Btrfs: Use a chunk of the key flags to record the item type.

Add (untested and simple) directory item code
Fix comp_keys to use the new key ordering
Add btrfs_insert_empty_item

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 86 insertions, 0 deletions

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
new file mode 100644
index 000000000000..92c37eece1f2
--- /dev/null
+++ b/fs/btrfs/hash.c
@@ -0,0 +1,86 @@
+/*
+ *  Original copy from:
+ *  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 "kerncompat.h"
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(__u32 buf[2], __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;
+}
+
+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;
+}
+
+int btrfs_name_hash(const char *name, int len, u64 *hash_result)
+{
+        __u32   hash;
+        __u32   minor_hash = 0;
+        const char      *p;
+        __u32           in[8], buf[2];
+
+        /* Initialize the default seed for the hash checksum functions */
+        buf[0] = 0x67452301;
+        buf[1] = 0xefcdab89;
+        buf[2] = 0x98badcfe;
+        buf[3] = 0x10325476;
+
+        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];
+        *hash_result = buf[0];
+        *hash_result <<= 32;
+        *hash_result |= buf[1];
+        return 0;
+}