diff options
author | Chris Mason <chris.mason@oracle.com> | 2007-03-15 12:56:47 -0400 |
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committer | David Woodhouse <dwmw2@hera.kernel.org> | 2007-03-15 12:56:47 -0400 |
commit | 62e2749e03a855d98855f9ce032dbe72d5fad148 (patch) | |
tree | ed12521d1bde4ac7eda7f917b57b3cab1e76539d /fs/btrfs/hash.c | |
parent | a1516c8921ce2c148b69493e858d95bc79c92f01 (diff) |
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>
Diffstat (limited to 'fs/btrfs/hash.c')
-rw-r--r-- | fs/btrfs/hash.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c new file mode 100644 index 00000000000..92c37eece1f --- /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; +} |