by Theodore Ts'o | ||
5 | * | ||
6 | * This file is released under the GPL v2. | ||
7 | * | ||
8 | * This file may be redistributed under the terms of the GNU Public | ||
9 | * License. | ||
10 | */ | ||
11 | |||
12 | #include <linux/fs.h> | ||
13 | #include <linux/jbd.h> | ||
14 | #include <linux/sched.h> | ||
15 | #include <linux/ext3_fs.h> | ||
16 | #include <linux/cryptohash.h> | ||
17 | |||
18 | #define DELTA 0x9E3779B9 | ||
19 | |||
20 | static void TEA_transform(__u32 buf[4], __u32 const in[]) | ||
21 | { | ||
22 | __u32 sum = 0; | ||
23 | __u32 b0 = buf[0], b1 = buf[1]; | ||
24 | __u32 a = in[0], b = in[1], c = in[2], d = in[3]; | ||
25 | int n = 16; | ||
26 | |||
27 | do { | ||
28 | sum += DELTA; | ||
29 | b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); | ||
30 | b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); | ||
31 | } while(--n); | ||
32 | |||
33 | buf[0] += b0; | ||
34 | buf[1] += b1; | ||
35 | } | ||
36 | |||
37 | |||
38 | /* The old legacy hash */ | ||
39 | static __u32 dx_hack_hash (const char *name, int len) | ||
40 | { | ||
41 | __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9; | ||
42 | while (len--) { | ||
43 | __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373)); | ||
44 | |||
45 | if (hash & 0x80000000) hash -= 0x7fffffff; | ||
46 | hash1 = hash0; | ||
47 | hash0 = hash; | ||
48 | } | ||
49 | return (hash0 << 1); | ||
50 | } | ||
51 | |||
52 | static void str2hashbuf(const char *msg, int len, __u32 *buf, int num) | ||
53 | { | ||
54 | __u32 pad, val; | ||
55 | int i; | ||
56 | |||
57 | pad = (__u32)len | ((__u32)len << 8); | ||
58 | pad |= pad << 16; | ||
59 | |||
60 | val = pad; | ||
61 | if (len > num*4) | ||
62 | len = num * 4; | ||
63 | for (i=0; i < len; i++) { | ||
64 | if ((i % 4) == 0) | ||
65 | val = pad; | ||
66 | val = msg[i] + (val << 8); | ||
67 | if ((i % 4) == 3) { | ||
68 | *buf++ = val; | ||
69 | val = pad; | ||
70 | num--; | ||
71 | } | ||
72 | } | ||
73 | if (--num >= 0) | ||
74 | *buf++ = val; | ||
75 | while (--num >= 0) | ||
76 | *buf++ = pad; | ||
77 | } | ||
78 | |||
79 | /* | ||
80 | * Returns the hash of a filename. If len is 0 and name is NULL, then | ||
81 | * this function can be used to test whether or not a hash version is | ||
82 | * supported. | ||
83 | * | ||
84 | * The seed is an 4 longword (32 bits) "secret" which can be used to | ||
85 | * uniquify a hash. If the seed is all zero's, then some default seed | ||
86 | * may be used. | ||
87 | * | ||
88 | * A particular hash version specifies whether or not the seed is | ||
89 | * represented, and whether or not the returned hash is 32 bits or 64 | ||
90 | * bits. 32 bit hashes will return 0 for the minor hash. | ||
91 | */ | ||
92 | int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo) | ||
93 | { | ||
94 | __u32 hash; | ||
95 | __u32 minor_hash = 0; | ||
96 | const char *p; | ||
97 | int i; | ||
98 | __u32 in[8], buf[4]; | ||
99 | |||
100 | /* Initialize the default seed for the hash checksum functions */ | ||
101 | buf[0] = 0x67452301; | ||
102 | buf[1] = 0xefcdab89; | ||
103 | buf[2] = 0x98badcfe; | ||
104 | buf[3] = 0x10325476; | ||
105 | |||
106 | /* Check to see if the seed is all zero's */ | ||
107 | if (hinfo->seed) { | ||
108 | for (i=0; i < 4; i++) { | ||
109 | if (hinfo->seed[i]) | ||
110 | break; | ||
111 | } | ||
112 | if (i < 4) | ||
113 | memcpy(buf, hinfo->seed, sizeof(buf)); | ||
114 | } | ||
115 | |||
116 | switch (hinfo->hash_version) { | ||
117 | case DX_HASH_LEGACY: | ||
118 | hash = dx_hack_hash(name, len); | ||
119 | break; | ||
120 | case DX_HASH_HALF_MD4: | ||
121 | p = name; | ||
122 | while (len > 0) { | ||
123 | str2hashbuf(p, len, in, 8); | ||
124 | half_md4_transform(buf, in); | ||
125 | len -= 32; | ||
126 | p += 32; | ||
127 | } | ||
128 | minor_hash = buf[2]; | ||
129 | hash = buf[1]; | ||
130 | break; | ||
131 | case DX_HASH_TEA: | ||
132 | p = name; | ||
133 | while (len > 0) { | ||
134 | str2hashbuf(p, len, in, 4); | ||
135 | TEA_transform(buf, in); | ||
136 | len -= 16; | ||
137 | p += 16; | ||
138 | } | ||
139 | hash = buf[0]; | ||
140 | minor_hash = buf[1]; | ||
141 | break; | ||
142 | default: | ||
143 | hinfo->hash = 0; | ||
144 | return -1; | ||
145 | } | ||
146 | hash = hash & ~1; | ||
147 | if (hash == (EXT3_HTREE_EOF << 1)) | ||
148 | hash = (EXT3_HTREE_EOF-1) << 1; | ||
149 | hinfo->hash = hash; | ||
150 | hinfo->minor_hash = minor_hash; | ||
151 | return 0; | ||
152 | } | ||