Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / f2fs / hash.c

diff --git a/kernel/fs/f2fs/hash.c b/kernel/fs/f2fs/hash.c
new file mode 100644 (file)
index 0000000..a844fcf
--- /dev/null
+++ b/kernel/fs/f2fs/hash.c
@@ -0,0 +1,104 @@
+/*
+ * 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 ((len <= 2) && (name[0] == '.') &&
+               (name[1] == '.' || name[1] == '\0'))
+               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;
+}