[PATCH] ext4: initial copy of files from ext3
Start of the ext4 patch series. See Documentation/filesystems/ext4.txt for
details.
This is a simple copy of the files in fs/ext3 to fs/ext4 and
/usr/incude/linux/ext3* to /usr/include/ex4*
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ext4/hash.c b/fs/ext4/hash.c
new file mode 100644
index 0000000..deeb27b
--- /dev/null
+++ b/fs/ext4/hash.c
@@ -0,0 +1,152 @@
+/*
+ * linux/fs/ext3/hash.c
+ *
+ * Copyright (C) 2002 by Theodore Ts'o
+ *
+ * This file is released under the GPL v2.
+ *
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/sched.h>
+#include <linux/ext3_fs.h>
+#include <linux/cryptohash.h>
+
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(__u32 buf[4], __u32 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;
+}
+
+
+/* The old legacy hash */
+static __u32 dx_hack_hash (const char *name, int len)
+{
+ __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+ while (len--) {
+ __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
+
+ if (hash & 0x80000000) hash -= 0x7fffffff;
+ hash1 = hash0;
+ hash0 = hash;
+ }
+ return (hash0 << 1);
+}
+
+static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
+{
+ __u32 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;
+}
+
+/*
+ * Returns the hash of a filename. If len is 0 and name is NULL, then
+ * this function can be used to test whether or not a hash version is
+ * supported.
+ *
+ * The seed is an 4 longword (32 bits) "secret" which can be used to
+ * uniquify a hash. If the seed is all zero's, then some default seed
+ * may be used.
+ *
+ * A particular hash version specifies whether or not the seed is
+ * represented, and whether or not the returned hash is 32 bits or 64
+ * bits. 32 bit hashes will return 0 for the minor hash.
+ */
+int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
+{
+ __u32 hash;
+ __u32 minor_hash = 0;
+ const char *p;
+ int i;
+ __u32 in[8], buf[4];
+
+ /* Initialize the default seed for the hash checksum functions */
+ buf[0] = 0x67452301;
+ buf[1] = 0xefcdab89;
+ buf[2] = 0x98badcfe;
+ buf[3] = 0x10325476;
+
+ /* Check to see if the seed is all zero's */
+ if (hinfo->seed) {
+ for (i=0; i < 4; i++) {
+ if (hinfo->seed[i])
+ break;
+ }
+ if (i < 4)
+ memcpy(buf, hinfo->seed, sizeof(buf));
+ }
+
+ switch (hinfo->hash_version) {
+ case DX_HASH_LEGACY:
+ hash = dx_hack_hash(name, len);
+ break;
+ case DX_HASH_HALF_MD4:
+ p = name;
+ while (len > 0) {
+ str2hashbuf(p, len, in, 8);
+ half_md4_transform(buf, in);
+ len -= 32;
+ p += 32;
+ }
+ minor_hash = buf[2];
+ hash = buf[1];
+ break;
+ case DX_HASH_TEA:
+ p = name;
+ while (len > 0) {
+ str2hashbuf(p, len, in, 4);
+ TEA_transform(buf, in);
+ len -= 16;
+ p += 16;
+ }
+ hash = buf[0];
+ minor_hash = buf[1];
+ break;
+ default:
+ hinfo->hash = 0;
+ return -1;
+ }
+ hash = hash & ~1;
+ if (hash == (EXT3_HTREE_EOF << 1))
+ hash = (EXT3_HTREE_EOF-1) << 1;
+ hinfo->hash = hash;
+ hinfo->minor_hash = minor_hash;
+ return 0;
+}