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author | Sage Weil <sage@newdream.net> | 2009-11-07 06:55:25 +0100 |
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committer | Sage Weil <sage@newdream.net> | 2009-11-07 06:55:25 +0100 |
commit | 1654dd0cf5ee1827322aca156af7d96d757201c7 (patch) | |
tree | ba71b1a1e214b929937f02a1794b3d32b8ff1342 /fs/ceph/ceph_fs.c | |
parent | ceph: use strong hash function for mapping objects to pgs (diff) | |
download | linux-1654dd0cf5ee1827322aca156af7d96d757201c7.tar.xz linux-1654dd0cf5ee1827322aca156af7d96d757201c7.zip |
ceph: make object hash a pg_pool property
The object will be hashed to a placement seed (ps) based on the pg_pool's
hash function. This allows new hashes to be introduced into an existing
object store, or selection of a hash appropriate to the objects that
will be stored in a particular pool.
Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph/ceph_fs.c')
-rw-r--r-- | fs/ceph/ceph_fs.c | 77 |
1 files changed, 0 insertions, 77 deletions
diff --git a/fs/ceph/ceph_fs.c b/fs/ceph/ceph_fs.c index b3ecf1b07521..79d76bc4303f 100644 --- a/fs/ceph/ceph_fs.c +++ b/fs/ceph/ceph_fs.c @@ -72,80 +72,3 @@ int ceph_caps_for_mode(int mode) } return 0; } - -/* - * Robert Jenkin's hash function. - * http://burtleburtle.net/bob/hash/evahash.html - * This is in the public domain. - */ -#define mix(a, b, c) \ - do { \ - a = a - b; a = a - c; a = a ^ (c >> 13); \ - b = b - c; b = b - a; b = b ^ (a << 8); \ - c = c - a; c = c - b; c = c ^ (b >> 13); \ - a = a - b; a = a - c; a = a ^ (c >> 12); \ - b = b - c; b = b - a; b = b ^ (a << 16); \ - c = c - a; c = c - b; c = c ^ (b >> 5); \ - a = a - b; a = a - c; a = a ^ (c >> 3); \ - b = b - c; b = b - a; b = b ^ (a << 10); \ - c = c - a; c = c - b; c = c ^ (b >> 15); \ - } while (0) - -unsigned int ceph_full_name_hash(const char *str, unsigned int length) -{ - const unsigned char *k = (const unsigned char *)str; - __u32 a, b, c; /* the internal state */ - __u32 len; /* how many key bytes still need mixing */ - - /* Set up the internal state */ - len = length; - a = 0x9e3779b9; /* the golden ratio; an arbitrary value */ - b = a; - c = 0; /* variable initialization of internal state */ - - /* handle most of the key */ - while (len >= 12) { - a = a + (k[0] + ((__u32)k[1] << 8) + ((__u32)k[2] << 16) + - ((__u32)k[3] << 24)); - b = b + (k[4] + ((__u32)k[5] << 8) + ((__u32)k[6] << 16) + - ((__u32)k[7] << 24)); - c = c + (k[8] + ((__u32)k[9] << 8) + ((__u32)k[10] << 16) + - ((__u32)k[11] << 24)); - mix(a, b, c); - k = k + 12; - len = len - 12; - } - - /* handle the last 11 bytes */ - c = c + length; - switch (len) { /* all the case statements fall through */ - case 11: - c = c + ((__u32)k[10] << 24); - case 10: - c = c + ((__u32)k[9] << 16); - case 9: - c = c + ((__u32)k[8] << 8); - /* the first byte of c is reserved for the length */ - case 8: - b = b + ((__u32)k[7] << 24); - case 7: - b = b + ((__u32)k[6] << 16); - case 6: - b = b + ((__u32)k[5] << 8); - case 5: - b = b + k[4]; - case 4: - a = a + ((__u32)k[3] << 24); - case 3: - a = a + ((__u32)k[2] << 16); - case 2: - a = a + ((__u32)k[1] << 8); - case 1: - a = a + k[0]; - /* case 0: nothing left to add */ - } - mix(a, b, c); - - return c; -} - |